Shock wave therapy for rotator cuff disease with or without calcification

Summary of findings for the main comparison. Shock wave therapy versus placebo for rotator cuff disease with or without calcification

Shock wave therapy for rotator cuff disease with or without calcification at 3 months
Patient or population: rotator cuff disease with or without calcification Setting: outpatient clinic Intervention: shock wave therapy Comparison: placebo therapy
Outcomes	*Anticipated absolute effects (95% CI)**		Relative effect (95% CI)	№ of participants (studies)	Certainty of the evidence (GRADE)	Comments
Outcomes	Risk with placebo	Risk with shock wave therapy	Relative effect (95% CI)	№ of participants (studies)	Certainty of the evidence (GRADE)	Comments
Pain relief > 50%^a Follow‐up: 3 months	375 per 1000	413 per 1000 (232 to 728)	RR 1.10 (0.62 to 1.94)	74 (1 study)	⊕⊕⊝⊝ Low^b,c	Shockwave therapy may provide no improvement in the number of participants with a pain reduction of 50% or more. Absolute change 4% more had relief (19% fewer to 26% more); relative change 10% more had relief (38% fewer to 94% more); NNTB: NA^d
Pain Multiple scales^e translated to VAS 0–10 (10 was severe pain)^f Follow‐up: 3 months	Mean pain in the control group was 3.02 points^g	Mean pain in the intervention group was 0.78 points better (0.17 better to 1.4 better)	SMD –0.49 (95% CI –0.88 to –0.11)	608 (9 studies)	⊕⊕⊕⊝ Moderate^h	Shockwave therapy probably results in little or no clinically important improvement in pain. Mean pain did not appear to differ in participants with and without calcification: test for subgroup differences: Chi² = 0.25, df = 1 (P = 0.62), I² = 0% Absolute change 8% better (2% to 14% better); relative change 14% better (3% better to 25% better);ⁱ NNTB: 4 (95% CI 2 to 34)^d
Function Multiple scales^e translated to Constant 0–100 scale (100 was best function)f Follow‐up: 3 months	Mean function in the control group was 66 points^g	Mean function in the intervention group was 7.9 points better (1.6 better to 14 better)	SMD 0.62 (95% CI 0.13 to 1.11)	612 (9 studies)	⊕⊕⊕⊝ Moderate^j	Shockwave therapy probably results in little or no clinically important improvement in function. Mean function did not appear to differ in participants with and without calcification: test for subgroup differences: Chi² = 1.00, df = 1 (P = 0.32), I² = 0.1% Absolute change: 8% better (1.6% to 14% better); relative change 12% better (3% to 22% better);ⁱ NNTB: 3 (95% CI 2 to 18)^d
Participant‐reported success Follow‐up: end of studies	255 per 1000	406 per 1000 (222 to 743)	RR 1.59 (0.87 to 2.91)	287 (6 studies)	⊕⊕⊝⊝ Low^b,c	Shockwave therapy may provide no improvement in the number of participants reporting treatment success. Absolute change 15% more had success (3% fewer to 49% more); relative change 59% more (13% fewer to 191% more); NNTB: NA^d
Quality of life	—	—	—	—	—	Not measured
Number of participant withdrawals due to adverse events or treatment intolerance	103 per 1000	77 per 1000 (44 to 135)	RR 0.75 (0.43 to 1.31)	581 (7 studies)	⊕⊕⊝⊝ Low^b,c	We are uncertain if shockwave therapy increases withdrawal rates. Absolute change 3% less events (6% less to 3% more); relative change 25% less (57% less to 31% more); NNTH: NA^d
Number of participants experiencing any adverse event Follow‐up: 12 months	72 per 1000	260 per 1000 (144 to 469)	RR 3.61 (2.00 to 6.52)	295 (5 studies)	⊕⊕⊝⊝ Low^b,c	We are uncertain if shockwave therapy increases adverse events. Absolute difference: 19% more events (7% more to 40% more); relative change: 261% more (100% more to 552% more); NNTH: NA^d
*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; NA: not applicable; NNTB: number needed to treat for an additional beneficial outcome; RR: risk ratio; SMD: standardised mean difference; VAS: Visual Analogue Scale.
GRADE Working Group grades of evidence High certainty: we are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect. Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect.
^aThe a priori outcome was pain relief 30% or greater, which was not reported in any studies; thus we reported pain relief 50% or greater. ^b Downgraded one level due to study limitations (including risk of selection, detection, attrition, and reporting bias). ^cDowngraded one level for imprecision due to wide confidence intervals, or small number of participants or small number of events. ^dNumber needed to treat for an additional beneficial outcome (NNTB), or an additional harmful outcome (NNTH) not applicable (n/a) when result is not statistically significant. NNTB or NNTH for dichotomous outcomes calculated using Cates NNT calculator (www.nntonline.net/visualrx/). NNTB or NNTH for continuous outcomes calculated using Wells Calculator (CMSG editorial office), with an assumed minimal clinical important difference for pain of 1.5 points on 0 to 10 VAS, and for function of 10 points on 0 to 100 Constant score. ^ePain scores: VAS 0 to 10, VAS 0 to 100, Constant Score 0 to 15 (also called Constant score); function scores: Constant‐Murley 0 to 100, Shoulder Pain And Disability Index 0 to 100. ^fTranslated from SMD and 95% CIs to 0 to 10 VAS for pain and 0 to 100 Constant scale for function by multiplying the SMD by the standard deviation (SD) at baseline in the placebo group from Gerdesmeyer 2003 (values were mean (SD) VAS pain 5.6 (1.6), and mean Constant score (SD) 64.2 (12.8). ^gControl group mean (SD) values at 3 months' follow‐up from Gerdesmeyer 2003: values were 3.8 (2.3) on 0 to 10 VAS pain; 74 (15.5) on 0 to 100 Constant function score. ^h Downgraded one level due to study limitations (including risk of selection, detection, and attrition bias). Although this outcome had a high I² (80%), the outcome was not downgraded for inconsistency. This high I² was due to one outlier,Hsu 2008 and removing this outlier removes the statistical heterogeneity (I² = 0%) and does not change the direction of the effect ⁱRelative changes calculated as absolute change (mean difference) divided by mean at baseline in the control group from Gerdesmeyer 2003 (values were 5.6 on 0 to 10 point VAS pain; 64.2 on 0 to 100 Constant score). ^jDowngraded one level due to study limitations (including risk of selection, detection, and attrition bias), and one level due to inconsistency (I² = 91%). Removing the potential extreme outlier reported in Hsu 2008 still left considerable heterogeneity (I² = 72%), additional removal of another, less extreme outlier (Cosentino 2003) resulted in I² = 38%. As we could explain the heterogeneity, we did not downgrade the certainty further.

Background

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Description of the condition

Shoulder disorders are common, with a reported prevalence ranging from 7% to 26% in adults (Luime 2004). Shoulder problems account for 1.3% of all general practice encounters in Australia (Britt 2016), and up to 14% of all referrals to physiotherapists in the UK (May 2003). Shoulder pain persists or recurs in 40% of people within one year after their first visit to a primary care physician (van der Windt 1996), and has a substantial impact upon quality of life (MacDermid 2004; Taylor 2005).

Rotator cuff disease is the most common cause of shoulder pain seen by physicians (Ostor 2005), and is estimated to occur in up to 50% of people aged 75 years or over (Urwin 1998). The incidence is expected to rise with the ageing of the population (Gomoll 2004). A wide range of pathophysiological conditions are included under the umbrella term of 'rotator cuff disease', including rotator cuff tendonitis or tendinopathy, supraspinatus, infraspinatus or subscapularis tendonitis, subacromial bursitis, and partial and complete rotator cuff tears. There is no uniformity in how these conditions are labelled and defined (Green 1998; Lewis 2009). Among published controlled trials for rotator cuff disease, the definition most commonly used is based on clinical features and includes the presence of positive impingement signs including a painful arc and pain with resisted movements or normal passive range of movement (ROM) (Green 1998).

The pathophysiology of rotator cuff disease has traditionally been viewed as a continuum that ranges from impingement syndrome to partial‐ and full‐thickness rotator cuff tears (Neer 1983). While it is commonly believed that intrinsic degeneration of the rotator cuff tendons together with repetitive microtrauma contribute to its development (Ogata 1990), it is probably multifactorial, and many conflicting theories have been presented (Lewis 2007). Based on magnetic resonance imaging (MRI) scans, asymptomatic partial and full‐thickness rotator cuff tears have been demonstrated in 4% of people aged less than 40 years and in more than 50% of people aged more than 60 years (Sher 1995). It is currently not known how many asymptomatic rotator cuff tears will subsequently become symptomatic. For example, one study of people aged 50 to 80 years who presented with unilateral shoulder pain and had the contralateral shoulder examined by ultrasound suggested that 50% of asymptomatic rotator cuff tears become symptomatic within five years (Yamaguchi 2001). Another study in asymptomatic young elite athletes aged 18 to 38 years participating in sports involving the shoulder, none of the eight athletes with partial or full‐thickness tears found on MRI had developed symptoms five years later (Connor 2003).

The diagnosis of rotator cuff disease in primary care is predominantly made by history and physical examination. People may present with impingement‐type symptoms, pain at night and at rest, and painful movement, with or without features of a torn rotator cuff tendon such as painful weakness and atrophy. The diagnostic utility of various physical examination tests is limited (Hegedus 2008); however, rotator cuff disease is usually distinguishable from adhesive capsulitis by the lack of global restriction of movement. Imaging techniques are also limited in their usefulness for diagnosis. X‐rays may exclude other causes of shoulder pain such as glenohumeral osteoarthritis, calcific tendinitis indicated by the presence of calcific deposits situated just proximal to the rotator cuff insertion in the setting of acute onset of pain, or an acromial spur that might impinge on the rotator cuff. Elevation of the humeral head, together with narrowing of the subacromial space, might indicate the presence of a large rotator cuff tear (Weiner 1970). Imaging modalities such as ultrasound and MRI are able to detect full thickness rotator cuff tears but have less accuracy for detection of partial‐thickness tears (Dinnes 2003; Lewis 2007).

Description of the intervention

The objectives of treatment of symptomatic rotator cuff disease are to relieve pain and restore movement and function of the shoulder. Conservative treatments include corticosteroid injections (Buchbinder 2003), analgesics (Paoloni 2005), non‐steroidal anti‐inflammatories (NSAIDs) (Green 1999), and physical modalities including exercise (Page 2016a; Page 2016b). Topical glyceryl trinitrate has also been proposed as a treatment (Cumpston 2009). These treatments may be used in combination or sequentially. Surgery (decompression with or without rotator cuff repair) is usually reserved for people who do not respond to non‐operative treatment (Karjalainen 2019a; Karjalainen 2019b).

Shock wave therapy can be either extracorporeal or radial. Extracorporeal shock wave therapy (ESWT) is a non‐invasive treatment that involves passing sound waves (or shock waves) through the skin to the affected area, sometimes used with ultrasound‐guided positioning of the device. Shock waves are single pulsed acoustic or sonic waves, which dissipate mechanical energy at the interface of two substances with different acoustic impedance (Loew 1997). They are produced by generators of an electrical energy source and require an electroacoustic conversion mechanism and a focusing device (Ueberle 1997). Three types of systems can be distinguished based upon the sound source: electrohydraulic, electromagnetic and piezoelectric systems. Various doses appear to be used, with no apparent consensus on the minimum therapeutic dose. The definition that will be used throughout this review was defined by Cacchio 2006 as low‐energy shock waves: less than 0.1 mJ/mm² and high‐energy shock waves: 0.2 mJ/mm² to 0.4 mJ/mm²).

Radial shock wave therapy (RSWT) is generated through the acceleration of a projectile inside the handpiece of the treatment device and then transmitted radially from the tip of the applicator to the target zone. Radial shock waves show a lower peak pressure and a considerably longer rise time than extracorporeal shock waves. In RSWT, the focal point is not centred on a target zone, as occurs in ESWT, but on the tip of the applicator (Cacchio 2006).

ESWT has been used since the 1990s to treat various musculoskeletal disorders, but evidence of its efficacy remains equivocal, with trials and reviews reporting conflicting results and there is no known standard dose and treatment protocol. Evidence from one Cochrane systematic review indicated that ESWT did not improve pain and function in lateral elbow pain (Buchbinder 2005; Buchbinder 2006), while another Cochrane Review reported that the evidence for heel pain was equivocal (Crawford 2003). In terms of safety, adverse effects that have been described include local erythema and pain although these are generally minor and short‐lived and no serious adverse effects have been reported.

How the intervention might work

The mechanism of action of ESWT on damaged tendons is not understood. Possible mechanisms have been proposed including overstimulation of pain nerve fibre endings producing an analgesic effect (Melzack 1975; Rompe 1996), or disruption of the tendon tissue by the physical effects of the sound waves (or radial shock wave) resulting in induction of a healing process of the tendon (Loew 1997).

Why it is important to do this review

Despite widespread use of shock wave therapy, evidence of its effectiveness for rotator cuff disease is equivocal. Several systematic reviews have been published (Bannuru 2014; Ioppolo 2013; Vavken 2009; Verstraelen 2014). Three reviews only considered participants with calcific rotator cuff tendinitis (Ioppolo 2013; Vavken 2009; Verstraelen 2014). Vavken 2009 included 14 trials (995 participants) published up to 2008 and concluded that high‐dose ESWT was effective for calcific tendinitis but noted that the conclusions were susceptible to bias. They did not separate placebo from other treatments in their pooled comparative analyses. Ioppolo 2013 included six trials published between 1992 and 2011 and reported that ESWT increased shoulder function, reduced pain and was effective in dissolving calcifications. Verstraelen 2014 included five trials (359 participants) that compared low‐ to high‐energy shock wave therapy for calcific tendinitis and reported that high‐energy shock waves resulted in greater benefits with respect to function and resorption of the calcific deposits at three months compared with low‐energy shock waves. Bannuru 2014 included 28 trials (1745 participants) investigating different energy levels of ESWT for people with both calcific or non‐calcific rotator cuff tendinitis. They were unable to perform any meta‐analyses due to clinical heterogeneity but concluded that high‐energy ESWT was only of benefit for improving pain and function in chronic calcific shoulder tendinitis. An updated high‐quality systematic review is needed to synthesise all the available data up to the present day.

Objectives

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To determine the benefits and harms of shock wave therapy for rotator cuff disease, with or without calcification, and to establish its usefulness in the context of other available treatment options.

Methods

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Criteria for considering studies for this review

Types of studies

Randomised controlled trials (RCTs) and controlled clinical trials (CCTs) that used quasi‐randomised methods to allocate participants, for example by date of birth, hospital record number or alternation. We included trials published in any language.

Types of participants

We included trials with participants described as having rotator cuff disease (rotator cuff tendonitis or tendinopathy, supraspinatus, infraspinatus or subscapularis tendonitis, subacromial bursitis or rotator cuff tears) with or without calcific deposits. We also planned to include studies of multiple soft tissue diseases and pain due to tendonitis in different parts of the body provided that the rotator cuff disease results were presented separately, or greater than 90% of participants in the study had rotator cuff disease, but we did not identify any such studies. We excluded RCTs that included participants with a history of significant injury or systemic inflammatory conditions such as rheumatoid arthritis.

Types of interventions

We included all randomised controlled comparisons of shock wave therapy (ESWT or RSWT) versus placebo, or another treatment, or of varying types and dosages of ESWT. Trials that included co‐interventions were eligible for inclusion provided co‐interventions were given to both experimental and control groups.

Types of outcome measures

There is considerable variation in the outcome measures reported in clinical trials of interventions for pain. For the purpose of this systematic review, we aimed to include clinically important changes in pain, as recommended by the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT). Reductions in pain intensity of 30% or greater reflect moderate clinically important differences and 50% or greater reflect substantial clinically important differences, and it is recommended that the proportion of patients who respond with these degrees of pain relief be reported (Dworkin 2008).

Continuous outcome measures in pain trials (such as mean change on a 100 mm Visual Analogue Scale (VAS)) may not follow a Gaussian distribution. Often, a bimodal distribution is seen instead, where patients tend to report either very good or very poor pain relief (Moore 2010). This creates difficulty in interpreting mean changes in continuous pain measures. For this reason, a dichotomous outcome measure (the proportion of participants reporting 30% or greater pain relief) is likely to be more clinically relevant and was the main outcome measure of benefit in this review. However, it is recognised that it has been the practice in most trials of interventions for chronic pain to report continuous measures and, therefore, the mean pain score or mean change in pain score were also included as major outcomes.

The pain state at the end of a clinical trial of an analgesic intervention, in contrast to measures of pain improvement, has also been recommended as a clinically relevant dichotomous outcome measure and was included as a secondary efficacy measure in this review (Moore 2010). A global rating of treatment satisfaction, such as the Patient Global Impression of Change scale (PGIC), which provides an outcome measure that integrates pain relief, changes in function and adverse effects, into a single, interpretable measure, is also recommended by IMMPACT, and was included as a major outcome (Dworkin 2008).

Major outcomes

We presented the major outcomes below in the 'Summary of findings' tables.

Participant‐reported pain relief of 30% or greater.
Mean pain score, or mean change in pain score on VAS or Numerical Rating Scale (NRS) or categorical rating scale (in that order of preference).
Disability or function. Where trialists reported outcome data for more than one function scale, we extracted data on the scale that was highest on the following an a priori consensus‐based list:
- Shoulder Pain And Disability Index (SPADI);
- Shoulder Disability Questionnaire (SDQ);
- Constant score;
- Disabilities of the Arm, Shoulder and Hand (DASH);
- Health Assessment Questionnaire (HAQ);
- any other function scale.
Composite endpoints measuring 'success' of treatment such as participants feeling no further symptoms.
Quality of life.
Number of participant withdrawals, for example, due to adverse events or intolerance to treatment.
Number of participants experiencing any adverse event.

Minor outcomes

Proportion of participants achieving pain score below 30/100 mm on VAS.
ROM active preferred over passive measures: shoulder abduction, flexion, external rotation and internal rotation (measured in degrees or other; e.g. hand‐behind‐back distance in centimetres).
For participants with calcification, the effect of ESWT on the size of the calcification.
For participants with calcific deposits, the number of participants with complete or partial resolution (defined or not) of calcific deposits.

We extracted outcome measures assessing benefits of treatment (e.g. pain, function, success, quality of life) at the time points:

up to six weeks;
greater than six weeks to three months (this was the primary time point);
greater than three months to up to six months;
greater than six months to 12 months;
greater than 12 months.

If data were available in a trial at multiple time points within each of the above periods (e.g. at four, five and six weeks), we only extracted data at the latest possible time point of each period. We extracted adverse events, calcification resolution and treatment success at the end of the trial.

Search methods for identification of studies

Electronic searches

We searched the following electronic databases, unrestricted by date or language, on 11 November 2019:

the Cochrane Central Register of Controlled Trials (CENTRAL, via the Cochrane Library);
MEDLINE (Ovid);
Embase (Ovid);
ClinicalTrials.gov;
World Health Organization (WHO) International Clinical Trials Registry Platform.

For the database searches, we combined search terms and text words describing rotator cuff disease and ESWT for the CENTRAL search (Appendix 1), and with validated methodological filters designed to identify CCTs for the MEDLINE database (Appendix 2) (Lefebvre 2011), and the Embase database (Appendix 3). We searched ClinicalTrials.gov (Appendix 4) and the WHO International Clinical Trials Registry Platform (www.who.int/trialsearch/Default.aspx) (Appendix 5) for ongoing trials.

Searching other resources

We checked reference lists of all included articles for additional references.

Data collection and analysis

Selection of studies

Two review authors (SJS, JD) independently selected the trials to be included in the review and retrieved all articles selected by at least one of the review authors for further examination. The review authors were not blinded to the journal or authors. A third review author (RJ) resolved disagreement about inclusion or exclusion of individual studies.

Data extraction and management

Two review authors (SJS, JD) independently extracted data using a standard data extraction form developed for this review. The authors resolved any discrepancies through discussion or adjudication by a third author (RJ or RB), until we reached consensus. We pilot tested the data extraction form and modified it accordingly before use. In addition to items for assessing risk of bias and numerical outcome data, we extracted the following data.

Trial characteristics, including type (e.g. parallel or cross‐over), country, source of funding and trial registration status (with registration number recorded if available).
Participant characteristics, including age, sex, duration of symptoms and inclusion/exclusion criteria.
Intervention characteristics, including description of modality used, dose of treatment, method of administration, frequency of administration and use of co‐interventions.
Outcomes reported, including measurement instrument used and timing of outcome assessment.

Two review authors (SJS, JD) each independently compiled half of the comparisons and entered outcome data into Review Manager 5 (Review Manager 2014). The two review authors (SJS, JD) then independently checked the other author's work to ensure all data were accurate.

For a particular systematic review outcome there may be a multiplicity of results available in the trial reports (e.g. multiple scales, time points and analyses). To prevent selective inclusion of data based on the results (Page 2015), we used the following a priori defined decision rules to select data from trials.

Where trialists reported both final values and change from baseline values for the same outcome, we extracted final values.
Where trialists reported both unadjusted and adjusted values for the same outcome, we extracted unadjusted values.
Where trialists reported data analysed based on the intention‐to‐treat (ITT) sample and another sample (e.g. per‐protocol, as‐treated), we extracted ITT‐analysed data.
For cross‐over RCTs, we extracted data from the first period only.

Where trials did not include a measure of overall pain but included one or more other measures of pain, for the purpose of combining data for the primary analysis of overall pain, we combined overall pain with other types of pain in the following hierarchy:

overall or unspecified pain;
pain at rest;
pain with activity;
daytime pain;
night‐time pain.

Where trials included more than one measure of disability or function, we extracted data from the one function scale that was highest on the following a priori defined list:

SPADI;
SDQ;
Constant score;
DASH;
HAQ;
any other function scale.

Where trials included more than one measure of treatment success, we extracted data from the one function scale that was highest on the following a priori defined list:

participant‐defined measures of success, such as asking participants if treatment was successful;
trialist‐defined measures of success, such as a 30‐point increase on the Constant Score.

For ROM, we only extracted active ROM (abduction or flexion) measured in number of degrees.

Assessment of risk of bias in included studies

Three review authors (SJS, JD, RJ) independently assessed the risk of bias of each included study. The authors resolved any discrepancies through discussion or adjudication by a fourth author (RB), until consensus was reached.

We assessed the following methodological domains, as recommended by Cochrane (Higgins 2011a):

sequence generation (to determine if the method of generating the randomisation sequence was adequate, such as random‐number tables, computer‐generated random numbers, minimisation, coin tossing, shuffling of cards and drawing of lots);
allocation sequence concealment (to determine if adequate methods were used to conceal allocation, such as central randomisation and sequentially numbered, sealed, opaque envelopes);
blinding of participants and personnel;
blinding of outcome assessors: we considered blinding of assessors of self‐reported subjective outcomes (pain, function, success, quality of life) separately from assessors of more objective outcomes (such as calcification and adverse events);
incomplete outcome data;
selective outcome reporting;
other potential threats to validity including baseline imbalance, unit of analysis issues, inappropriate or unequal application of co‐interventions across treatment groups.

Measures of treatment effect

When possible, we based analyses on ITT data (outcomes provided for every randomised participant) from the individual trials. For each trial, we presented outcome data as point estimates with mean and standard deviation (SD) for continuous outcomes and risk ratios (RRs) with corresponding 95% confidence interval (CI) for dichotomous outcomes. Where possible, for continuous outcomes, we extracted end of treatment scores, rather than change from baseline scores.

For continuous data, we presented results as mean differences (MD), if possible. When studies used different scales to measure the same conceptual outcome (e.g. disability), we calculated standardised mean differences (SMD), with corresponding 95% CI. SMD was back‐translated to a typical scale (e.g. 0 to 10 for pain) by multiplying the SMD by a typical among‐person SD (e.g. the SD of the control group at baseline from the most representative trial) (Schünemann 2011a). For ESWT versus placebo, we converted pain (Analysis 1.2) to a 0‐ to 10‐point VAS score using the SD reported at baseline in the placebo group from Gerdesmeyer 2003 (mean (SD): 5.1 (1.6)). For ESWT versus placebo, we converted function (Analysis 1.3) to a 0‐ to 100‐point Constant scale using the SD reported at baseline in the placebo group from Gerdesmeyer 2003 (mean (SD): 64.2 (12.8)). For high‐dose versus low‐dose ESWT, we converted pain (Analysis 8.1) to a 0‐ to 10‐point VAS score using the SD reported at baseline in the placebo group from Gerdesmeyer 2003 (mean (SD): 5.1 (1.6)). For high‐dose versus low‐dose ESWT, we converted function (Analysis 8.2) to a 0‐ to 100‐point Constant scale using the SD reported at baseline in the placebo group from Gerdesmeyer 2003 (mean (SD): 64.2 (12.8)).

In the 'Comments' column of the 'Summary of findings' table, we reported the absolute percent difference and the relative percent change from baseline.

For dichotomous outcomes, we calculated the absolute risk difference using the risk difference statistic in Review Manager 5 (Review Manager 2014), and the result expressed as a percentage. For continuous outcomes, we calculated the absolute benefit as the improvement in the intervention group minus the improvement in the control group (MD), in the original units, and expressed as a percentage.

We calculated the relative percent change for dichotomous data as the RR – 1 and expressed as a percentage. For continuous outcomes, we calculated the relative difference as the absolute benefit divided by the baseline mean of the control group, expressed as a percentage.

Unit of analysis issues

Where a single trial reported multiple trial arms, we included only the relevant arms. For the comparison, ESWT versus placebo, if two different energy doses of shock wave therapy and a placebo or control arm were included in a three arm trial (Gerdesmeyer 2003; Peters 2004), we chose the lower dose shock wave therapy as the shock wave arm and compared this to placebo to avoid the data for that study population being over‐represented in the meta‐analysis. The rationale for choosing the lower dose was to reduce clinical heterogeneity within the meta‐analysis, as the lower dose seemed closer to the dose used in the active treatment group of the two arm trials, and there did not appear to be consensus for a definition of a clinical therapeutic dose.

Two trials treated two shoulders in a single participant without adjusting their analysis for the lack of independence (Pan 2003; Pleiner 2004). We reported this as a potential source of additional bias and assessed the impact of including these trials in a sensitivity analysis. When the data for these studies was extracted, the number of shoulders was taken as the population for the study.

If we had identified cross‐over trials, we planned to extract data from the first phase of the trial to avoid potential carry over effects. If we had identified cluster‐randomised trials that did not adjust for potential unit of analysis issues, we would note this and assess the effect of including studies with potential unit of analysis issues in a sensitivity analysis.

Dealing with missing data

Where data were missing or incomplete, we sought further information from the study authors.

In cases where participants were missing from the reported results, we assumed the missing values to have a poor outcome. For dichotomous outcomes that measured adverse events (e.g. number of withdrawals due to adverse events), we calculated the withdrawal rate using the number of participants who received treatment as the denominator (worst‐case analysis). For dichotomous outcomes that measured benefits (e.g. proportion of participants with 30% or more reduction in pain), we calculated the worst‐case analysis using the number of randomised participants as the denominator. For continuous outcomes (e.g. pain), we calculated the MD or SMD based on the number of participants analysed at the time point. If the number of participants analysed were not presented for each time point, we used the number of randomised participants in each group at baseline.

Where possible, we computed missing SDs from other statistics such as standard errors, CIs or P values, according to the methods recommended in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011b). If SDs could not be calculated, they were imputed (e.g. from other studies in the meta‐analysis (Higgins 2011c).

Assessment of heterogeneity

We assessed clinical heterogeneity by determining whether the characteristics of participants, interventions, outcome measures and timing of outcome measurement were similar across trials. We assessed statistical heterogeneity using the Chi² statistic and the I² statistic (Higgins 2002). We interpreted the I² statistic using the following as an approximate guide.

0% to 40% may not be important heterogeneity.
30% to 60% may represent moderate heterogeneity.
50% to 90% may represent substantial heterogeneity.
75% to 100% may represent considerable heterogeneity (Deeks 2011).

Assessment of reporting biases

To determine whether reporting bias was present, we determined whether the protocol of the RCT was published before recruitment of participants of the study was started. For studies published after 1 July 2005, we screened the WHO International Clinical Trials Registry Platform (apps.who.int/trialssearch). We evaluated whether selective reporting of outcomes was present (outcome reporting bias).

We compared the fixed‐effect estimate against the random‐effects model to assess the possible presence of small‐sample bias in the published literature (i.e. in which the intervention effect is more beneficial in smaller studies). In the presence of small‐sample bias, the random‐effects estimate of the intervention is more beneficial than the fixed‐effect estimate (Sterne 2011).

The potential for small‐study effects in the main outcomes of the review were further explored using funnel plots if at least 10 studies were included in a meta‐analysis for the main efficacy outcome.

Data synthesis

For clinically similar studies that used a common comparator, we pooled outcomes in a meta‐analysis using the random‐effects model as a default, and performed a sensitivity analysis with the fixed‐effect model.

'Summary of findings' table

We created a 'Summary of findings' table using the following outcomes: pain relief greater than 50% (the a priori outcome was pain relief of 30% or greater, which none of the studies reported so we reported pain relief greater than 50%), mean pain score, function, participant‐reported success, quality of life, number of participant withdrawals due to adverse events or treatment intolerance, and number of participants experiencing any adverse event. We selected three months as the primary time point (for the outcomes assessing benefits of treatment) and placebo as the main comparator.

All review authors independently assessed the certainty of the evidence. We used the five GRADE considerations (study limitations, consistency of effect, imprecision, indirectness and publication bias) to assess the certainty of the body of evidence as it related to the studies which contribute data to the meta‐analyses for the prespecified outcomes. We used methods and recommendations described in Section 8.5, Section 8.7, Chapter 11 and Section 13.5 of the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011a; Reeves 2011; Schünemann 2011b) using GRADEpro software (GRADEpro GDT 2015). We justified all decisions to downgrade the certainty of the studies using footnotes and made comments to aid the reader's understanding of the review where necessary.

Subgroup analysis and investigation of heterogeneity

We planned to carry out the following subgroup analyses:

those with and without calcification.

We used the following outcomes in subgroup analyses, for the main comparison (ESWT versus placebo):

pain;
function.

Sensitivity analysis

We performed the following sensitivity analyses for the main comparator (ESWT vs placebo), for the outcomes pain and function:

adequate allocation concealment (selection bias);
participant blinding (detection bias).

We removed the trials that reported inadequate or unclear allocation concealment and lack of participant blinding from the meta‐analysis of pain and function for the main comparison (ESWT versus placebo), at the primary time point (three months) to assess the effect of potential selection and detection biases on the overall treatment effect.

Results

Description of studies

Results of the search

The database searches conducted up to 11 November 2019 resulted in retrieval of 461 records. After removal of duplicates, 285 unique records remained. After screening the abstracts, we retrieved 104 unique studies for full‐text screening, out of which we excluded 58 studies (see Characteristics of excluded studies table). We selected 32 trials for inclusion (Albert 2007; Cacchio 2006; Cosentino 2003; De Boer 2017; Del Castillo‐Gonzales 2016; Duymaz 2019; Engebretsen 2009; Farr 2011; Frizziero 2017; Galasso 2012; Gerdesmeyer 2003; Haake 2002; Hearnden 2009; Hsu 2008; Ioppolo 2012; Kim 2014; Kolk 2013; Kvalvaag 2017; Li 2017; Loew 1999; Melegati 2000; Pan 2003; Perlick 2003; Peters 2004; Pleiner 2004; Rompe 1998; Sabeti 2007; Sabeti‐Aschraf 2005; Schmitt 2001; Schofer 2009; Speed 2002; Tornese 2011; Characteristics of included studies table). Nine additional trials are awaiting classification, as they could not be translated (Berner 2004; Diehl 2011; Gross 2002; Loew 1995; Mao 2003; Paternostro‐Sluga 2004; Rompe 1997a; Rompe 1997b; Seil 1999; Characteristics of studies awaiting classification table). We identified five ongoing trials in clinical trials registries (ChiCTR1900022932; NCT02677103; NCT03779919; NTR7093; PACTR201910650013453; Characteristics of ongoing studies table). Figure 1 shows the flow diagram of the study selection process.

Figure 1

Study flow diagram.

Included studies

A full description of all included trials is provided in the Characteristics of included studies table. We contacted authors of 24 trials to request information about study design, participants, interventions and outcomes of the trial; information required to complete the risk of bias assessments; or missing data for unreported or partially reported outcomes (Albert 2007; Cacchio 2006; Cosentino 2003; Engebretsen 2009; Farr 2011; Frizziero 2017; Galasso 2012; Gerdesmeyer 2003; Haake 2002; Hearnden 2009; Hsu 2008; Ioppolo 2012; Kim 2014; Kolk 2013; Loew 1999; Melegati 2000; Pan 2003; Perlick 2003; Peters 2004; Pleiner 2004; Rompe 1998; Sabeti‐Aschraf 2005; Sabeti 2007; Tornese 2011). We received replies from five trialists (Engebretsen 2009; Frizziero 2017; Galasso 2012; Kolk 2013; Sabeti 2007).

Study design and setting

All studies were parallel‐group RCTs. Twenty‐eight trials included two intervention arms, three trials included three intervention arms (Peters 2004; Gerdesmeyer 2003; Melegati 2000), and one trial included four intervention arms (Loew 1999).

Trials were set in Italy (Cacchio 2006; Cosentino 2003; Frizziero 2017; Galasso 2012; Ioppolo 2012; Melegati 2000; Tornese 2011), Germany (Haake 2002; Loew 1999; Perlick 2003; Peters 2004; Rompe 1998; Schmitt 2001; Schofer 2009), Austria (Farr 2011; Pleiner 2004; Sabeti 2007; Sabeti‐Aschraf 2005), Germany and Austria (Gerdesmeyer 2003), Norway (Engebretsen 2009; Kvalvaag 2017), the Netherlands (De Boer 2017; Kolk 2013); UK (Hearnden 2009; Speed 2002), China (Hsu 2008; Li 2017), France (Albert 2007), Taiwan (Pan 2003), Spain (Del Castillo‐Gonzales 2016), Turkey (Duymaz 2019), and South Korea (Kim 2014).

Two studies were funded by manufacturers of shock wave machines (Galasso 2012; Kolk 2013), seven studies were funded by grants from research foundations or universities (Albert 2007; Del Castillo‐Gonzales 2016; Engebretsen 2009; Gerdesmeyer 2003; Ioppolo 2012; Kvalvaag 2017; Li 2017), three studies were provided with the shock wave machines (Albert 2007; Gerdesmeyer 2003; Pleiner 2004), nine studies explicitly reported they received no funding (Cacchio 2006; Duymaz 2019; Hearnden 2009; Kim 2014; Loew 1999; Pan 2003; Schmitt 2001; Speed 2002; Tornese 2011), while 13 studies did not report either way (Cosentino 2003; De Boer 2017; Farr 2011; Frizziero 2017; Haake 2002; Hsu 2008; Melegati 2000; Perlick 2003; Peters 2004; Rompe 1998; Sabeti 2007; Sabeti‐Aschraf 2005; Schofer 2009).

Participant characteristics

The 32 trials included 2281 participants, and the number of participants per trial ranged from 20 to 243. Of the 16 studies that reported mean age of the overall cohort, the mean age of participants ranged from 48 years to 56.2 years. Of the seven studies that reported the mean duration of symptoms of the overall cohort, the mean duration of symptoms ranged from 7.1 to 60 months. Of the 30 studies that reported population gender numbers, 61% of participants were female.

Inclusion criteria or definitions of the included conditions (or both) varied between trials. Ten trials specified calcific or calcifying tendonitis or tendinopathy without specifying the involved tendons (Albert 2007; Cacchio 2006; Duymaz 2019; Farr 2011; Gerdesmeyer 2003; Haake 2002; Hsu 2008; Pan 2003; Sabeti‐Aschraf 2005; Tornese 2011); 11 trials specified the presence of symptoms such as pain (De Boer 2017; Del Castillo‐Gonzales 2016; Duymaz 2019; Frizziero 2017; Haake 2002; Hsu 2008; Kvalvaag 2017; Peters 2004; Pleiner 2004; Rompe 1998; Sabeti‐Aschraf 2005), four trials specified supraspinatus or infraspinatus calcification (Cosentino 2003; Hearnden 2009; Kim 2014; Sabeti 2007), two trials specified non‐calcific tendonitis of the supraspinatus tendon (Schmitt 2001; Schofer 2009), two trials specified non‐calcific tendonitis of any part of the rotator cuff (Galasso 2012; Speed 2002), four trials specified calcific deposits without tendonitis (De Boer 2017; Del Castillo‐Gonzales 2016; Ioppolo 2012; Kim 2014), two trials specified subacromial shoulder pain (Engebretsen 2009; Kvalvaag 2017), two trials included shoulder pain without a specified location (Loew 1999; Perlick 2003), one trial specified subacromial impingement syndrome (Melegati 2000), and two trials specified chronic tendonitis (Kolk 2013; Li 2017). Twenty trials included radiographic imaging as part of their definition for the condition (Albert 2007; Cacchio 2006; Cosentino 2003; De Boer 2017; Frizziero 2017; Gerdesmeyer 2003; Haake 2002; Hearnden 2009; Ioppolo 2012; Kim 2014; Melegati 2000; Pan 2003; Perlick 2003; Peters 2004; Pleiner 2004; Rompe 1998; Sabeti 2007; Sabeti‐Aschraf 2005; Speed 2002; Tornese 2011).

Twenty‐three trials only included participants with calcific tendinitis (Albert 2007; Cacchio 2006; Cosentino 2003; De Boer 2017; Del Castillo‐Gonzales 2016; Duymaz 2019; Farr 2011; Gerdesmeyer 2003; Haake 2002; Hearnden 2009; Hsu 2008; Ioppolo 2012; Kim 2014; Kvalvaag 2017; Loew 1999; Pan 2003; Perlick 2003; Peters 2004; Pleiner 2004; Rompe 1998; Sabeti 2007; Sabeti‐Aschraf 2005; Tornese 2011), seven trials only included participants without calcific deposits (Frizziero 2017; Galasso 2012; Li 2017; Melegati 2000; Schmitt 2001; Schofer 2009; Speed 2002), and two trials included participants with or without calcific deposits (Engebretsen 2009; Kolk 2013). Only Kolk 2013 reported data for participants with and without calcific deposits separately.

Interventions

A detailed description of the interventions delivered in each trial is summarised in the Characteristics of included studies table and a summary of the shock wave technique and comparison tested in each trial is presented in Table 1. Shock wave treatments were very heterogeneous across trials and varied in the machines used to generate the shock waves, number and size of energy pulses, and the number of treatment sessions (one to six sessions varying from seven to 16 days apart).

See: Summary of findings for the main comparison Shock wave therapy versus placebo for rotator cuff disease with or without calcification

Table 1. Characteristics of interventions used in included trials

Study ID	Shock wave machine	Type of shock wave	Number, frequency and dose	Comparison	Use of anaesthesia	Number of treatments
Albert 2007	Modulith SLK (Storz Medical AG, Tagerwilen, Switzerland) electromagnetic shock wave generator with fluoroscopic and sonographic guidance	ESWT	High‐dose shock wave: 2500 impulses, frequency 1 Hz for first 200 and 2 Hz thereafter. Goal intensity was maximum energy level tolerated by participant without exceeding 0.45 mJ/mm² per impulse	Low dose: 2500 impulses, frequency 1 Hz for first 200 and 2Hz thereafter. The energy intensity gradually increased from 0.02 mJ/mm² to 0.06 mJ/mm² per shock	None	2 sessions 14 days apart
Cacchio 2006	Physio Shock Wave Therapy device consisting of a control unit, a handpiece with 3 different head applicators and medical air compressor	rESWT	High dose: 2500 impulses per session (500 impulses with pressure 1.5 bar and frequency 10 Hz), EFD 0.10 mJ/mm² and fixed impulse time of 2 ms	Low dose: 25 impulses per session (5 impulses with a pressure of 1.5 bar and frequency of 4.5 Hz and 20 impulses with pressure 2.5 bar and frequency 10 Hz), EFD 0.10 mJ/mm² and fixed impulse time of 2 ms	None	4 sessions 7 days apart
Cosentino 2003	'Orthima' by Direx Medical System Ltd	ESWT	Shock wave: 1200 shocks at 120 shocks/minute of 0.03 mJ/mm²	Placebo: 1200 shocks at 120 shock/minute of 0 mJ/mm²	None	4 sessions 4–7 days apart
De Boer 2017	Masterpuls MP 100 (Storz Medical, Tagerwilen, Switzerland)	rESWT	Shock wave: 500 pulses of 1.5 bar (150 kPa) with a frequency of 4.5 Hz, followed by 2000 pulses of 2.5 bar (250 kPa) with a frequency 10 Hz; EFD)0.10 mJ/mm², duration of pulses was 2 ms	Ultrasound‐guided needling	None	4 sessions, 1 week apart
Del Castillo‐Gonzales 2016	Swiss DolorClast device	ESWT	Shock wave: Total of 2000 impacts (2 series of 1000 each) at frequency 8–10 Hz and EFD 0.20 J/mm²	Ultrasound‐guided percutaneous lavage	None	Twice per week for 4 weeks
Duymaz 2019	ShockMaster 500 device (GymnaUniphy NV, Bilzen, Belgium)	rESWT	Shock wave: 1500 shocks with a frequency of 150 shocks per minute. all participants were treated with a low‐energy density of 0.03 mJ/mm² for the first 5 minutes, which was then progressively increased to 0.28 mJ/mm². Duration of pulses was 10 minutes	Physiotherapy: ultrasound (1.0 MHz, 5 minutes, continuous), TENS (conventional, 20 minutes), shoulder joint ROM and stretching exercises, and ice application	None	1 session weekly for 4 weeks
Engebretsen 2009	Swiss Dolor Clast, EMS	rESWT	Shock wave: 8–12 Hz at 2000 impulses/second with a pressure of 2.5–4.0 bar	Supervised exercises	None	1 session weekly for 4–6 weeks for rESWT OR 2 × 45‐minute sessions weekly for up to 12 weeks for supervised exercises
Farr 2011	Storz Modulith SLK lithotripter in combination with a fluoroscopy‐guided 3D computer‐assisted navigation device	ESWT	High dose: 3200 impulses at 0.3 mJ/mm²; twice	Low dose: 1600 impulses at 0.02 mJ/mm²; once	5 mL xylocaine subacromially	Once only for low dose OR 2 sessions 7 days apart for high dose
Frizziero 2017	Modulith SLK (Storz Medical AG, Tagerwilen, Switzerland)	ESWT	Shock wave (low dose): 1600 impulses at a frequency of 4 Hz not exceeding 0.15 mJ/mm²	Ultrasound‐guided injection with low molecular weight hyaluronic acid	None	Weekly shock wave sessions for 4 weeks OR 1 injection weekly for 3 weeks
Galasso 2012	Modulith SLK system	ESWT	Shock wave: 3000 shocks of 0.068 mJ/mm²	Placebo: Same protocol but with shock wave generator disconnected	Subcutaneous injection of 2 mL of 2% lidocaine above the subacromial space of the affected shoulder prior to each treatment	2 sessions 7 days apart
Gerdesmeyer 2003	Not reported	ESWT	Shock wave (low dose): 6000 shocks at 120 impulses/minute of 0.08 mJ/mm²	High dose: 6000 shocks at 120 impulses/minute of 0.32 mJ/mm² OR Placebo: 1500 shocks at 120 impulses/minute of 0.32 mJ/mm² with participant insulated from shock waves	None	2 sessions 12–16 days apart
Haake 2002	Adapted shock wave generator Storz Minilith SL‐1 (Storz Medical AG, CH 8280 Kreuzlingen, Switzerland)	ESWT	At site of calcification: 2000 impulses of a positive EFD 0.35 mJ/mm² measured with a membrane hydrophone (equivalent to 0.78 mJ/mm² measured with a fibreoptic hydrophone) at 120 impulses/minute	Supraspinatus site: 2000 impulses of a positive EFD 0.35 mJ/mm² measured with a membrane hydrophone (equivalent to 0.78 mJ/mm² measured with a fibreoptic hydrophone) at 120 impulses/minute	15 mL mepivacaine 1% subacromially	2 sessions 7 days apart
Hearnden 2009	Not reported	ESWT	Shock wave: 2000 shocks of 0.28 mJ/mm²	Placebo: 20 shocks of 0.03 mJ/mm²	20 mL of 0.5% marcaine at site of calcific deposit	1 session
Hsu 2008	OrthoWave machine (MTS, Konstanz, Germany)	ESWT	Shock wave: 1000 shocks at 2 wave pulses/second of 0.55 mJ/mm²	Placebo: dummy electrode	10 mL of 2% lidocaine injected into affected area from a lateral approach with a 24‐gauge needle	2 sessions 14 days apart
Ioppolo 2012	ESWT (Modulith SLK system, Storz Medical, Tager‐wilen, Switzerland) equipped with an in‐line ultrasound positioning system on the target zone	ESWT	Low dose: 2400 impulses at 0.10 mJ/mm²	High dose: 2400 impulses at 0.20 mJ/mm²	None	4 sessions 7 days apart
Kim 2014	Not reported	ESWT	Shock wave: 1000 impulses, 0.32 mJ/mm²	Glucocorticoid needling 1 mL Depo‐Medrol (glucocorticoid) ultrasound guidance	2% lidocaine in the corticosteroid group	3 sessions 1 week apart for ESWT OR 1 steroid injection
Kolk 2013	Swiss DolorClast radial shock wave device (EMS Electro Medical Systems, Nyon, Switzerland)	rESWT	Shock wave: 2000 impulses of 0.11 mJ/mm²	Placebo: 2000 impulses of 0.11 mJ/mm² with a sham probe	None	3 sessions 10–14 days apart
Kvalvaag 2017	EMS Swiss DolorClast/Enimed	rESWT	Shock wave: 2000 impulses at 0.35 mJ/mm² pressure 1.5–3 bar, depending on what the participant tolerated	Placebo: 2000 impulses at 0.35 mJ/mm² with a sham probe	None	1 session weekly for 4 weeks
Li 2017	Pain Treatment System of Radial shock wave Device (Sonothera, Hanil Tm Co. Ltd, Korea)	ESWT	Shock wave: 3000 pulses of 0.11 mJ/mm² at frequency 15 Hz. Pressure 3 bar	Placebo: identical‐looking placebo probe used	None	5 sessions, 3 days apart
Loew 1999	Electrohydraulic lithotripter (MFL 5000; Philips, Hamburg, Germany)	ESWT	Group 1: 1 dose of 2000 impulses of 0.1 mJ/mm² Group 2: 1 dose of 2000 impulses of 0.3 mJ/mm² Group 3: 2 doses of 2000 impulses of 0.3 mJ/mm² 1 week apart	No treatment	15–20 mL bupivacaine hydrochloride	1 session OR 2 sessions 1 week apart
Melegati 2000	Epos Ultra electromagnetic apparatus fitted with a 7.5 MHz linear echographic sound	ESWT	200 shots of 0.22 mJ/mm² reached in 400 shots	Kinesitherapy	None	3 sessions 7 days apart for ESWT OR 6 × 40‐minute sessions 3 weeks apart for kinesitherapy
Pan 2003	Orthospec (Medispec Ltd, Germantown, MD, USA)	ESWT	2000 shock waves at 2 Hz of 0.26–0.32 mJ/mm²	TENS	None	2 sessions 14 days apart for ESWT OR 3 times a week for 4 weeks for TENS
Perlick 2003	Siemens Lithostar‐Lithotripter	ESWT	2000 impulses of 0.23 mJ/mm²	2000 impulses of 0.42 mJ/mm²	10 mL bupivacaine hydrochloride 0.5%	2 sessions 3 weeks apart
Peters 2004	The miniaturised shock wave source Minilith (15 cm diameter, 15 cm length) (Stroz Medical, Switzerland) with an in‐line ultrasound device	ESWT	1500 impulses of 0.15 mJ/mm²	1500 impulses of 0.44 mJ/mm² OR system turned off	None	1–5 sessions at 6‐week intervals
Pleiner 2004	Electrohydraulic system (Orthospec, Medispec Inc, Montgomery Village, MD, USA)	ESWT	High dose: 2 × 2000 impulses at frequency 2.5 Hz, dose 0.28 mJ/mm²	Placebo 2 × 2000 impulses at frequency 2.5 Hz, dose < 0.07 mJ/mm² dampened with a foam membrane	None	2 sessions
Rompe 1998	ESWT with an experimental device characterised by the integration of an electromagnetic shock wave generator and a mobile fluoroscopy unit (Siemens AG, 91052 Erlangen, Germany)	ESWT	1500 impulses of 0.06 mJ/mm²	1500 impulses of 0.28 mJ/mm²	None	1 session
Sabeti 2007	Lithotripter (Storz Modulith SLK, Storz Medical Products, Kreuzlingen, Switzerland)	ESWT	1000 impulses of 0.08 mJ/mm²	2000 impulses of 0.02 mJ/mm²	5 mL Xyloneural subacromially	3 sessions 7 days apart for low dose OR 2 sessions 7 days apart for higher dose
Sabeti‐Aschraf 2005	Lithotripter (Modulith SLK, Storz Medical Products, Kreuzlingen, Switzerland)	ESWT	1000 impulses of 0.08 mJ/mm² with frequency 4 Hz	1000 impulses of 0.08 mJ/mm² with frequency 4 Hz	None	3 sessions 7 days apart
Schmitt 2001	Storz Minilith SL 1 (Storz Medical AG, Kreuzlingen, Switzerland)	ESWT	2000 impulses at 120 impulses/minute of 0.11 mJ/mm²	2000 impulses at 120 impulses/minute of 0.11 mJ/mm² with the participant insulated from the shock waves	10 mL mepivacaine subacromially	3 sessions 7 days apart
Schofer 2009	Minilith SL 1 shock wave generator (Storz Medical, Switzerland)	ESWT	2000 impulses at 120 impulses/second of 0.33 mJ/mm²	2000 impulses at 120 impulses/second of 0.78 mJ/mm²	10 mL mepivacaine 1% subacromially	3 sessions 7 days apart
Speed 2002	Sonocur Plus Unit (Siemens, Munich, Germany)	ESWT	1500 impulses of 0.12 mJ/mm²	1500 impulses of 0.04 mJ/mm² with the machine head deflated, no contact gel applied and standard skin contact avoided	None	3 sessions 1 month apart
Tornese 2011	Electromagnetic lithotriptor (Epos Ultra; Dornier MedTech Wessling, Germany) fitted with a linear ultrasonographic probe	ESWT	1800 pulses of up to 0.22 mJ/mm² which was reached within 400 impulses	1800 pulses of up to 0.22 mJ/mm² which was reached within 400 impulses	None	3 sessions 7 days apart

EFD: energy fluctuation density; ESWT: extracorporeal shock wave therapy; rESWT: radial extracorporeal shock wave therapy; ROM: range of movement; TENS: transcutaneous electrical nerve stimulation.

Twelve trials compared ESWT to a placebo control (Cosentino 2003; Galasso 2012; Gerdesmeyer 2003; Hearnden 2009; Hsu 2008; Kolk 2013; Kvalvaag 2017; Li 2017; Peters 2004; Pleiner 2004; Schmitt 2001; Speed 2002). The trials the placebo control variably. Six trials used negligible or 0 mJ/mm² energy density (Cosentino 2003; Hearnden 2009; Hsu 2008; Kolk 2013; Peters 2004; Speed 2002), four trials physically blocked or dampened the shock waves (Gerdesmeyer 2003; Li 2017; Pleiner 2004; Schmitt 2001), one trial disconnected the shock wave device in the placebo group (Galasso 2012), and one trial did not clearly describe the sham procedure (Kvalvaag 2017).

Ten trials compared high‐dose to low‐dose ESWT (Albert 2007; Farr 2011; Gerdesmeyer 2003; Ioppolo 2012; Loew 1999; Perlick 2003; Peters 2004; Rompe 1998; Sabeti 2007; Schofer 2009), and one trial compared high‐dose to low‐dose RSWT (Cacchio 2006). Trials differed in their definition of high and low dose (Table 1).

One trial compared ESWT directed to the calcific deposit versus directed to the origin of the supraspinatus tendon (Haake 2002); one trial compared ESWT with the arm hyperextended versus with the arm in a neutral position (Tornese 2011); one trial compared fluoroscopic‐guided ultrasound targeted to the calcific deposit versus the shock waves directed to the area of maximum tenderness (Sabeti‐Aschraf 2005); one trial compared shock wave therapy plus physiotherapy to physiotherapy alone (Duymaz 2019); and one trial compared two versus one session of ESWT (Loew 1999).

Four trials compared ESWT to ultrasound‐guided needling (De Boer 2017; Del Castillo‐Gonzales 2016; Frizziero 2017; Kim 2014); one trial compared shock wave therapy to TENS (Pan 2003); ESWT to no treatment (Loew 1999); and combination of ESWT and exercise to exercise alone or advice alone (Melegati 2000). One trial compared RSWT to supervised exercise (Engebretsen 2009).

Outcomes

Of the major outcomes, no trial measured participant‐reported pain relief of 30% or greater or quality of life. However, one study reported participant‐reported pain relief of 50% or greater (Speed 2002); thus, we report this outcome as a major outcome.

Twenty‐nine trials measured pain (mean or mean change), with most using a 0‐ to 10‐point VAS with 10 indicating the worst pain. Of these, five partially reported the pain outcome (Cosentino 2003; Frizziero 2017; Hearnden 2009; Kim 2014; Speed 2002). Three trials did not measure the pain outcome (Loew 1999; Melegati 2000; Rompe 1998).

Thirty trials measured function, with the Constant score being the most commonly used. Of these, four trials partially reported the function outcome (Hearnden 2009; Kim 2014; Perlick 2003; Rompe 1998). Two trials did not measure function (Del Castillo‐Gonzales 2016; Peters 2004).

Fourteen trials measured treatment success using a variety of methods (Albert 2007; Cacchio 2006; De Boer 2017; Del Castillo‐Gonzales 2016; Galasso 2012; Gerdesmeyer 2003; Haake 2002; Hearnden 2009; Hsu 2008; Loew 1999; Peters 2004; Sabeti 2007; Schmitt 2001; Speed 2002).

Eight trials measured withdrawals due to adverse events (Engebretsen 2009; Gerdesmeyer 2003; Kolk 2013; Kvalvaag 2017; Li 2017; Peters 2004; Pleiner 2004; Speed 2002). Twenty‐seven trials measured adverse events (Albert 2007; Cacchio 2006; Cosentino 2003; De Boer 2017; Del Castillo‐Gonzales 2016; Engebretsen 2009; Farr 2011; Galasso 2012; Gerdesmeyer 2003; Haake 2002; Hearnden 2009; Hsu 2008; Ioppolo 2012; Kolk 2013; Kvalvaag 2017; Li 2017; Loew 1999; Pan 2003; Perlick 2003; Peters 2004; Pleiner 2004; Rompe 1998; Sabeti 2007; Sabeti‐Aschraf 2005; Schmitt 2001; Schofer 2009; Speed 2005), and of these one partially reported the adverse event outcome (Hearnden 2009). Five trials did not measure adverse events (Duymaz 2019; Frizziero 2017; Kim 2014; Melegati 2000; Tornese 2011)

We contacted authors of all trials who did not fully report outcomes to request missing data, and received missing data from two authors (Engebretsen 2009; Frizziero 2017). In two studies, it was possible to use alternate scores or extrapolation to extract the data for review (Kolk 2013; Sabeti 2007).

Of the minor outcomes, one trial measured pain below 30/100 on a VAS (Haake 2002), three trials measured active ROM (Cacchio 2006 measured active flexion; Duymaz 2019 measured flexion, extension, abduction and external rotation; and Engebretsen 2009 measured active abduction). Twenty‐one trials measured calcification size (mean size, mean change in size or disappearance/resolution of calcification) (Albert 2007; Cacchio 2006; Cosentino 2003; De Boer 2017; Del Castillo‐Gonzales 2016; Farr 2011; Gerdesmeyer 2003; Haake 2002; Hearnden 2009; Hsu 2008; Ioppolo 2012; Kim 2014; Loew 1999; Pan 2003; Perlick 2003; Peters 2004; Pleiner 2004; Rompe 1998; Sabeti 2007; Sabeti‐Aschraf 2005; Tornese 2011).

Excluded studies

A full description of all excluded trials is provided in the Characteristics of excluded studies table. Of the 58 full‐text articles excluded, 49 were not RCTs (Adamietz 2003; Astore 2003; Avancini‐Dobrovic 2011; Barnsley 2001; Boxberg 1996; Buch 1999; Buselli 2010; Bytomski 2006; Charrin 2001; Cheing 2003; Cosentino 2004; Costa 2002; Cyteval 2003; Friedberg 2010; Garcia Marti 2004; Hayes 2005; Jakobeit 2002; Labek 1999; Lee 2011; Lippincott 2010; Loew 1995; Lorbach 2008; Magosch 2003; Maier 2000; Mangone 2010; Manske 2004; Meier 2000; Moretti 2005; Mundy 2004; Noel 1999; Notarnicola 2011; Pigozzi 2000; Rebuzzi 2008; Rees 2009; Rompe 1995; Rompe 2000; Rompe 2001; Rompe 2003; Sabeti‐Aschraf 2004; Sarrat 2004; Seil 2006; Sistermann 1998; Speed 2005; Spindler 1998; Steinacker 2001; Thigpen 2010; Wang 2001; Wang 2003; Wiley 2002), four studies did not investigate shock wave therapy (Bringmann 2001; Krasny 2005; Polimeni 2003; Saggini 2010), four studies investigated conditions other than rotator cuff disease (Ali 2016; Chow 2007; Liu 2012; Njawaya 2018), and one study included postsurgical participants (Kim 2012).

Studies awaiting classification

Nine trials are awaiting classification, subject to translation into English (Berner 2004; Diehl 2011; Gross 2002; Loew 1995; Mao 2003; Paternostro‐Sluga 2004; Rompe 1997a; Rompe 1997b; Seil 1999; Characteristics of studies awaiting classification table).

Ongoing studies

At the time of publication of this review, there were five ongoing studies that did not have study results available at the time of submission of this review (ChiCTR1900022932; NCT02677103; NCT03779919; NTR7093; PACTR201910650013453). A description of these trials is provided in the Characteristics of ongoing studies table.

Risk of bias in included studies

All trials were susceptible to bias. Overall, 24/32 (75%) trials were susceptible to selection bias, 20 (62%) trials at risk of performance bias, 20 (62%) trials at risk of detection bias and 14 (45%) trials at risk of selective reporting bias (Figure 2).

Figure 2

Risk of bias summary: review authors' judgements about each risk of bias item for each included study.

Allocation

Only eight (26%) trials used appropriate methods to both generate and conceal their allocation sequence, and so were rated at low risk of selection bias (Albert 2007; Engebretsen 2009; Gerdesmeyer 2003; Hearnden 2009; Ioppolo 2012; Kvalvaag 2017; Li 2017; Schmitt 2001).

Ten (32%) trials did not clearly report their method of sequence generation (Cosentino 2003; Farr 2011; Kolk 2013; Loew 1999; Melegati 2000; Perlick 2003; Pleiner 2004; Rompe 1998; Sabeti‐Aschraf 2005; Speed 2002), and 24 (75%) trials did not adequately report their method of allocation concealment (Cacchio 2006; Cosentino 2003; De Boer 2017; Del Castillo‐Gonzales 2016; Duymaz 2019; Farr 2011; Frizziero 2017; Galasso 2012; Haake 2002; Hsu 2008; Kim 2014; Kolk 2013; Loew 1999; Melegati 2000; Pan 2003; Perlick 2003; Peters 2004; Pleiner 2004; Rompe 1998; Sabeti 2007; Sabeti‐Aschraf 2005; Schofer 2009; Speed 2002; Tornese 2011). Therefore, the risk of selection bias in these trials was unclear.

Blinding

We judged 12 (38%) trials at low risk of performance bias because participants and personnel were likely successfully blinded (Albert 2007; Cacchio 2006; Cosentino 2003; Galasso 2012; Haake 2002; Kolk 2013; Kvalvaag 2017; Li 2017; Pleiner 2004; Sabeti‐Aschraf 2005; Schmitt 2001; Schofer 2009). We judged five (15%) trials at high risk of performance bias as participants or personnel were not successfully blinded to treatment groups (De Boer 2017; Engebretsen 2009; Kim 2014; Loew 1999; Sabeti 2007).

In the remaining 15 trials (50%) the risk of performance bias was unclear as it was not clearly reported if personnel or participants, or both, were blinded (Del Castillo‐Gonzales 2016; Duymaz 2019; Farr 2011; Frizziero 2017; Gerdesmeyer 2003; Hearnden 2009; Hsu 2008; Ioppolo 2012; Melegati 2000; Pan 2003; Perlick 2003; Peters 2004; Rompe 1998; Speed 2002; Tornese 2011).

Twelve (38%) trials were at low risk of detection bias in self‐reported outcomes because participants were probably successfully blinded to treatment (Albert 2007; Cacchio 2006; Cosentino 2003; Galasso 2012; Haake 2002; Hearnden 2009; Kvalvaag 2017; Li 2017; Pleiner 2004; Sabeti‐Aschraf 2005; Schmitt 2001; Schofer 2009).

We judged 11 (32%) trials at unclear risk of detection bias due to lack of reporting of blinding methods (Duymaz 2019; Gerdesmeyer 2003; Ioppolo 2012; Kolk 2013; Melegati 2000; Perlick 2003; Peters 2004; Rompe 1998; Sabeti 2007; Speed 2002; Tornese 2011). We judged nine (29%) trials at high risk of detection bias as participants were either not blinded or likely guessed their treatment group due to the differing nature of the treatment groups (De Boer 2017; Del Castillo‐Gonzales 2016; Engebretsen 2009; Farr 2011; Frizziero 2017; Hsu 2008; Kim 2014; Loew 1999; Pan 2003).

Twenty‐seven trials included assessor‐rated outcomes (calcification size, ROM). There was a low risk of detection bias for these outcomes in 26 (84%) trials, as assessors were adequately blinded (Albert 2007; Cacchio 2006; Cosentino 2003; De Boer 2017; Del Castillo‐Gonzales 2016; Engebretsen 2009; Farr 2011; Frizziero 2017; Galasso 2012; Gerdesmeyer 2003; Haake 2002; Hsu 2008; Ioppolo 2012; Kolk 2013; Kvalvaag 2017; Li 2017; Melegati 2000; Pan 2003; Peters 2004; Pleiner 2004; Sabeti 2007; Sabeti‐Aschraf 2005; Schmitt 2001; Schofer 2009; Speed 2002; Tornese 2011). Outcome assessors were not blinded in one (3%) study, which was judged at high risk of detection bias (Loew 1999). It was unclear if assessors were blinded in five (15%) trials (Duymaz 2019; Hearnden 2009; Kim 2014; Perlick 2003; Rompe 1998).

Incomplete outcome data

We rated 22 (68%) trials at low risk of attrition bias because they had no dropouts or the losses to follow‐up, exclusions or attrition was sufficiently small that it was unlikely to have biased the results (Albert 2007; Duymaz 2019; Engebretsen 2009; Farr 2011; Frizziero 2017; Galasso 2012; Haake 2002; Hearnden 2009; Hsu 2008; Kvalvaag 2017; Li 2017; Loew 1999; Melegati 2000; Pan 2003; Perlick 2003; Peters 2004; Rompe 1998; Sabeti 2007; Sabeti‐Aschraf 2005; Schmitt 2001; Schofer 2009; Tornese 2011). In eight (26%) trials there was differential dropout across groups or reasons for drop out were related to treatment (e.g. no effect in placebo group) and thus we rated these trials as high risk of attrition bias (Cacchio 2006; Cosentino 2003; De Boer 2017; Del Castillo‐Gonzales 2016; Gerdesmeyer 2003; Ioppolo 2012; Kim 2014; Kolk 2013). The remaining two (6.4%) trials did not clearly report the amount of incomplete outcome data or reasons for incomplete outcome data so the risk of attrition bias was unclear (Pleiner 2004; Speed 2002).

Selective reporting

We rated 18 (56%) trials at low risk of selective reporting bias (Albert 2007; Cacchio 2006; Del Castillo‐Gonzales 2016; Duymaz 2019; Engebretsen 2009; Farr 2011; Frizziero 2017; Galasso 2012; Gerdesmeyer 2003; Haake 2002; Kolk 2013; Melegati 2000; Pan 2003; Pleiner 2004; Sabeti 2007; Sabeti‐Aschraf 2005; Schofer 2009; Tornese 2011). One trial reported all outcomes listed in the study protocol (Galasso 2012). One trial measured several outcomes which were not specified in the ClinicalTrials.gov registry but were added to the publication (e.g. function, active ROM, work status) (Engebretsen 2009). For the other 15 trials, while there was no published study protocol, results were reported for all outcomes measured (as stated in the methods) and included all major outcomes (except for quality of life, which no trial measured) sufficient for us to judge these as having a probable low risk of selective reporting bias (Albert 2007; Cacchio 2006; Del Castillo‐Gonzales 2016; Farr 2011; Frizziero 2017; Gerdesmeyer 2003; Haake 2002; Kolk 2013; Melegati 2000; Pan 2003; Pleiner 2004; Sabeti 2007; Sabeti‐Aschraf 2005; Schmitt 2001; Schofer 2009; Tornese 2011).

We rated four (13%) trials at unclear risk of selective reporting bias due to incomplete reporting of outcomes (Kvalvaag 2017; Li 2017; Schmitt 2001; Speed 2005). One study reported changes from baseline at the follow‐up (Li 2017). The trial protocol for Kvalvaag 2017 stated that return to work and health‐related quality of life were measured as secondary outcomes, but these outcomes were not reported in the results paper. Another trial had a significant number of unexplained dropouts without clear reporting of the number of participants who completed outcome measurements (Speed 2002). In one trial an outcome (treatment success) was possibly added post‐hoc (Schmitt 2001).

We rated 10 (32%) trials at high risk of selective reporting bias, as data were missing for one or more outcomes listed as measured in the methods (Cosentino 2003; De Boer 2017; Hearnden 2009; Loew 1999), or measures of variance were not reported for one or more outcomes (Hsu 2008; Ioppolo 2012; Kim 2014; Perlick 2003; Peters 2004; Rompe 1998).

Other potential sources of bias

Five (16%) trials were at high risk of other bias (De Boer 2017; Engebretsen 2009; Pan 2003; Pleiner 2004; Schmitt 2001). Two trials were at high risk of unit of analysis bias as trialists in both cases did not adjust for the non‐independence between groups due to bilateral treatment (Pan 2003; Pleiner 2004). One trial showed a high risk of bias as it was terminated prematurely because of higher pain in the shock wave group (De Boer 2017). Another trial was at high risk of bias because of imbalance between groups in the number of additional treatments received outside of the trial setting, which may have biased the results in favour of the radial extracorporeal shock wave therapy group (rESWT) (Engebretsen 2009). In another trial, 40% of participants were not satisfied with the allocated treatment and were unmasked and informed of their treatment group, and participants in the placebo group were offered shock wave therapy (Schmitt 2001). The remaining 26 (84%) trials were rated as being free from other potential sources of bias.

Effects of interventions

Shock wave therapy versus placebo

Twelve studies assessed shock wave therapy (using ESWT) compared to placebo (Cosentino 2003; Galasso 2012; Gerdesmeyer 2003; Hearnden 2009; Hsu 2008; Kolk 2013; Kvalvaag 2017; Li 2017; Peters 2004; Pleiner 2004; Schmitt 2001; Speed 2002).

Major outcomes

Participant‐reported pain relief of 30% or greater

The studies did not report pain relief of 30% or greater but did report pain relief of 50% or greater, which we report below.

Participant‐reported pain relief of 50% or greater

One study reported participant‐reported pain relief of 50% or greater at three months' follow‐up (Speed 2002). Speed 2002 reported that 14/34 participants in the ESWT group and 15/40 participants in the placebo group reported 50% or greater improvement in pain relief, a difference that was not statistically different, but of some uncertainty as it is based on low‐certainty evidence (RR 1.10, 95% CI 0.62 to 1.94; 74 participants), or in absolute terms, 4% more had pain relief (19% fewer to 26% more), and a relative change of 10% (38% fewer to 94% more) (summary of findings Table for the main comparison).

Mean pain

Six trials reported pain at zero to six weeks measured on two scales, a VAS score (Hsu 2008; Li 2017; Pleiner 2004; Schmitt 2001; Speed 2002) and Constant score (Galasso 2012). There was a small statistically significant but clinically uncertain reduction in pain with ESWT compared to placebo at six weeks' follow‐up (SMD –0.75, 95% CI –1.33 to –0.17; I² = 81%; 304 participants; Analysis 1.2). Based on an SD of 1.6 (Gerdesmeyer 2003), this was equivalent to a mean reduction of 1.2 points (95% CI –2.13 to –0.27) on a 0‐ to 10‐point VAS score, where 1.5 points is considered a clinically important difference in pain. Hsu 2008 found a large benefit in favour of shock wave therapy, which appears to be the main contributor to the large heterogeneity; removing data from Hsu 2008 removes the statistical heterogeneity (I² = 0%) without changing the direction of the effect (SMD –0.41, 95% CI –0.66 to –0.16; I² = 0%); this was equivalent to a pain reduction of 0.66 (95% CI –1.06 to –0.26 on a 0‐ to 10‐point scale).

Nine trials reported pain at six weeks to three months on two scales, a VAS score (Gerdesmeyer 2003; Hsu 2008; Kolk 2013; Kvalvaag 2017; Li 2017; Pleiner 2004; Schmitt 2001; Speed 2002) and Constant score (Galasso 2012). Low‐certainty evidence indicated a clinically unimportant reduction in pain with shock wave therapy compared to placebo (SMD –0.49, 95% CI –0.88 to –0.11; I² = 80%; 608 participants; Analysis 1.2). Based on an SD of 1.6 (Gerdesmeyer 2003), this translated to a mean improvement of 0.78 points (95% CI –1.4 to –0.17) on a 0‐ to 10‐point scale; or 7.8% improvement in pain (95% CI 2% to 14%), relative improvement of 14% (95% CI 3% to 25%) and number need to treat for an additional beneficial outcome (NNTB) of 4 (95% CI 2 to 34) (summary of findings Table for the main comparison).

The high heterogeneity was due to the large outlier reported in Hsu 2008; removing these data removed most heterogeneity (SMD –0.36, 95% CI –0.59 to –0.13; I² = 18%) (equivalent to a mean reduction of 0.58 points, 95% CI –0.94 to –0.21 on a 0 to 10 scale).

Five trials reported pain at three to six months using a 0‐ to 10‐point VAS score (higher score indicating more pain) (Gerdesmeyer 2003; Hsu 2008; Kolk 2013; Kvalvaag 2017; Speed 2002). There was no evidence of a between‐group difference in pain (MD ‐1.53, 95% CI ‐3.49 to 0.43) I² = 90%; 419 participants; Analysis 1.2).

Three trials reported pain at six to 12 months using a 0‐ to 10‐point VAS score (higher score indicating more pain) (Gerdesmeyer 2003; Hsu 2008; Pleiner 2004). There was no evidence of a between‐group difference in pain (MD –2.42, 95% CI –5.79 to 0.95; I² = 95%; 155 participants; Analysis 1.2). The high heterogeneity was due to the large outlier reported in Hsu 2008; removing these data removed all heterogeneity (MD –0.75, 95% CI –1.62 to 0.13; I² = 0%).

For the subgroup analysis comparing outcomes for participants with and without calcification, we pooled six‐week to three‐month data from five studies of people with calcific deposits (Gerdesmeyer 2003; Hsu 2008; Kolk 2013; Kvalvaag 2017; Pleiner 2004; 256 participants) and five studies of people without calcific deposits (Galasso 2012; Kolk 2013; Li 2017; Schmitt 2001; Speed 2002; 253 participants). Subgroups did not appear to differ with respect to mean pain (with calcific deposits: SMD –0.59, 95% CI –1.33 to 0.14; 256 participants; without calcific deposits: SMD –0.39, 95% CI –0.70 to –0.09; 253 participants; test for subgroup differences: Chi² = 0.25, df = 1 (P = 0.62), I² = 0% despite the 'without calcification' group achieving statistical significance; Analysis 1.11).

In the sensitivity analyses for pain at six weeks to three months, removing studies at risk of selection bias or detection bias did not alter the findings substantially.

Removal of five studies with possible selection bias (Galasso 2012; Hsu 2008; Kolk 2013; Pleiner 2004; Speed 2002) changed the effect size from SMD –0.66 (95% CI –1.14 to –0.18; I² = 81%; 8 studies, 465 participants) to SMD –0.49 (95% CI –0.76 to –0.21; I² = 0%; 2 studies, 210 participants).

Removal of five studies with possible detection bias (Gerdesmeyer 2003; Hsu 2008; Kolk 2013; Pleiner 2004; Speed 2002) changed the effect size from SMD –0.66 (95% CI –1.14 to –0.18; I² = 81%; 8 studies, 465 participants) to SMD –0.61 (95% CI –0.94 to –0.27; I² = 0%; 3 studies, 142 participants).

Function

Ten trials reported mean function using the Constant score (lower score is worse) (Cosentino 2003; Galasso 2012; Gerdesmeyer 2003; Hearnden 2009; Hsu 2008; Kolk 2013; Kvalvaag 2017; Li 2017; Pleiner 2004; Schmitt 2001), and one trial used the SPADI score (lower score is better) (Speed 2002). We changed the direction of the SPADI scores to 0 to 100 score with a higher score indicating better function.

Seven trials reported function at zero to six weeks (Cosentino 2003; Galasso 2012; Hsu 2008; Li 2017; Pleiner 2004; Schmitt 2001; Speed 2002). There was a statistically significant improvement in function when comparing ESWT to placebo at six weeks' follow‐up (SMD 0.79, 95% CI 0.30 to 1.28; I² = 79%; 374 participants; Analysis 1.3). Using the SD of 12.8 from Gerdesmeyer 2003, this is equivalent to a mean increase of 10.11 points (95% CI 3.84 to 16.38) on a 0‐ to 100‐point scale. The clinical importance of this improvement was uncertain as the 95% CIs included both a clinically important (greater than 10‐point) increase and clinically unimportant (less than 10 points) change.

Nine trials reported function at six weeks to three months (Galasso 2012; Gerdesmeyer 2003; Hsu 2008; Kolk 2013; Kvalvaag 2017; Li 2017; Pleiner 2004; Schmitt 2001; Speed 2002). Based on low‐certainty evidence, there was a statistically significant improvement of uncertain clinical importance in function when comparing ESWT to placebo at three months' follow‐up (SMD 0.62, 95% CI 0.13 to 1.11; I² = 88%; 612 participants; Analysis 1.3). Using the SD of 12.8 from Gerdesmeyer 2003, this translated to a mean increase of 7.93 points (95% CI 1.66 to 14.2) on a 0‐ to 100‐point scale, an absolute improvement of 8% (95% CI 1.6% to 14%), relative improvement of 12% (95% CI 3% to 22%), or NNTB of 3 (95% CI 2 to 18) (summary of findings Table for the main comparison). Removal of the extreme outlier reported in Hsu 2008 reduced heterogeneity to a moderate level (I² = 47%), and removed any clinical significance from the results (SMD 0.26, 95% CI –0.00 to 0.52; I² = 56%), translating to a mean improvement of 3.33 points on a 0‐ to 100‐point scale (95% CI 0.00 to 6.65).

Seven trials reported function at three to six months (Cosentino 2003; Gerdesmeyer 2003; Hearnden 2009; Hsu 2008; Kolk 2013; Kvalvaag 2017; Speed 2002). There was a statistically significant but clinically unimportant improvement in function favouring the ESWT group (SMD 0.91, 95% CI 0.24 to 1.57; I² = 91%; 471 participants; Analysis 1.3). Using the SD of 12.8 from Gerdesmeyer 2003, this translated to a mean increase on the Constant scale of 11.65 points (95% CI 3.07 to 20.1).

Three trials reported function at six to 12 months (Gerdesmeyer 2003; Hsu 2008; Pleiner 2004). There was no evidence of a between‐group difference in function measured using the Constant score (MD 15.18, 95% CI –2.55 to 32.91; I² = 94%; 155 participants). The significant heterogeneity was largely due to Hsu 2008; removal of these more extreme data reduced the heterogeneity to a likely unimportant level, without changing the direction of the effect (MD 6.51, 95% CI –0.07 to 13.10; I² = 20%).

For the subgroup analysis comparing outcomes for participants with and without calcification, we pooled six week to three month data from five trials that included people with calcific deposits (Gerdesmeyer 2003; Hsu 2008; Kolk 2013; Kvalvaag 2017; Pleiner 2004) and five trials including people without calcific deposits (Galasso 2012; Kolk 2013; Li 2017; Schmitt 2001; Speed 2002). Subgroups did not appear to differ with respect to mean function (with calcific deposits: SMD 0.84, 95% CI –0.20 to 1.89; 260 participants; without calcific deposits: SMD 0.29, 95% CI –0.04 to 0.61; 253 participants; test for subgroup differences: Chi² = 1.00, df = 1 (P = 0.32), I² = 0.1%; Analysis 1.12).

In the sensitivity analyses for function at six weeks to three months, removing studies at risk of selection bias or detection bias did not alter the effect size dramatically.

Removal of five studies with possible selection bias (Galasso 2012; Hsu 2008; Kolk 2013; Pleiner 2004; Speed 2002) changed the effect size and eliminated the slight between‐group statistical difference from SMD 0.74 (95% CI 0.18 to 1.31; I² = 88%; 8 studies, 469 participants) to SMD 0.38 (95% CI 0.11 to 0.66; I² = 0%; 3 studies, 210 participants) at six weeks to three months.

Removal of five studies with possible detection bias (Gerdesmeyer 2003; Hsu 2008; Kolk 2013; Pleiner 2004; Speed 2002) changed the effect size and eliminated the slight between‐group statistical difference from SMD 0.74 (95% CI 0.18 to 1.31; I² = 88%; 8 studies, 469 participants) to SMD 0.48 (95% CI –0.02 to 0.97; I² = 45%; 3 studies, 142 participants) at six weeks to three months.

Participant‐reported success

Six trials reported treatment success (Galasso 2012; Gerdesmeyer 2003; Hearnden 2009; Peters 2004; Schmitt 2001; Speed 2002). Low‐certainty evidence indicated there may be no statistical difference in the number reporting success: 255 per 1000 participants reported success with placebo and 405 per 1000 reported success with shock wave therapy (RR 1.59, 95% CI 0.87 to 2.91; I² = 53%; 287 participants; Analysis 1.4), or 15% more (3% fewer to 49% more) participants had success with shock wave therapy, a relative increase of 59% (13% fewer to 191% more) (summary of findings Table for the main comparison).

Quality of life

None of the trials reported quality of life.

Number of participant withdrawals

Withdrawals specifically due to adverse events were not well reported across studies. Three trials reported that there were no withdrawals for any reasons (Galasso 2012; Peters 2004; Schmitt 2001; 167 participants), while only one study explicitly reported a withdrawal due to an adverse event, namely, a single participant withdrew due to intolerance of the shock wave therapy (Speed 2002). Kvalvaag 2017 reported that four participants withdrew from each group with two discontinuing intervention in the shock wave group and three discontinuing intervention in the placebo group due to an adverse event. Cosentino 2003 reported that 23/35 participants dropped out from the placebo group at six months' follow‐up, without reporting the reasons, and also did not explicitly report if any participants dropped out from the shock wave group. Therefore, we could not include data from this study in the analysis.

For withdrawals due to adverse events or treatment intolerance, seven trials provided low‐certainty evidence (Gerdesmeyer 2003;Kolk 2013; Kvalvaag 2017; Li 2017; Peters 2004; Pleiner 2004; Speed 2002). There was no between‐group difference in withdrawals, 103 per 1000 withdrawals in the placebo group compared with 77 per 1000 in the shock wave therapy group (RR 0.75, 95% CI 0.43 to 1.31; I² =0%; 581 participants; Analysis 1.5), an absolute difference of 3% less events (6% less to 3% more), or a relative change of 25% less (57% less to 31% more) (summary of findings Table for the main comparison). One participant in the shock wave group withdrew due to intolerance of the therapy, while other 10 participants who withdrew from active treatment offered no reason. From the placebo group, one participant withdrew due to deteriorating symptoms and a further 12 did not complete treatment but offered no reason for withdrawing.

Number of participants experiencing any adverse event

Several trials reported adverse events incompletely. Cosentino 2003 and Pleiner 2004 explicitly reported that there were zero adverse events in either treatment group, although Cosentino 2003 also reported that there was transient treatment pain associated with shock wave therapy without reporting the number of people who had the event. Hsu 2008 reported transient treatment‐associated pain treated with ice and paracetamol, but did not report the number of participants with the event. Hearnden 2009 reported bruising in 7/11 (62%) participants in the shock wave group, but did not report if participants in the placebo group had any adverse events. Thus treatment‐related pain from these three studies could not be included in the meta‐analysis.

Five trials provided data on the number of participants per treatment group with adverse events for a meta‐analysis (Galasso 2012; Gerdesmeyer 2003; Hsu 2008; Peters 2004; Speed 2002). Low‐certainty evidence indicated no between‐group difference in the proportion of people with adverse events, 72 per 1000 in the placebo group compared with 260 per 1000 in the shock wave therapy group (RR 3.61, 95% CI 2.00 to 6.52; 295 participants; Analysis 1.7), an absolute change of 19% more adverse events with shock wave therapy (7% more to 40% more), or a relative change of 261% more (100% more to 552% more) (summary of findings Table for the main comparison).

The type of adverse events included: pain associated with shock wave therapy or placebo treatment (Cosentino 2003; Galasso 2012; Gerdesmeyer 2003; Hsu 2008; Peters 2004; Speed 2002); localised redness, bleeding or bruising (Gerdesmeyer 2003; Hearnden 2009; Hsu 2008; Peters 2004); and increased shoulder pain following treatment (Peters 2004).

Minor outcomes

Proportion of participants achieving pain score below 30/100 mm on Visual Analogue Scale

None of the trials reported proportion of participants achieving pain score below 30/100 mm on VAS.

Range of movement

None of the trials reported ROM.

Calcification size: number with complete resolution

Four trials reported number of participants with complete resolution of calcium deposits (Cosentino 2003; Hsu 2008; Peters 2004; Pleiner 2004; 218 participants). Peters 2004 (59 participants) reported that no participants in either treatment group had complete resolution of deposits and was not included in the analysis. Based on the other three trials, there was a statistically significant increase in the number of calcium deposits which completely resolved with ESWT compared to placebo although this is of uncertain clinical importance (RR 4.78, 95% CI 1.31 to 17.39; 159 participants; Table 2; Analysis 1.8).

Table 2. Shock wave therapy versus placebo secondary outcomes

Outcome	Number of studies	Number of participants: shock wave	Number of participants: placebo	Statistic random‐effects Mantel‐Haenszel	Effect estimate (95% CI)
Proportion achieving pain score below 30/100 mm on VAS	0	Not reported	Not reported	Not reported	Not reported
Range of movement	0	Not reported	Not reported	Not reported	Not reported
Mean change in calcification width (mm) at 3 months	1	46	42	Mean difference (95% CI)	–26.00 (–85.77 to 33.77)
Proportion with complete calcification resolution	3	91	68	Risk ratio (95% CI)	4.78 (1.31 to 17.39)
Proportion with partial calcification partial resolution	3	91	68	Risk ratio (95% CI)	3.41 (0.95 to 12.23)

CI: confidence interval; VAS: Visual Analogue Scale.

Calcification size: number with partial resolution

Four trials reported the number of participants with partial resolution of calcium deposits (Cosentino 2003; Hsu 2008; Peters 2004; Pleiner 2004: 218 participants). Peters 2004 (59 participants) reported that no participants in either treatment group had partial resolution of deposits and was not included in the analysis. Based upon the other three trials, there was no statistically significant difference in the number of calcium deposits which partially resolved in the ESWT group compared to the placebo group (RR 3.41, 95% CI 0.95 to 12.23; 159 participants; Table 2; Analysis 1.9).

Calcification size: mean or change in mean calcification size

One trial reported mean calcification width at six weeks to three months (Gerdesmeyer 2003). Mean change in size was 56.3 mm in the treatment group compared with 30.3 mm in the placebo group, which was not statistically different (MD –26.00, 95% CI –85.77 to 33.77; 88 participants; Table 2; Analysis 1.10).

One trial reported mean change in calcification size at three to six months (Gerdesmeyer 2003; 46 participants). Mean change was –77.7 mm in the treatment group and –41 mm in the placebo group, which was not statistically different (MD –36.70, 95% CI –94.86 to 21.46; 87 participants; Table 2; Analysis 1.10).

Two trials reported mean calcification width at six to 12 months (Gerdesmeyer 2003; Hsu 2008). Mean change was 5.5 mm in the ESWT group and 9.8 mm in the placebo group, which was not statistically significantly different (MD –21.76, 95% CI –60.99 to 17.46; I² = 86%; 122 participants; Table 2; Analysis 1.10).

Shock wave therapy versus no treatment

One study compared shock wave therapy versus no treatment (Loew 1999).

Major outcomes

Function

There was no between‐group difference in function (Constant score) at three months (mean function: 51.6 in the shock wave group and 47.8 in the no treatment group; MD 3.80, 95% CI –6.33 to 13.93; 40 participants; Analysis 2.1).

Participant‐reported success

At the end of the trial, there was no between‐group difference in the number of participants who reported that the treatment was successful (6/20 participants in the shock wave group versus 1/20 participants in the no treatment group; RR 6.00, 95% CI 0.79 to 45.42; Analysis 2.2).

Other major outcomes

The study did not report participant‐reported pain relief of 30% or greater, mean pain, participant‐reported success, quality of life, number of participant withdrawals and number of participants experiencing any adverse event.

Minor outcomes

Number of participants with complete resolution of calcific deposits

At the end of the trial, there were no between‐group differences in the number of participants who had achieved complete resolution of calcific deposits (4/20 participants in the shock wave group versus 2/20 participants in the no treatment group; RR 2.00, 95% CI 0.41 to 9.71; Analysis 2.3).

Other minor outcomes

The study did not report proportion of participants achieving pain score below 30/100 mm on VAS, ROM or effect of ESWT on the size of the calcification.

Shock wave therapy versus ultrasound‐guided needling with glucocorticoid

One study assessed ESWT versus ultrasound‐guided needling with glucocorticoid (Kim 2014).

Major outcomes

Mean pain

The study incompletely reported mean pain (no measures of variance), therefore, we could not extract or substantiate these data. The authors reported a greater improvement in pain and function with ultrasound‐guided needling than with shock wave therapy.

Function

The study incompletely reported function (no measures of variance), therefore, we could not extract or substantiate these data. The authors reported a greater improvement in pain and function with ultrasound‐guided needling than with shock wave therapy.

Other major outcomes

The study did not report participant reported pain relief of 30% or greater, participant‐reported success, quality of life, number of withdrawals due to adverse events and number of participants experiencing any adverse event.

Minor outcomes

Calcification size: mean calcification width

Mean calcification width decreased in both groups but the difference favoured glucocorticoid needling (mean calcification size was 5.6 mm in the shock wave group versus 0.45 mm in the glucocorticoid needling group; MD 5.15, 95% CI 4.84 to 5.46; 54 participants; Analysis 3.1). This difference is of uncertain clinical importance.

Calcification size: number with complete resolution

Complete resolution of calcific deposits occurred less frequently in the shock wave therapy group (12/29 participants in the shock wave group versus 18/25 participants in the glucocorticoid needling group; RR 0.57, 95% CI 0.35 to 0.95; Analysis 3.2). This difference is of uncertain clinical importance.

Calcification size: number with partial resolution

There was no between‐group difference in the number of participants who had partial resolution of calcific deposits (5/29 participants in the shock wave group versus 3/25 participants in the needling group; RR 1.44, 95% CI 0.38 to 5.42; Analysis 3.3).

Other minor outcomes

The study did not report proportion of participants achieving pain score below 30/100 mm on VAS and ROM.

Radial shock wave therapy versus ultrasound‐guided needling with glucocorticoids

One study assessed RSWT versus ultrasound‐guided needling with glucocorticoids (De Boer 2017).

Major outcomes

Pain

At six weeks to three months, there was a statistically significant and clinically important increase in mean pain (NRS 0 to 10, higher score indicating greater pain) in participants who received RSWT compared to participants who underwent ultrasound‐guided needling with glucocorticoids (MD 1.60, 95% CI 0.13 to 3.07; 25 participants; Analysis 4.1).

At 12 months and greater, there was no statistically significant or clinically important change in mean pain (NRS 0 to 10, higher score indicating greater pain) in participants who received RSWT compared to participants who underwent ultrasound‐guided needling with glucocorticoids (MD 0.20, 95% CI –2.05 to 2.45; 19 participants; Analysis 4.1).

Function

At six weeks to three months, there was no statistically significant or clinically important change in mean function (Constant score 0 to 100, higher score indicating better function or Oxford score, 12 to 60 with a higher score indicating better function) in participants who received RSWT compared to participants who underwent ultrasound‐guided needling with glucocorticoids (Constant score: MD –11.70, 95% CI –24.79 to 1.39; 25 participants; Analysis 4.2; Oxford score: MD –2.30; 95% CI –9.30 to 4.70; 25 participants; Analysis 4.3).

At 12 months and greater, there was no statistically significant or clinically important change in mean function (Oxford score, 12 to 60, higher score indicating better function) in participants who received RSWT compared to participants who underwent ultrasound‐guided needling with glucocorticoids (MD –4.10, 95% CI –15.74 to 7.54; 19 participants; Analysis 4.3).

Participant‐reported success

At the end of the trial, there was no difference in treatment success (proportion of participants with no complaints) in participants who received RSWT compared to participants who underwent ultrasound‐guided needling with glucocorticoids (4/9 participants with RSWT versus 4/10 participants with ultrasound‐guided needling with glucocorticoids; RR 1.11, 95% CI 0.39 to 3.19; Analysis 4.4).

Number of participants experiencing any adverse event

At the end of the trial, there was no difference in the proportion of participants with adverse events in participants who received RSWT compared to participants who underwent ultrasound‐guided needling with glucocorticoids (5/14 participants with RSWT versus 1/11 participants with ultrasound‐guided needling with glucocorticoids; RR 3.93, 95% CI 0.53 to 28.93; Analysis 4.5).

Other major outcomes

The trial did not report participant‐reported pain relief of 30% or greater and quality of life. There were no withdrawals listed due to adverse events.

Minor outcomes

Calcification size

At the end of the trial, there was no difference in the calcification size (number with complete resolution) in participants who received RSWT compared to participants who underwent ultrasound‐guided needling with glucocorticoids (1/14 participants with RSWT versus 5/11 participants with ultrasound‐guided needling with glucocorticoids; RR 0.16, 95% CI 0.02 to 1.16; Analysis 4.6).

Radial shock wave therapy versus supervised exercise

One study assessed rESWT versus supervised exercises (Engebretsen 2009).

Major outcomes

Pain

There was no between‐group differences in mean pain (Likert 0 to 9, 9 indicating severe pain) at any time point (six weeks: 2.9 with shock wave versus 2.6 with supervised exercises; MD 0.30, 95% CI –0.53 to 1.13; 90 participants; six weeks to three months: 2.9 with shock wave versus 2.5 with supervised exercises; MD 0.40, 95% CI –0.36 to 1.16; 102 participants; three to six months: 2.7 with shock wave versus 2.5 with supervised exercises; MD 0.20, 95% CI –0.56 to 0.96; 100 participants; one year: 2.6 with shock wave versus 2.1 with supervised exercises; MD 0.50, 95% CI –0.20 to 1.2; 97 participants; Analysis 5.1).

Function

There was no between‐group differences in mean function (SPADI 0 to 100, 100 indicating worst function) at any time point (six weeks: 33.5 with shock wave versus 25.8 with supervised exercises; MD 7.70, 95% CI –1.57 to 16.97; 90 participants; six weeks to three months: 36.1 with shock wave versus 27.0 with supervised exercises; MD 9.10, 95% CI –1.13 to 19.33; 102 participants; three to six months: 29.2 with shock wave versus 24.5 with supervised exercises; MD 4.70, 95% CI –5.39 to 14.79; 100 participants; 12 months: 27.9 with shock wave versus 24.0 with supervised exercises; MD 3.90, 95% CI –6.08 to 13.88; 97 participants; Analysis 5.2).

Number of participant withdrawals

There was no between‐group difference in withdrawals due to adverse events, but the event rates were too low to be certain (2/52 participants with shock wave versus 1/50 participants with supervised exercise; (RR 3.00, 95% CI 0.32 to 27.91; 104 participants; one study; Analysis 5.3). Withdrawal of one participant from the supervised exercise group was due to increased pain and stiffness consistent with adhesive capsulitis and the two withdrawals from the shock wave group were due to aggravation of pain.

Number of participants experiencing any adverse event

Adverse events included frozen shoulder (two in the exercise group, one in the shock wave group); polymyalgia rheumatica (one in the exercise group); depression (one in the shock wave group); aggravation of pain (two in the shock wave group, crossed over to exercise), and one participant from shock wave group had surgery (unreported if this was due to an adverse event or inefficacy; we have included this as an adverse event). Total adverse events did not differ statistically between groups (5/52 participants with shock wave versus 3/50 participants with supervised exercise (RR 1.60, 95% CI 0.40 to 6.36; Analysis 5.4).

Other major outcomes

The study did not report participant‐reported pain relief of 30% or greater, participant‐reported success and quality of life.

Minor outcomes

Range of movement

There was no between‐group difference in mean active abduction (measured in degrees, data supplied by the trial authors) at any time point (six weeks to three months: 167.65 degrees with shock wave versus 169.6 degrees with supervised exercise group; MD –1.95 degrees, 95% CI –10.50 to 6.60; three to six months: 154.78 degrees with shock wave versus 166.6 degrees with supervised exercise; MD –11.82 degrees, 95% CI –25.37 to 1.73; Analysis 5.5). Data were not reported at one year.

Other minor outcomes

The trial did not report proportion of participants achieving pain score below 30/100 mm on a VAS, size of the calcification and number of participants with complete or partial resolution.

Shock wave therapy plus exercise and advice versus exercise and advice alone

One study assessed ESWT plus a supervised exercise programme (called kinesitherapy) and advice versus kinesitherapy and advice alone (Melegati 2000).

Major outcomes

Function

At six to 12 months, there was a statistically significant but clinically unimportant improvement in function in the shock wave plus exercise and advice group compared to the exercise and advice control group (Constant score: 74.5 with shock wave plus exercise and advice versus 65.15 with exercise and advice control; MD 9.35, 95% CI 4.98 to 13.72; 60 participants; Analysis 13.1).

Other major outcomes

The study did not report participant‐reported pain relief of 30% or greater, mean pain, participant‐reported success of treatment, quality of life, number of participant withdrawals and number of participants experiencing any adverse event.

Minor outcomes

The study did not report proportion of participants achieving pain score below 30/100 mm on VAS, ROM, effect of ESWT on the size of the calcification and number of participants with complete or partial resolution.

Shock wave therapy versus transcutaneous electrical nerve stimulation

One study compared ESWT to TENS (Pan 2003).

Major outcomes

Pain

At six weeks, the MD in pain (measured by 0‐ to 10‐point VAS, higher score indicating more pain) favoured shock wave therapy but the CIs indicated that this may or may not be of clinical importance (pain improvement: 3 points with shock wave therapy versus 1.1 points with TENS; MD –1.90, 95% CI –2.98 to –0.82; 62 participants; Analysis 7.1). At three months, there was a clinically important difference in pain in favour of shock wave therapy (–4.08 points with ESWT versus –1.74 points with TENS; MD –2.34, 95% CI –3.53 to –1.15; 62 participants; Analysis 7.1).

Function

At six weeks, the MD in function (measured by Constant score) favoured shock wave therapy but the CIs indicated that this may or may not be of clinical importance (mean function improvement: 24.12 points with shock wave versus 9.59 points with TENS; MD 14.53, 95% CI 8.70 to 20.36; 62 participants; Analysis 7.2). At three months, there was a clinically important difference in function favouring shock wave therapy (mean function improvement: 28.31 points with shock wave versus 11.86 points with TENS; MD 16.45, 95% CI 9.86 to 23.04; 62 participants; Analysis 7.2).

Number of participant withdrawals

There was only one withdrawal due to severe pain from the TENS group. It was not clearly reported if the pain was due to the TENS treatment (or due to the shoulder disorder). The difference between groups was not statistically significant, but there were too few events to be conclusive (0/33 participants with shock wave versus 1/29 participants with TENS; RR 0.29, 95% CI 0.01 to 6.95; Analysis 7.3).

Number of participants experiencing any adverse event

Reported adverse events included soreness due to the shock wave therapy (five participants) or pain, possibly due to TENS (one participant), anxiety resulting in heart palpitations in the shock wave group (one participant). No haematomas or paraesthesia were reported. There were no statistical differences between the number of participants who experienced an adverse event, but there were too few events to be certain (6/33 participants with shock wave versus 1/29 with TENS; RR 5.27, 95% CI 0.67 to 41.00; Analysis 7.4).

Other major outcomes

The study did not report participant‐reported pain relief of 30% or greater, participant‐reported success and quality of life were not reported.

Minor outcomes

Calcification size: mean calcification width

At six weeks, there was a greater reduction in mean width of calcific deposits in the shock wave therapy group (mean change: –3.16 mm with shock wave versus –0.75 mm with TENS; MD –2.41, 95% CI –3.94 to –0.88; 62 participants; Analysis 7.5). This is of unknown clinical relevance.

At six weeks to three months, there was a greater reduction in mean width of calcific deposits in the shock wave therapy group (mean change: –4.39 mm with shock wave versus –1.65 mm with TENS; MD –2.74, 95% CI –4.39 to –1.09; 62 participants; Analysis 7.5). This is of unknown clinical relevance.

Other minor outcomes

The study did not report proportion of participants achieving pain score below 30/100 mm on VAS, ROM and complete or partial resolution of calcification.

Comparisons of different parameters of shock wave therapy

High‐dose versus low‐dose shock wave therapy

Eleven studies compared high‐dose to low‐dose shock wave therapy (Albert 2007; Cacchio 2006; Farr 2011; Gerdesmeyer 2003; Ioppolo 2012; Loew 1999; Perlick 2003; Peters 2004; Rompe 1998; Sabeti 2007; Schofer 2009).

Major outcomes

Participant reported pain relief of 30% or greater

None of the trials reported participant reported pain relief of 30% of greater.

Pain

Two trials reported pain at six weeks (Cacchio 2006; Farr 2011). There was a slight improvement in pain that favoured high‐dose shock wave therapy (mean pain on a 0‐ to 10‐point VAS, 10 indicating most pain: 2 points with high‐dose versus 5 points with low‐dose; SMD ‐1.73, 95% CI ‐3.94 to 0.48; 117 participants; I² = 95%; Analysis 8.1). Although the 95% CIs included both a clinically important and a clinically unimportant pain reduction (assuming a clinically important difference is 1.5 points), the clinical significance of this improvement may be unimportant. The high heterogeneity was largely driven by Cacchio 2006, who reported a large improvement with high‐dose therapy.

Six trials reported pain at three months (Albert 2007; Farr 2011; Gerdesmeyer 2003; Ioppolo 2012; Sabeti 2007; Schofer 2009). There was no statistical between‐group difference in pain (SMD –0.26, 95% CI –0.67 to 0.16; I² = 70%; 326 participants; Analysis 8.1). Based on an SD of 1.9 (Gerdesmeyer 2003), this translates to a mean reduction in pain of 0.49 points (95% CI –1.27 to 0.31) on a 0‐ to 10‐point scale.

Four trials reported pain at three to six months (Cacchio 2006; Gerdesmeyer 2003; Ioppolo 2012; Perlick 2003). There was a slight, possibly clinically unimportant, improvement in pain favouring the high‐dose group (SMD –1.66, 95% CI –2.98 to –0.33; I² = 96%; 326 participants; Analysis 8.1). Based on an SD of 1.9 (Gerdesmeyer 2003), this translates to a mean reduction of 3.15 points (95% CI –5.66 to –0.63) on a 0‐ to 10‐point scale, the 95% CIs include both a clinically important and a clinically unimportant pain reduction. The heterogeneity was driven by the more extreme improvements reported in Cacchio 2006 and Ioppolo 2012; removing their data reduced heterogeneity to zero (SMD –0.47, 95% CI –0.77 to –0.17).

Three trials reported pain at six to 12 months (Gerdesmeyer 2003; Perlick 2003; Schofer 2009). There was no between‐group difference in pain (SMD –0.60, 95% CI –1.39 to 0.18, I² = 85%; 196 participants; Analysis 8.1). Based on a SD of 1.9 (Gerdesmeyer 2003), this translated to a mean reduction of 1.14 points (95% CI –2.64 to 0.34) on a 0‐ to 10‐point scale.

Function

Two trials reported function at six weeks (Cacchio 2006; Farr 2011). While there were no between‐group differences (SMD 3.71, 95% CI –3.71 to 11.14; I² = 99%; 117 participants; Analysis 8.2), the heterogeneity meant the pooled effect size was uninterpretable. Cacchio 2006 found a large benefit favouring high‐dose therapy while Farr 2011 found no between‐group difference.

Seven trials reported function at three months (Albert 2007; Farr 2011; Gerdesmeyer 2003; Ioppolo 2012; Loew 1999; Sabeti 2007; Schofer 2009). There was a clinically unimportant benefit favouring high‐dose therapy (SMD 0.31, 95% CI 0.08 to 0.53; I² = 11%; 366 participants; Analysis 8.2). Based on an SD of 12.8 (Gerdesmeyer 2003), this translated to a mean increase of 4.0 points (95% CI 1.02 to 6.78) on a 0‐ to 100‐point scale. Assuming an minimal clinically important difference of 10 points, this benefit was not clinically significant.

Five trials reported function at six months (Cacchio 2006; Gerdesmeyer 2003; Ioppolo 2012; Perlick 2003; Rompe 1998). The analysis favoured the high‐dose ESWT group, although there was significant heterogeneity (SMD 2.29, 95% CI 1.05 to 3.52; I² = 96%; 409 participants; Analysis 8.2). Based on an SD of 12.8 (Gerdesmeyer 2003), this translated to a mean increase of 29.31 points (95% CI 13.44 to 45.06) on a 0‐ to 100‐point Constant scale. Heterogeneity was reduced but still substantial with removal of the more outlying study (I² = 79%; Cacchio 2006) (SMD 1.36, 95% CI 0.81 to 1.91; equivalent to a mean increase of 17.4 points, 95% CI 10.4 to 24.4, on a 0‐ to 100‐point function scale).

Three trials reported function at 12 months using the Constant score (Gerdesmeyer 2003; Perlick 2003; Schofer 2009). The MD favoured the high‐dose group but the CIs indicated that this may or may not be of clinical importance (MD 12.47, 95% CI 6.91 to 18.03; I² = 0%; 196 participants); Analysis 8.2).

Participant‐reported success

Six trials reported participant‐reported success at the end of the trial (Albert 2007; Cacchio 2006; Gerdesmeyer 2003; Loew 1999; Peters 2004; Rompe 1998). There was a clinically important increase in the proportion of successful treatments in the high‐dose compared with the low‐dose ESWT group (174/221 participants with high dose versus 61/229 participants with low dose; RR 2.74, 95% CI 1.58 to 4.77; I² = 80%; 450 participants; Analysis 8.3). However, the large effect and the high heterogeneity was driven largely by Cacchio 2006 who reported no success with low‐dose therapy, and Peters 2004 who reported that 31/31 (100%) participants had success in the high‐dose group compared to only 4/30 (13%) in the low‐dose group. Removal of these two studies with outlying results modified the effect size to a more moderate increase in success rate and eliminated statistical heterogeneity (RR 1.96, 95% CI 1.57 to 2.45; I² = 0%).

Number of participant withdrawals

Cacchio 2006 reported that no participants withdrew from the study due to adverse events. No other studies reported if there were any withdrawals.

Number of participants experiencing any adverse event

Five trials reported adverse events (Albert 2007; Cacchio 2006; Perlick 2003; Peters 2004; Schofer 2009). A sixth trial reported that haematomas occurred in participants in the high‐dose group, without reporting the number of participants who had the event, so data from this study could not be included in the analysis (Loew 1999). More participants reported adverse events in the high‐dose shock wave group (89/175 participants with high dose versus 23/173 participants with low dose; (RR 3.51, 95% CI 1.53 to 8.03; I² = 17%; 351 participants; Analysis 8.5).

Adverse events included bruising or skin lesions with high‐dose treatment (Albert 2007; Cacchio 2006; Loew 1999; Perlick 2003; Peters 2004); increased shoulder pain following treatment (Perlick 2003; Peters 2004; Schofer 2009); and acute subacromial bursitis possibly associated with shock wave penetration (Perlick 2003).

One participant in the low‐dose group of one trial reported a panic attack (Albert 2007).

Minor outcomes

Proportion of participants achieving pain score below 30/100 mm on Visual Analogue Scale

None of the trials reported the proportion of participants achieving pain score below 30/100 mm on VAS.

Range of movement

One trial reported ROM (Cacchio 2006).

At six weeks, active flexion was much greater in the high‐dose shock wave group (134 degrees with high dose versus 85.00 degrees with low dose; MD 49.35, 95% CI 37.39 to 61.31; 90 participants; Analysis 8.6).

At six months, active flexion favoured the high‐dose group (152.00 degrees with high dose versus 90 degrees with low dose; MD 62.00, 95% CI 50.59 to 73.41; 90 participants; Analysis 8.6).

Calcification size: number with complete resolution

Five trials reported the number of participants with complete resolution of calcium deposits at the end of the trial (Loew 1999; Perlick 2003; Peters 2004; Pleiner 2004; Rompe 1998). More participants in the high‐dose shock wave therapy group had complete resolution (73/172 (42%) participants with high dose versus 20/166 (12%) participants with low dose; (RR 2.91, 95% CI 1.04 to 8.15; I² = 72%; 281 participants; Analysis 8.7).

Calcification size: number with partial resolution

Two trials reported number of participants with partial resolution of calcium deposits at the end of the trial (Perlick 2003; Rompe 1998). There was no between‐group differences in partial resolution (29/90 participants with high dose versus 26/90 participants with low dose; RR 1.13, 95% CI 0.73 to 1.75; I² = 0%; Analysis 8.8).

Calcification size: mean calcification width

Three trials reported mean change in calcification size at six months (Cacchio 2006; Gerdesmeyer 2003; Ioppolo 2012). There was a greater reduction in the high‐dose therapy group (MD –24.19, 95% CI –44.83 to –3.55; I² = 31%; 229 participants; Analysis 8.9).

One trial reported mean change in calcification size at 12 months (Gerdesmeyer 2003). There was a greater reduction in the high‐dose group (MD –70.70, 95% CI –141.05 to –0.35; 79 participants; Analysis 8.9).

Calcification size: greater than 80% reduction of calcified surface on anteroposterior view

One trial reported proportion of participants with greater than 80% reduction of calcified surface on anteroposterior view at the end of the trial (Albert 2007). There was no evidence of a difference (6/40 participants with high dose versus 2/40 participants with low dose; RR 3.00, 95% CI 0.64 to 13.98; 80 participants; Analysis 8.10).

Two versus one treatment session of shock wave therapy

One small trial (40 participants) compared one versus two treatment sessions of ESWT (Loew 1999), and reported only function, treatment success and adverse events. Findings were uncertain given that the evidence was very‐low certainty due to the small number of participants and potential for selection, performance, detection and selective reporting bias.

Major outcomes

Function

There was no evidence of a difference in function at three months (mean function using Constant score 0 to 100, 0 indicating worst function: 68.5 (SD 13.1) with two sessions versus 63.7 (SD 14.6) with one session (MD 4.80, 95% CI ‐3.80 to 13.40; one study, 40 participants; Analysis 9.1).

Participant‐reported success

There was no evidence of a difference in treatment success (proportion of participants satisfied with the treatment) (14/20 participants with two sessions versus 12/20 participants with one session (RR 1.17, 95% CI 0.74 to 1.85; one study, 40 participants; Analysis 9.2).

Number of participants experiencing any adverse event

Loew 1999 reported that haematomas occurred in participants in the two‐session group, without reporting the number of participants who had the event, so these data could not be included in an analysis.

Other major outcomes

The study did not report participant‐reported pain relief of 30% or greater, pain, quality of life, withdrawals due to adverse events and the number of people with adverse events.

Minor outcomes

Proportion with resolution of calcification

There was no evidence of a difference in the number of participants with resolution of calcifications (12/20 participants with two sessions versus 11/20 participants with one session (RR 1.09, 95% CI 0.64 to 1.86; 40 participants one study; Analysis 9.3).

Other minor outcomes

The study did not report proportion of participants achieving pain score below 30/100 mm on VAS, ROM and size of the calcification.

Shock wave therapy directed to the calcific deposits or to the supraspinatus origin

One study compared calcification‐focused ESWT with supraspinatus origin‐focused ESWT (Haake 2002).

Major outcomes

Participant reported pain relief of 30% or greater

The trial did not report participant‐reported pain relief of 30% or greater.

Pain

There was no statistically significant difference in pain when comparing calcification‐focused ESWT with supraspinatus origin‐focused ESWT at three months' follow‐up (mean pain at rest, visual NRS 0 to 11, 11 indicating worst pain: 3.21 with calcification‐focused ESWT versus 4.74 with supraspinatus origin‐focused ESWT; MD –1.53, 95% CI –3.24 to 0.18; 47 participants; Analysis 10.1).

There was a statistically significant but clinically unimportant decrease in pain when comparing calcification‐focused ESWT with supraspinatus origin‐focused ESWT at 12 months' follow‐up (mean pain at rest, visual NRS 0 to 11, 11 indicating worst pain: 1.48 with calcification‐focused ESWT versus 3.75 with supraspinatus origin‐focused ESWT; MD –2.27, 95% CI –3.49 to –1.05; 49 participants; Analysis 10.1).

Function

There was a statistically significant and clinically important increase in function when comparing calcification‐focused ESWT with supraspinatus origin‐focused ESWT at six weeks to three months' follow‐up (mean function using Constant score 0 to 100, 1000 indicating best function: 104.59 with calcification‐focused ESWT versus 73.08 with supraspinatus origin‐focused ESWT; MD 31.51, 95% CI 16.33 to 46.69; 47 participants; Analysis 10.2).

There was a statistically significant and clinically important increase in function when comparing calcification‐focused ESWT with supraspinatus origin‐focused ESWT at 12 months' follow‐up (mean function using Constant score 0 to 100, 100 indicating best function: 116.24 with calcification‐focused ESWT versus 83.51 with supraspinatus origin‐focused ESWT; MD 32.73, 95% CI 20.40 to 45.06; 49 participants; Analysis 10.2).

Participant‐reported success

Haake 2002 measured treatment success by the proportion of participants satisfied with the treatment. There was a statistically significant but clinically unimportant increase in success rate in the calcification‐focused ESWT group compared with the supraspinatus origin‐focused ESWT group (25/25 participants with calcification‐focused ESWT versus 10/24 participants with supraspinatus origin‐focused ESWT; RR 2.34, 95% CI 1.47 to 3.71; Analysis 10.3).

Quality of life

The trial did not report quality of life.

Number of participant withdrawals

The trial did not report number of participant withdrawals.

Number of participants experiencing any adverse event

Haake 2002 reported that no participants experienced adverse events during the study. These data could not be analysed in this review.

Minor outcomes

Calcification size: number with complete resolution

There was a statistically significant increase of uncertain clinical significance in the number with complete resolution in the calcification‐focused ESWT group compared with supraspinatus origin‐focused ESWT group at the end of the trial (14/24 participants with calcification‐focused ESWT group versus 8/22 participants with supraspinatus origin‐focused ESWT (RR 1.60, 95% CI 0.84 to 3.07; 46 participants; one study; Analysis 10.4).

Other minor outcomes

The trial did not report proportion of participants achieving pain score below 30/100 mm on VAS, ROM and calcification width.

Palpation‐guided versus image‐guided shock wave therapy

One study compared palpation‐guided ESWT to image‐guided ESWT (Sabeti‐Aschraf 2005).

Major outcomes

Pain

There was a statistically significant and clinically important difference in improvement in pain favouring the image‐guided ESWT at three months (mean pain using a 0‐ to 100‐point VAS, 100 indicating most pain: 18.21 with image‐guided ESWT versus 33.36 with palpation‐guided ESWT; MD –15.15, 95% CI –26.62 to –3.68; 50 participants; Analysis 11.1).

Function

There was no between‐group difference in function at three months (mean Constant score: 79.48 with image‐guided ESWT versus 73.00 with palpation‐guided ESWT; MD 6.48, 95% CI –2.22 to 15.18; 50 participants; Analysis 11.2).

Number of participants experiencing any adverse event

There were no adverse events reported.

Other major outcomes

The trial did not report participant‐reported pain relief of 30% or greater, participant‐reported success, quality of life and withdrawals due to adverse events.

Minor outcomes

Calcific deposits: number with complete resolution

There was no difference in the number of participants who had complete resolution of calcific deposits at the end of the trial (6/25 participants with image‐guided ESWT versus 1/25 participants with palpation‐guided ESWT; RR 6.00, 95% CI 0.78 to 46.29; Analysis 11.3).

Calcification size: number with partial resolution

There was no difference in the number of participants who had partial resolution of calcific deposits at the end of the trial (7/25 participants with image‐guided ESWT versus 5/25 participants with palpation‐guided ESWT; RR 1.40, 95% CI 0.51 to 3.82; Analysis 11.4).

Other minor outcomes

The trial did not report proportion of participants achieving pain score below 30/100 mm on VAS, ROM and mean calcification width.

ESWT with hyperextended arm position versus ESWT with neutral arm position

One trial compared ESWT treatment given in a neutral arm position compared with a hyperextended arm position (Tornese 2011).

Major outcomes

Pain

There was no statistically significant difference in pain when comparing hyperextended arm position ESWT with neutral arm position ESWT at 3 months' follow‐up (mean pain using 0‐ to 15‐point VAS, 15 indicating worst pain: 10.9 with hyperextended arm position ESWT versus 9.2 with neutral arm position ESWT; MD 1.70, 95% CI –0.55 to 3.95; 35 participants; Analysis 12.1).

Function

There was a statistically significant but clinically unimportant increase in function when comparing hyperextended arm position ESWT with neutral arm position ESWT at three months' follow‐up (mean function using Constant score 0 to 100, 100 indicating best function: 76.9 with hyperextended arm position ESWT versus 67.9 with neutral arm position ESWT; MD 9.00, 95% CI 0.72 to 17.28; 35 participants; Analysis 12.2).

Other major outcomes

The study did not report participant‐reported pain relief of 30% or greater, treatment success, quality of life, withdrawals due to adverse events and number of participants experiencing any adverse event.

Minor outcomes

Calcification size: greater than 80% reduction of calcified surface on anteroposterior view

There was no difference in number of participants who achieved greater than 80% reduction of calcified surface on anteroposterior view at the end of the trial (12/18 participants with hyperextended arm position ESWT versus 6/17 with neutral arm position ESWT; RR 1.89, 95% CI 0.92 to 3.89; Analysis 12.3).

Other minor outcomes

The study did not report proportion of participants achieving pain score below 30/100 mm on VAS, ROM and mean calcific deposit width.

ESWT versus ultrasound‐guided percutaneous lavage

One study investigated ESWT versus ultrasound‐guided percutaneous lavage (Del Castillo‐Gonzales 2016).

Major outcomes

Pain

There was no evidence of a difference in mean pain (0‐ to 10‐point VAS, 10 indicating worst pain) when comparing ESWT to ultrasound‐guided percutaneous lavage at zero to six weeks (MD –0.10, 95% CI –0.26 to 0.06; 201 participants; Analysis 6.1).

There was a statistically and clinically significant increase in mean pain (0‐ to 10‐point VAS, 10 indicating worst pain) when comparing ESWT to ultrasound‐guided percutaneous lavage at six weeks to three months (MD 1.90, 95% CI 1.54 to 2.26; 201 participants; Analysis 6.1).

There was a statistically significant increase in mean pain of uncertain clinical significance (0‐ to 10‐point VAS, 10 indicating worst pain) when comparing ESWT to ultrasound‐guided percutaneous lavage at three to six months (MD 1.80, 95% CI 1.36 to 2.24; 201 participants; Analysis 6.1).

There was a statistically significant increase in mean pain of uncertain clinical significance (0‐ to 10‐point VAS, 10 indicating worst pain) when comparing ESWT to ultrasound‐guided percutaneous lavage (MD 1.90, 95% CI 1.34 to 2.46; 201 participants; Analysis 6.1).

Participant‐reported success

There was no statistically significant difference in treatment success (proportion of participants who were pain‐free) when comparing ESWT to ultrasound‐guided percutaneous lavage at the end of the trial (RR 0.91, 95% CI 0.81 to 1.03; 201 participants; Analysis 6.2).

Number of participants experiencing any adverse event

There was a statistically significant increase in the risk of experiencing an adverse event when comparing ESWT to ultrasound‐guided percutaneous lavage at the end of the trial (RR 0.08, 95% CI 0.00 to 1.36; 243 participants; Analysis 6.3).

Minor outcomes

Calcification size

There was a statistically significant decrease in calcification size when comparing ESWT to ultrasound‐guided percutaneous lavage at zero to six weeks (MD –2.00 mm, 95% CI –2.94 to –1.06; 201 participants; Analysis 6.4).

There was a statistically significant increase in calcification size when comparing ESWT to ultrasound‐guided percutaneous lavage at six weeks to three months (MD 2.00 mm, 95% CI 1.17 to 2.83; 201 participants; Analysis 6.4).

There was a statistically significant increase in calcification size when comparing ESWT to ultrasound‐guided percutaneous lavage at three to six months (MD 2.40 mm, 95% CI 1.44 to 3.36; 201 participants; Analysis 6.4).

There was a statistically significant increase in calcification size when comparing ESWT to ultrasound‐guided percutaneous lavage at six to twelve months (MD 3.10 mm, 95% CI 2.07 to 4.13; 201 participants; Analysis 6.4).

Calcification size (complete resolution)

There was a statistically significant increase in the chance of complete resolution of calcification when comparing ESWT to ultrasound‐guided percutaneous lavage at the end of the trial (RR 0.65, 95% CI 0.53 to 0.80; 201 participants; Analysis 6.5).

ESWT versus ultrasound‐guided hyaluronic acid injection

One study compared shock wave therapy to ultrasound‐guided hyaluronic acid injection (Frizziero 2017).

Major outcomes

Pain

The study measured pain on the DASH scale postintervention and at three months' follow‐up. We did not use these data in our review.

Function

There was evidence of a difference in function when comparing the ESWT group with the ultrasound‐guided hyaluronic acid injection group at three months' follow‐up (mean function using Constant score 0 to 100, 100 indicating best function: 76.5 (SD 20.6) with ESWT versus 81.8 with ultrasound‐guided hyaluronic acid injection; SMD –0.26, 95% CI –0.94 to 0.41; 34 participants; Analysis 14.1).

Other major outcomes

The study did not report participant‐reported pain relief of 30% or greater, participant‐reported success, quality of life, proportion of participants with adverse events and withdrawals.

Minor outcomes

The study did not report proportion of participants achieving pain score below 30/100 mm on VAS, ROM, size of the calcification and number of participants with complete or partial resolution.

rESWT plus physiotherapy versus physiotherapy

One study compared rESWT plus physiotherapy with physiotherapy alone (Duymaz 2019).

Major outcomes

Pain

There was a statistically significant but clinically unimportant improvement in pain in the rESWT plus physiotherapy group compared to the physiotherapy group alone postintervention (mean pain measured on 0‐ to 10‐point VAS, 10 indicating most pain: 1.3 with rESWT plus physiotherapy versus 2.5 with physiotherapy alone; MD –1.20, 95% CI –1.58 to –0.82; 80 participants; Analysis 15.1).

Function

There was a statistically significant and clinically important improvement in function in the rESWT plus physiotherapy group compared to the physiotherapy group alone (mean function measured on quickDASH scale of 0 to 100, 100 indicating most disability: 1.3 with rESWT plus physiotherapy versus 12.6 with physiotherapy alone; MD –11.30, 95% CI –14.75 to –7.85; 80 participants; Analysis 15.2).

Other major outcomes

The study did not report participant‐reported pain relief of 30% or greater, quality of life, number of participant withdrawals and number of participants experiencing any adverse event.

Minor outcomes

Range of movement

There was a statistically significant improvement in flexion with rESWT plus physiotherapy compared to physiotherapy alone postintervention (measured using a goniometer: 171.1 with rESWT plus physiotherapy versus 139.5 with physiotherapy alone; MD 31.60, 95% CI 24.04 to 39.16; 80 participants; Analysis 15.3). There was a statistically significant improvement in extension with rESWT plus physiotherapy group compared to physiotherapy alone postintervention (measured using a goniometer: 33.8 with rESWT plus physiotherapy versus 16.8 with physiotherapy alone; MD 17.00, 95% CI 14.10 to 19.90; 80 participants; Analysis 15.4). There was a statistically significant improvement in abduction with rESWT plus physiotherapy group compared to physiotherapy alone postintervention (measured using a goniometer: 167 with rESWT plus physiotherapy versus 125.2 with physiotherapy alone; MD 41.80, 95% CI 32.79 to 50.81; 80 participants; Analysis 15.5). There was a statistically significant improvement in external rotation with rESWT plus physiotherapy compared to physiotherapy alone postintervention (measured using a goniometer: 49 with rESWT plus physiotherapy versus 25.8 with physiotherapy alone; MD 23.20, 95% CI 16.98 to 29.42; 80 participants; Analysis 15.6).

Other minor outcomes

The study did not report proportion of participants achieving pain score below 30/100 mm on VAS, size of the calcification and number of participants with complete or partial resolution.

Discussion

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Summary of main results

Compared to placebo, there was moderate‐certainty evidence that shockwave therapy provides no clinically important improvement in pain and function at three months following treatment, and low‐certainty evidence indicating there may also be no improvement in the number of participants with a pain reduction of 50% or more and the number with participant‐reported treatment success. It is uncertain if therapy increases withdrawal rate and adverse events, due to the small number of events (summary of findings Table for the main comparison). None of the studies measured quality of life. There were also no clinically important differences between shock wave therapy and placebo at any other time points.

Subgroup analyses indicated that pain and function outcomes did not differ between those participants who did or did not have calcific deposits.

Shock wave therapy was associated with an increased rate of complete resolution of calcium deposits by the end of the trial, but this was of uncertain clinical significance. The studies did not measure the proportion of participants achieving a pain score below 30/100 mm on VAS, ROM and number of participants with partial resolution of calcific deposits.

Evidence was downgraded due to the risk of selection, detection or reporting bias, or a combination of these biases, as well as imprecision or heterogeneity.

We are uncertain if shock wave therapy has any benefits over ultrasound‐guided needling, TENS, supervised exercises, no treatment, percutaneous lavage or multiple versus single treatments, as there was only low‐ to very low‐certainty evidence from single or few small studies.

There was very low‐certainty evidence that high‐dose shockwave therapy may provide a clinically important benefit compared with low‐dose shock wave therapy at the end of the trial with respect to treatment success and function. Higher doses also had a benefit of uncertain clinical significance with respect to ROM and reduction of calcific deposits. High‐dose therapy had a higher risk of adverse events but not withdrawals. There were no clinically important differences between high‐dose and low‐dose shock wave therapy at any other time points. Evidence was downgraded due to the risk of multiple biases, imprecision, heterogeneity and indirectness for pain and function.

Adverse events of shock wave therapy reported in the trials included treatment‐related pain, bruising and bleeding, although these were self‐limiting.

Rare and potential serious adverse events, such as osteonecrosis of the bone of the upper arm (loss of blood supply and bone death) while theoretically possible, were not reported in the studies.

Overall completeness and applicability of evidence

There was inconsistent reporting of major outcomes across trials (Table 3). Overall pain and function were reported commonly (96% of trials for both), but were often not reported fully, for example without measures of variance, or in some studies only reported in the treatment group, precluding their inclusion in the analyses. A lower proportion of trials measured the other major outcomes. No trial reported participant‐reported pain relief of 30% or greater, although one trial reported pain relief of 50% or greater, which we reported. Fifty percent of trials reported treatment success, no trial included quality of life, 25% reported withdrawals and 64% reported withdrawals due to adverse events.

Table 3. Outcome Reporting Bias In Trials (ORBIT) matrix

Study ID	Major outcomes
Study ID	Participant‐reported pain relief ≥ 50%	Pain	Function or disability	Treatment success	Quality of life	Withdrawal due to adverse events	Adverse events
Albert 2007	?	Full	Full	Full	?	?	Full
Cacchio 2006	?	Full	Full	Full	?	Full	Full
Cosentino 2003	?	Partial	Full	?	?	?	Full
De Boer 2017	?	Full	Full	Full	?	?	Full
Del Castillo‐Gonzales 2016	?	Full	?	Full	?	?	Full
Duymaz 2019	?	Full	Full	?	?	?	?
Engebretsen 2009	?	Full	Full	?	?	Full	Full
Farr 2011	?	Full	Full	?	?	?	Full
Frizziero 2017	?	Partial	Full	?	?	?	?
Galasso 2012	?	Full	Full	Full	?	Full	Full
Gerdesmeyer 2003	?	Full	Full	Full	?	?	Full
Haake 2002	?	Full	Full	Full	?	?	Full
Hearnden 2009	?	Partial	Partial	Full	?	?	Partial
Hsu 2008	?	Full	Full	Full	?	?	Full
Ioppolo 2012	?	Full	Full	?	?	?	?
Kim 2014	?	Partial	Partial	?	?	?	?
Kolk 2013	?	Full	Full	?	?	?	?
Kvalvaag 2017	?	Full	Full	?	?	Full	Partial
Li 2017	?	Full	Full	?	?	?	Full
Loew 1999	?	Not measured	Full	Full	?	?	?
Melegati 2000	?	Not measured	Full	?	?	?	?
Pan 2003	?	Full	Full	?	?	Full	Full
Perlick 2003	?	Full	Partial	?	?	?	Full
Peters 2004	?	?	?	Full	?	Full	Full
Pleiner 2004	?	Full	Measured	?	?	?	?
Rompe 1998	?	Not measured	Partial	Full	?	?	?
Sabeti 2007	?	Full	Full	Full	?	?	?
Sabeti‐Aschraf 2005	?	Full	Full	?	?	?	Full
Schmitt 2001	?	Full	Full	Full	?	Full	Full
Schofer 2009	?	Full	Full	?	?	?	Full
Speed 2002	Full	Partial	Full	Full	?	Full	Full
Tornese 2011	?	Full	Full	?	?	?	?

'Full': sufficient data for inclusion in a meta‐analysis was reported (e.g. mean, standard deviation and sample size per group for continuous outcomes).
'Partial': insufficient data for inclusion in a meta‐analysis was reported (e.g. means only, with no measures of variance).
'Measured': outcome was measured but no outcome data was reported.
'Not measured': outcome was not measured by the trialists.
'?': unclear whether the outcome was measured or not (as a trial protocol was unavailable).

Inclusion of a core outcome measures in future trials would facilitate the ability to synthesise the evidence, compare results between trials and increase the certainty of our conclusions (Buchbinder 2017; Page 2015; Page 2016c; Page 2018).

Additionally, there was no standard approach to shock wave therapy in terms of type of shock wave, dose and frequency of treatment, and the placebo controls varied across trials. This resulted in marked clinical heterogeneity across studies leading to uncertainty in interpreting the pooled analyses.

While we did find that shock wave therapy, particularly in high doses, resulted in a greater number of people with complete resolution of calcific deposits when present, this did not appear to translate into improved patient‐relevant outcomes of pain, function or treatment success.

Two RCTs that were potentially eligible for inclusion in this review did not have available results. However, we believe it is unlikely that inclusion of these studies in our review would change our conclusions.

Quality of the evidence

We used the GRADE approach to assess the certainty of the evidence (Schünemann 2011a). Moderate‐certainty evidence suggests that compared to placebo, shock wave therapy results in a small but clinically uncertain improvement in mean pain and function. It did not appear to matter if participants had calcific deposits or not. Evidence was downgraded due to the potential for selection, performance, detection and reporting biases, There was also considerable heterogeneity, but, as it was largely driven by a pseudo‐randomised trial with outlier results, we did not downgrade the evidence further.

Shock wave therapy may not have an effect on participant‐reported pain relief of 50% or greater and treatment success, but as this is based on low‐certainty evidence, we could not be certain. Evidence was downgraded due potential bias arising from inadequate study design and imprecision: only a single poorly designed study reported pain relief of 50% or more, and although 287 participants from six poorly reported studies reported treatment success, CIs around the effect estimate were wide, due to the small number of events in most studies. Low‐certainty evidence was also available from seven studies for withdrawals and five studies for adverse events. Evidence was downgraded due to potential for bias and imprecision. We are uncertain if withdrawals or adverse events differed between groups due to the small number of events. Shock wave therapy did result in more people with complete resolution of calcium deposits compared to placebo. Quality of life was not measured.

We are uncertain if shock wave therapy has any benefits over ultrasound‐guided glucocorticoid needling, TENS, exercise or no treatment, or different regimens of shock wave therapy as there was only low‐certainty evidence from single or few small studies, subject to bias and imprecision.

We are uncertain if higher doses of shock wave therapy has any benefit and more adverse events over lower doses, due to very low‐certainty evidence. Evidence was downgraded due to imprecision, bias, heterogeneity and indirectness due to variability and lack of consensus in recommended treatment dose.

Potential biases in the review process

We performed a thorough search of CENTRAL, MEDLINE, Embase, ClinicalTrials.gov and WHO International Clinical Trials Registry Platform databases using a sensitive search strategy without restricting by date or language to identify published and unpublished studies, so it is unlikely that we missed any relevant studies. We could not fully assess publication bias because we did not have enough trials. However, unpublished trials may be more likely to show no benefit of shock wave therapy and are, therefore, unlikely to change our conclusions.

We identified five ongoing studies, one comparing needle aspiration of calcific deposits versus ESWT (NTR7093), one comparing rESWT to ultrasound‐guided needle puncture or to a combination of both interventions (NCT02677103), one comparing focussed ESWT to rESWT (ChiCTR1900022932), another comparing high energy ESWT to low energy ESWT to sham (NCT03779919), and one comparing ESWT to steroid injection (PACTR201910650013453). As these studies have varied comparators and would be presented as single studies in stand‐alone comparisons, it appears that inclusion of the results when available are unlikely to impact on the conclusions of this review.

Two review authors independently assessed the trials for inclusion, extracted data and assessed the risk of bias, and a third review author adjudicated when any discrepancy arose. Review questions of interest were defined with full knowledge of the possible comparisons that could be undertaken, but no knowledge of the results of any comparisons. To prevent selective inclusion of results we used predefined decision rules to select data from trials when multiple measurement scales, time points and analyses were reported.

A limitation of the review was that many trials did not report major outcomes or presented outcome data incompletely and attempts to obtain unpublished data from trialists were largely unsuccessful.

We identified nine studies published in languages other than English that we could not translate at the time of submission of the review, and thus these studies are still awaiting classification. We do not consider that the results of these studies are likely to alter the conclusions of the review substantially.

Agreements and disagreements with other studies or reviews

Two other systematic reviews comparing shock wave therapy to placebo have been published (Bannuru 2014; Ioppolo 2013). However, Bannuru 2014 did not identify the time points at which it was extracting data and stratified its included trials based on higher doses versus sham to lower dose versus sham, as well as for studies with higher doses versus calcification and lower doses versus calcifications. Ioppolo 2013 only synthesised the data for calcific deposit resolution for meta‐analysis. We identified two other meta‐analysis of ESWT; however, one only compared high‐dose to low‐dose therapy (Verstraelen 2014) and one pooled data for ESWT versus any other treatment (Vavken 2009). Therefore, to our knowledge ours is the most comprehensive review of shock wave therapy for rotator cuff disease.

Our conclusions about the benefits and harms of ESWT are consistent with other reviews in that it is likely to help resolve calcification deposition, but that this is of uncertain clinical significance. Our review also suggests that higher‐dose therapy may be more beneficial than lower‐dose therapy. Where our review differs, is that Bannuru 2014 and Ioppolo 2013 both recommend ESWT as an effective treatment over sham. These discrepancies appear to derive from how these reviews handled their data. Due to the high heterogeneity of studies, Bannuru 2014 did not synthesise the data from its included studies for meta‐analysis. Instead it appears to have based its recommendations on visualisations of the mean and 95% CIs for studies, and further narrowed its recommendations to "high‐dose" studies including only people with calcifications. These results should be interpreted cautiously, however, as even within these high‐dose trials treatment regimens varied greatly. Furthermore, from the published information, it was not possible to determine which time points Bannuru 2014 was referring to, which groups it extracted its data for (as one included high‐dose trial had three arms) and it should be noted that they considered a trial which compared ESWT to no treatment as sham, where our review considered no treatment at all as not equitable to a sham treatment. Finally, due to the great differences between treatment regimens, our review did not pool all trials with calcifications, but only used trials which reported data separately for people with and without calcifications to consider the potential different effectiveness of ESWT on these groups. As for Ioppolo 2013, the study authors did not synthesise data for outcomes other than calcification resorption for meta‐analysis. Their recommendations about the effectiveness of ESWT over sham for pain and function outcomes are based on the mean change in mean for the treatment groups in their included studies' outcome scores (such as VAS or Constant score), but did not include considerations of CIs or MDs. Meanwhile, our review based its recommendations on how ESWT performed when compared to sham on the MD between treatment and control groups, and considered that for a change to be clinically important its 95% CIs must not have left the range of clinical importance.

Finally, discrepancies over the recommendations that can be made from the results of these meta‐analyses appear to be driven by less frequent consideration of the overall certainty of evidence in these reviews (i.e. while study risk of bias was assessed, other domains of the GRADE approach (imprecision, inconsistency, indirectness and publication bias) were not).

Figure 1

Study flow diagram.

Figure 2

Risk of bias summary: review authors' judgements about each risk of bias item for each included study.

Analysis 1.1

Comparison 1 Shock wave therapy (ESWT) versus placebo, Outcome 1 Proportion of participants with ≥ 50% improvement in pain.

Analysis 1.2

Comparison 1 Shock wave therapy (ESWT) versus placebo, Outcome 2 Mean pain (various scales, lower score indicates less pain).

Analysis 1.3

Comparison 1 Shock wave therapy (ESWT) versus placebo, Outcome 3 Mean function (various scales).

Analysis 1.4

Comparison 1 Shock wave therapy (ESWT) versus placebo, Outcome 4 Treatment success.

Analysis 1.5

Comparison 1 Shock wave therapy (ESWT) versus placebo, Outcome 5 Withdrawals due to adverse events and treatment intolerance.

Analysis 1.6

Comparison 1 Shock wave therapy (ESWT) versus placebo, Outcome 6 Total withdrawals.

Analysis 1.7

Comparison 1 Shock wave therapy (ESWT) versus placebo, Outcome 7 Proportion of participants with adverse events.

Analysis 1.8

Comparison 1 Shock wave therapy (ESWT) versus placebo, Outcome 8 Calcification size (complete resolution).

Analysis 1.9

Comparison 1 Shock wave therapy (ESWT) versus placebo, Outcome 9 Calcification size (partial resolution).

Analysis 1.10

Comparison 1 Shock wave therapy (ESWT) versus placebo, Outcome 10 Mean or change in mean calcification width (mm).

Analysis 1.11

Comparison 1 Shock wave therapy (ESWT) versus placebo, Outcome 11 Subgroup analysis: pain (various scales, lower score indicates less pain).

Analysis 1.12

Comparison 1 Shock wave therapy (ESWT) versus placebo, Outcome 12 Subgroup: function (various scales, higher score is better function).

Analysis 2.1

Comparison 2 Shock wave therapy (ESWT) versus no treatment, Outcome 1 Mean function (Constant score 0–100, 100 indicating best).

Analysis 2.2

Comparison 2 Shock wave therapy (ESWT) versus no treatment, Outcome 2 Treatment success as determined by participant.

Analysis 2.3

Comparison 2 Shock wave therapy (ESWT) versus no treatment, Outcome 3 Calcification size (complete resolution).

Analysis 3.1

Comparison 3 Shock wave therapy (ESWT) versus ultrasound‐guided needling with glucocorticoid, Outcome 1 Mean calcification size.

Analysis 3.2

Comparison 3 Shock wave therapy (ESWT) versus ultrasound‐guided needling with glucocorticoid, Outcome 2 Calcification size (complete resolution).

Analysis 3.3

Comparison 3 Shock wave therapy (ESWT) versus ultrasound‐guided needling with glucocorticoid, Outcome 3 Calcification size (partial resolution).

Analysis 4.1

Comparison 4 Radial shock wave therapy (RSWT) versus ultrasound‐guided needling with corticosteroid, Outcome 1 Mean pain (Numerical Rating Scale, 0–10, higher score indicating worse pain)).

Analysis 4.2

Comparison 4 Radial shock wave therapy (RSWT) versus ultrasound‐guided needling with corticosteroid, Outcome 2 Function (Constant score, 0–100, higher score indicating better function).

Analysis 4.3

Comparison 4 Radial shock wave therapy (RSWT) versus ultrasound‐guided needling with corticosteroid, Outcome 3 Function (Oxford Score 12–60).

Analysis 4.4

Comparison 4 Radial shock wave therapy (RSWT) versus ultrasound‐guided needling with corticosteroid, Outcome 4 Treatment success (proportion of participants with no complaints).

Analysis 4.5

Comparison 4 Radial shock wave therapy (RSWT) versus ultrasound‐guided needling with corticosteroid, Outcome 5 Proportion of participants with adverse events.

Analysis 4.6

Comparison 4 Radial shock wave therapy (RSWT) versus ultrasound‐guided needling with corticosteroid, Outcome 6 Calcification size (complete resolution).

Analysis 5.1

Comparison 5 Radial extracorporeal shock wave therapy (rESWT) versus supervised exercises, Outcome 1 Mean pain (9‐point Likert, 9 is most pain).

Analysis 5.2

Comparison 5 Radial extracorporeal shock wave therapy (rESWT) versus supervised exercises, Outcome 2 Mean function (SPADI 0–100, 100 is best).

Analysis 5.3

Comparison 5 Radial extracorporeal shock wave therapy (rESWT) versus supervised exercises, Outcome 3 Proportion of participants who withdrew due to adverse events.

Analysis 5.4

Comparison 5 Radial extracorporeal shock wave therapy (rESWT) versus supervised exercises, Outcome 4 Proportion of participants who experienced adverse events.

Analysis 5.5

Comparison 5 Radial extracorporeal shock wave therapy (rESWT) versus supervised exercises, Outcome 5 Active range of abduction.

Analysis 6.1

Comparison 6 Extracorporeal shock wave therapy (ESWT) versus ultrasound‐guided percutaneous lavage, Outcome 1 Pain (VAS 0–10, higher score indicating worse pain).

Analysis 6.2

Comparison 6 Extracorporeal shock wave therapy (ESWT) versus ultrasound‐guided percutaneous lavage, Outcome 2 Treatment success (pain free).

Analysis 6.3

Comparison 6 Extracorporeal shock wave therapy (ESWT) versus ultrasound‐guided percutaneous lavage, Outcome 3 Proportion of participants with adverse events.

Analysis 6.4

Comparison 6 Extracorporeal shock wave therapy (ESWT) versus ultrasound‐guided percutaneous lavage, Outcome 4 Calcification size.

Analysis 6.5

Comparison 6 Extracorporeal shock wave therapy (ESWT) versus ultrasound‐guided percutaneous lavage, Outcome 5 Calcification size (proportion with complete resolution).

Analysis 7.1

Comparison 7 Extracorporeal shock wave therapy (ESWT) versus transcutaneous electrical nerve stimulation (TENS), Outcome 1 Change in mean pain from baseline (0–10 VAS, 0 is no pain).

Analysis 7.2

Comparison 7 Extracorporeal shock wave therapy (ESWT) versus transcutaneous electrical nerve stimulation (TENS), Outcome 2 Mean function (Constant score 0–100, 0 is worst and 100 is best).

Analysis 7.3

Comparison 7 Extracorporeal shock wave therapy (ESWT) versus transcutaneous electrical nerve stimulation (TENS), Outcome 3 Withdrawals.

Analysis 7.4

Comparison 7 Extracorporeal shock wave therapy (ESWT) versus transcutaneous electrical nerve stimulation (TENS), Outcome 4 Proportion of participants with adverse events.

Analysis 7.5

Comparison 7 Extracorporeal shock wave therapy (ESWT) versus transcutaneous electrical nerve stimulation (TENS), Outcome 5 Reduction in calcification size (mm).

Analysis 8.1

Comparison 8 Extracorporeal shock wave therapy (ESWT) high dose versus ESWT low dose, Outcome 1 Mean pain (various scales, lower score indicates less pain).

Analysis 8.2

Comparison 8 Extracorporeal shock wave therapy (ESWT) high dose versus ESWT low dose, Outcome 2 Mean function (various scales, higher score is better function).

Analysis 8.3

Comparison 8 Extracorporeal shock wave therapy (ESWT) high dose versus ESWT low dose, Outcome 3 Treatment success as determined by participant.

Analysis 8.4

Comparison 8 Extracorporeal shock wave therapy (ESWT) high dose versus ESWT low dose, Outcome 4 Withdrawals.

Analysis 8.5

Comparison 8 Extracorporeal shock wave therapy (ESWT) high dose versus ESWT low dose, Outcome 5 Proportion of participants who experienced adverse events.

Analysis 8.6

Comparison 8 Extracorporeal shock wave therapy (ESWT) high dose versus ESWT low dose, Outcome 6 Range of movement (University of California at Los Angeles subscore, active flexion measured in degrees).

Analysis 8.7

Comparison 8 Extracorporeal shock wave therapy (ESWT) high dose versus ESWT low dose, Outcome 7 Resolution of calcification.

Analysis 8.8

Comparison 8 Extracorporeal shock wave therapy (ESWT) high dose versus ESWT low dose, Outcome 8 Partial resolution of calcification.

Analysis 8.9

Comparison 8 Extracorporeal shock wave therapy (ESWT) high dose versus ESWT low dose, Outcome 9 Calcification size (mm).

Analysis 8.10

Comparison 8 Extracorporeal shock wave therapy (ESWT) high dose versus ESWT low dose, Outcome 10 Calcification size (> 80% reduction of calcified surface on anteroposterior view).

Analysis 9.1

Comparison 9 Extracorporeal shock wave therapy (ESWT) two sessions versus ESWT one session, Outcome 1 Mean function (Constant score, 0–100, 100 is best).

Analysis 9.2

Comparison 9 Extracorporeal shock wave therapy (ESWT) two sessions versus ESWT one session, Outcome 2 Treatment success as determined by participant.

Analysis 9.3

Comparison 9 Extracorporeal shock wave therapy (ESWT) two sessions versus ESWT one session, Outcome 3 Resolution of calcification.

Analysis 10.1

Comparison 10 Extracorporeal shock wave therapy (ESWT) calcification‐focused versus ESWT supraspinatus origin‐focused, Outcome 1 Mean pain (0–10 point NRS, 0 is no pain).

Analysis 10.2

Comparison 10 Extracorporeal shock wave therapy (ESWT) calcification‐focused versus ESWT supraspinatus origin‐focused, Outcome 2 Mean function (Constant score 0–100, 100 is best).

Analysis 10.3

Comparison 10 Extracorporeal shock wave therapy (ESWT) calcification‐focused versus ESWT supraspinatus origin‐focused, Outcome 3 Treatment success as determined by participant satisfaction.

Analysis 10.4

Comparison 10 Extracorporeal shock wave therapy (ESWT) calcification‐focused versus ESWT supraspinatus origin‐focused, Outcome 4 Calcification size (complete resolution).

Analysis 11.1

Comparison 11 Extracorporeal shock wave therapy (ESWT) image‐guided versus ESWT palpation‐guided, Outcome 1 Mean pain (0–100 VAS, 0 is no pain).

Analysis 11.2

Comparison 11 Extracorporeal shock wave therapy (ESWT) image‐guided versus ESWT palpation‐guided, Outcome 2 Mean function (Constant score 0–100, 100 is best).

Analysis 11.3

Comparison 11 Extracorporeal shock wave therapy (ESWT) image‐guided versus ESWT palpation‐guided, Outcome 3 Calcification size (complete resolution).

Analysis 11.4

Comparison 11 Extracorporeal shock wave therapy (ESWT) image‐guided versus ESWT palpation‐guided, Outcome 4 Calcification size (partial resolution).

Analysis 12.1

Comparison 12 Extracorporeal shock wave therapy (ESWT) with hyperextended arm position versus ESWT with neutral arm position, Outcome 1 Mean pain (0–15 VAS, 15 is worst pain).

Analysis 12.2

Comparison 12 Extracorporeal shock wave therapy (ESWT) with hyperextended arm position versus ESWT with neutral arm position, Outcome 2 Mean function (Constant score 0–100, 100 is best).

Analysis 12.3

Comparison 12 Extracorporeal shock wave therapy (ESWT) with hyperextended arm position versus ESWT with neutral arm position, Outcome 3 Calcification size (> 80% reduction of calcified surface on anteroposterior view).

Analysis 13.1

Comparison 13 Extracorporeal shock wave therapy (ESWT) and exercise and advice versus exercise and advice, Outcome 1 Mean function (Constant score 0–100, 100 is best).

Analysis 14.1

Comparison 14 Shock wave therapy (ESWT) versus ultrasound guided hyaluronic acid (HA) injection, Outcome 1 Function.

Analysis 15.1

Comparison 15 Radial extracorporeal shock wave therapy (rESWT) plus physiotherapy versus physiotherapy, Outcome 1 Mean pain.

Analysis 15.2

Comparison 15 Radial extracorporeal shock wave therapy (rESWT) plus physiotherapy versus physiotherapy, Outcome 2 Mean function.

Analysis 15.3

Comparison 15 Radial extracorporeal shock wave therapy (rESWT) plus physiotherapy versus physiotherapy, Outcome 3 Range of movement (ROM) flexion.

Analysis 15.4

Comparison 15 Radial extracorporeal shock wave therapy (rESWT) plus physiotherapy versus physiotherapy, Outcome 4 ROM extension.

Analysis 15.5

Comparison 15 Radial extracorporeal shock wave therapy (rESWT) plus physiotherapy versus physiotherapy, Outcome 5 ROM abduction.

Analysis 15.6

Comparison 15 Radial extracorporeal shock wave therapy (rESWT) plus physiotherapy versus physiotherapy, Outcome 6 ROM external rotation.

Summary of findings for the main comparison. Shock wave therapy versus placebo for rotator cuff disease with or without calcification

Shock wave therapy for rotator cuff disease with or without calcification at 3 months
Patient or population: rotator cuff disease with or without calcification Setting: outpatient clinic Intervention: shock wave therapy Comparison: placebo therapy
Outcomes	*Anticipated absolute effects (95% CI)**		Relative effect (95% CI)	№ of participants (studies)	Certainty of the evidence (GRADE)	Comments
Outcomes	Risk with placebo	Risk with shock wave therapy	Relative effect (95% CI)	№ of participants (studies)	Certainty of the evidence (GRADE)	Comments
Pain relief > 50%^a Follow‐up: 3 months	375 per 1000	413 per 1000 (232 to 728)	RR 1.10 (0.62 to 1.94)	74 (1 study)	⊕⊕⊝⊝ Low^b,c	Shockwave therapy may provide no improvement in the number of participants with a pain reduction of 50% or more. Absolute change 4% more had relief (19% fewer to 26% more); relative change 10% more had relief (38% fewer to 94% more); NNTB: NA^d
Pain Multiple scales^e translated to VAS 0–10 (10 was severe pain)^f Follow‐up: 3 months	Mean pain in the control group was 3.02 points^g	Mean pain in the intervention group was 0.78 points better (0.17 better to 1.4 better)	SMD –0.49 (95% CI –0.88 to –0.11)	608 (9 studies)	⊕⊕⊕⊝ Moderate^h	Shockwave therapy probably results in little or no clinically important improvement in pain. Mean pain did not appear to differ in participants with and without calcification: test for subgroup differences: Chi² = 0.25, df = 1 (P = 0.62), I² = 0% Absolute change 8% better (2% to 14% better); relative change 14% better (3% better to 25% better);ⁱ NNTB: 4 (95% CI 2 to 34)^d
Function Multiple scales^e translated to Constant 0–100 scale (100 was best function)f Follow‐up: 3 months	Mean function in the control group was 66 points^g	Mean function in the intervention group was 7.9 points better (1.6 better to 14 better)	SMD 0.62 (95% CI 0.13 to 1.11)	612 (9 studies)	⊕⊕⊕⊝ Moderate^j	Shockwave therapy probably results in little or no clinically important improvement in function. Mean function did not appear to differ in participants with and without calcification: test for subgroup differences: Chi² = 1.00, df = 1 (P = 0.32), I² = 0.1% Absolute change: 8% better (1.6% to 14% better); relative change 12% better (3% to 22% better);ⁱ NNTB: 3 (95% CI 2 to 18)^d
Participant‐reported success Follow‐up: end of studies	255 per 1000	406 per 1000 (222 to 743)	RR 1.59 (0.87 to 2.91)	287 (6 studies)	⊕⊕⊝⊝ Low^b,c	Shockwave therapy may provide no improvement in the number of participants reporting treatment success. Absolute change 15% more had success (3% fewer to 49% more); relative change 59% more (13% fewer to 191% more); NNTB: NA^d
Quality of life	—	—	—	—	—	Not measured
Number of participant withdrawals due to adverse events or treatment intolerance	103 per 1000	77 per 1000 (44 to 135)	RR 0.75 (0.43 to 1.31)	581 (7 studies)	⊕⊕⊝⊝ Low^b,c	We are uncertain if shockwave therapy increases withdrawal rates. Absolute change 3% less events (6% less to 3% more); relative change 25% less (57% less to 31% more); NNTH: NA^d
Number of participants experiencing any adverse event Follow‐up: 12 months	72 per 1000	260 per 1000 (144 to 469)	RR 3.61 (2.00 to 6.52)	295 (5 studies)	⊕⊕⊝⊝ Low^b,c	We are uncertain if shockwave therapy increases adverse events. Absolute difference: 19% more events (7% more to 40% more); relative change: 261% more (100% more to 552% more); NNTH: NA^d
*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; NA: not applicable; NNTB: number needed to treat for an additional beneficial outcome; RR: risk ratio; SMD: standardised mean difference; VAS: Visual Analogue Scale.
GRADE Working Group grades of evidence High certainty: we are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect. Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect.
^aThe a priori outcome was pain relief 30% or greater, which was not reported in any studies; thus we reported pain relief 50% or greater. ^b Downgraded one level due to study limitations (including risk of selection, detection, attrition, and reporting bias). ^cDowngraded one level for imprecision due to wide confidence intervals, or small number of participants or small number of events. ^dNumber needed to treat for an additional beneficial outcome (NNTB), or an additional harmful outcome (NNTH) not applicable (n/a) when result is not statistically significant. NNTB or NNTH for dichotomous outcomes calculated using Cates NNT calculator (www.nntonline.net/visualrx/). NNTB or NNTH for continuous outcomes calculated using Wells Calculator (CMSG editorial office), with an assumed minimal clinical important difference for pain of 1.5 points on 0 to 10 VAS, and for function of 10 points on 0 to 100 Constant score. ^ePain scores: VAS 0 to 10, VAS 0 to 100, Constant Score 0 to 15 (also called Constant score); function scores: Constant‐Murley 0 to 100, Shoulder Pain And Disability Index 0 to 100. ^fTranslated from SMD and 95% CIs to 0 to 10 VAS for pain and 0 to 100 Constant scale for function by multiplying the SMD by the standard deviation (SD) at baseline in the placebo group from Gerdesmeyer 2003 (values were mean (SD) VAS pain 5.6 (1.6), and mean Constant score (SD) 64.2 (12.8). ^gControl group mean (SD) values at 3 months' follow‐up from Gerdesmeyer 2003: values were 3.8 (2.3) on 0 to 10 VAS pain; 74 (15.5) on 0 to 100 Constant function score. ^h Downgraded one level due to study limitations (including risk of selection, detection, and attrition bias). Although this outcome had a high I² (80%), the outcome was not downgraded for inconsistency. This high I² was due to one outlier,Hsu 2008 and removing this outlier removes the statistical heterogeneity (I² = 0%) and does not change the direction of the effect ⁱRelative changes calculated as absolute change (mean difference) divided by mean at baseline in the control group from Gerdesmeyer 2003 (values were 5.6 on 0 to 10 point VAS pain; 64.2 on 0 to 100 Constant score). ^jDowngraded one level due to study limitations (including risk of selection, detection, and attrition bias), and one level due to inconsistency (I² = 91%). Removing the potential extreme outlier reported in Hsu 2008 still left considerable heterogeneity (I² = 72%), additional removal of another, less extreme outlier (Cosentino 2003) resulted in I² = 38%. As we could explain the heterogeneity, we did not downgrade the certainty further.

Summary of findings for the main comparison. Shock wave therapy versus placebo for rotator cuff disease with or without calcification

Table 1. Characteristics of interventions used in included trials

Study ID	Shock wave machine	Type of shock wave	Number, frequency and dose	Comparison	Use of anaesthesia	Number of treatments
Albert 2007	Modulith SLK (Storz Medical AG, Tagerwilen, Switzerland) electromagnetic shock wave generator with fluoroscopic and sonographic guidance	ESWT	High‐dose shock wave: 2500 impulses, frequency 1 Hz for first 200 and 2 Hz thereafter. Goal intensity was maximum energy level tolerated by participant without exceeding 0.45 mJ/mm² per impulse	Low dose: 2500 impulses, frequency 1 Hz for first 200 and 2Hz thereafter. The energy intensity gradually increased from 0.02 mJ/mm² to 0.06 mJ/mm² per shock	None	2 sessions 14 days apart
Cacchio 2006	Physio Shock Wave Therapy device consisting of a control unit, a handpiece with 3 different head applicators and medical air compressor	rESWT	High dose: 2500 impulses per session (500 impulses with pressure 1.5 bar and frequency 10 Hz), EFD 0.10 mJ/mm² and fixed impulse time of 2 ms	Low dose: 25 impulses per session (5 impulses with a pressure of 1.5 bar and frequency of 4.5 Hz and 20 impulses with pressure 2.5 bar and frequency 10 Hz), EFD 0.10 mJ/mm² and fixed impulse time of 2 ms	None	4 sessions 7 days apart
Cosentino 2003	'Orthima' by Direx Medical System Ltd	ESWT	Shock wave: 1200 shocks at 120 shocks/minute of 0.03 mJ/mm²	Placebo: 1200 shocks at 120 shock/minute of 0 mJ/mm²	None	4 sessions 4–7 days apart
De Boer 2017	Masterpuls MP 100 (Storz Medical, Tagerwilen, Switzerland)	rESWT	Shock wave: 500 pulses of 1.5 bar (150 kPa) with a frequency of 4.5 Hz, followed by 2000 pulses of 2.5 bar (250 kPa) with a frequency 10 Hz; EFD)0.10 mJ/mm², duration of pulses was 2 ms	Ultrasound‐guided needling	None	4 sessions, 1 week apart
Del Castillo‐Gonzales 2016	Swiss DolorClast device	ESWT	Shock wave: Total of 2000 impacts (2 series of 1000 each) at frequency 8–10 Hz and EFD 0.20 J/mm²	Ultrasound‐guided percutaneous lavage	None	Twice per week for 4 weeks
Duymaz 2019	ShockMaster 500 device (GymnaUniphy NV, Bilzen, Belgium)	rESWT	Shock wave: 1500 shocks with a frequency of 150 shocks per minute. all participants were treated with a low‐energy density of 0.03 mJ/mm² for the first 5 minutes, which was then progressively increased to 0.28 mJ/mm². Duration of pulses was 10 minutes	Physiotherapy: ultrasound (1.0 MHz, 5 minutes, continuous), TENS (conventional, 20 minutes), shoulder joint ROM and stretching exercises, and ice application	None	1 session weekly for 4 weeks
Engebretsen 2009	Swiss Dolor Clast, EMS	rESWT	Shock wave: 8–12 Hz at 2000 impulses/second with a pressure of 2.5–4.0 bar	Supervised exercises	None	1 session weekly for 4–6 weeks for rESWT OR 2 × 45‐minute sessions weekly for up to 12 weeks for supervised exercises
Farr 2011	Storz Modulith SLK lithotripter in combination with a fluoroscopy‐guided 3D computer‐assisted navigation device	ESWT	High dose: 3200 impulses at 0.3 mJ/mm²; twice	Low dose: 1600 impulses at 0.02 mJ/mm²; once	5 mL xylocaine subacromially	Once only for low dose OR 2 sessions 7 days apart for high dose
Frizziero 2017	Modulith SLK (Storz Medical AG, Tagerwilen, Switzerland)	ESWT	Shock wave (low dose): 1600 impulses at a frequency of 4 Hz not exceeding 0.15 mJ/mm²	Ultrasound‐guided injection with low molecular weight hyaluronic acid	None	Weekly shock wave sessions for 4 weeks OR 1 injection weekly for 3 weeks
Galasso 2012	Modulith SLK system	ESWT	Shock wave: 3000 shocks of 0.068 mJ/mm²	Placebo: Same protocol but with shock wave generator disconnected	Subcutaneous injection of 2 mL of 2% lidocaine above the subacromial space of the affected shoulder prior to each treatment	2 sessions 7 days apart
Gerdesmeyer 2003	Not reported	ESWT	Shock wave (low dose): 6000 shocks at 120 impulses/minute of 0.08 mJ/mm²	High dose: 6000 shocks at 120 impulses/minute of 0.32 mJ/mm² OR Placebo: 1500 shocks at 120 impulses/minute of 0.32 mJ/mm² with participant insulated from shock waves	None	2 sessions 12–16 days apart
Haake 2002	Adapted shock wave generator Storz Minilith SL‐1 (Storz Medical AG, CH 8280 Kreuzlingen, Switzerland)	ESWT	At site of calcification: 2000 impulses of a positive EFD 0.35 mJ/mm² measured with a membrane hydrophone (equivalent to 0.78 mJ/mm² measured with a fibreoptic hydrophone) at 120 impulses/minute	Supraspinatus site: 2000 impulses of a positive EFD 0.35 mJ/mm² measured with a membrane hydrophone (equivalent to 0.78 mJ/mm² measured with a fibreoptic hydrophone) at 120 impulses/minute	15 mL mepivacaine 1% subacromially	2 sessions 7 days apart
Hearnden 2009	Not reported	ESWT	Shock wave: 2000 shocks of 0.28 mJ/mm²	Placebo: 20 shocks of 0.03 mJ/mm²	20 mL of 0.5% marcaine at site of calcific deposit	1 session
Hsu 2008	OrthoWave machine (MTS, Konstanz, Germany)	ESWT	Shock wave: 1000 shocks at 2 wave pulses/second of 0.55 mJ/mm²	Placebo: dummy electrode	10 mL of 2% lidocaine injected into affected area from a lateral approach with a 24‐gauge needle	2 sessions 14 days apart
Ioppolo 2012	ESWT (Modulith SLK system, Storz Medical, Tager‐wilen, Switzerland) equipped with an in‐line ultrasound positioning system on the target zone	ESWT	Low dose: 2400 impulses at 0.10 mJ/mm²	High dose: 2400 impulses at 0.20 mJ/mm²	None	4 sessions 7 days apart
Kim 2014	Not reported	ESWT	Shock wave: 1000 impulses, 0.32 mJ/mm²	Glucocorticoid needling 1 mL Depo‐Medrol (glucocorticoid) ultrasound guidance	2% lidocaine in the corticosteroid group	3 sessions 1 week apart for ESWT OR 1 steroid injection
Kolk 2013	Swiss DolorClast radial shock wave device (EMS Electro Medical Systems, Nyon, Switzerland)	rESWT	Shock wave: 2000 impulses of 0.11 mJ/mm²	Placebo: 2000 impulses of 0.11 mJ/mm² with a sham probe	None	3 sessions 10–14 days apart
Kvalvaag 2017	EMS Swiss DolorClast/Enimed	rESWT	Shock wave: 2000 impulses at 0.35 mJ/mm² pressure 1.5–3 bar, depending on what the participant tolerated	Placebo: 2000 impulses at 0.35 mJ/mm² with a sham probe	None	1 session weekly for 4 weeks
Li 2017	Pain Treatment System of Radial shock wave Device (Sonothera, Hanil Tm Co. Ltd, Korea)	ESWT	Shock wave: 3000 pulses of 0.11 mJ/mm² at frequency 15 Hz. Pressure 3 bar	Placebo: identical‐looking placebo probe used	None	5 sessions, 3 days apart
Loew 1999	Electrohydraulic lithotripter (MFL 5000; Philips, Hamburg, Germany)	ESWT	Group 1: 1 dose of 2000 impulses of 0.1 mJ/mm² Group 2: 1 dose of 2000 impulses of 0.3 mJ/mm² Group 3: 2 doses of 2000 impulses of 0.3 mJ/mm² 1 week apart	No treatment	15–20 mL bupivacaine hydrochloride	1 session OR 2 sessions 1 week apart
Melegati 2000	Epos Ultra electromagnetic apparatus fitted with a 7.5 MHz linear echographic sound	ESWT	200 shots of 0.22 mJ/mm² reached in 400 shots	Kinesitherapy	None	3 sessions 7 days apart for ESWT OR 6 × 40‐minute sessions 3 weeks apart for kinesitherapy
Pan 2003	Orthospec (Medispec Ltd, Germantown, MD, USA)	ESWT	2000 shock waves at 2 Hz of 0.26–0.32 mJ/mm²	TENS	None	2 sessions 14 days apart for ESWT OR 3 times a week for 4 weeks for TENS
Perlick 2003	Siemens Lithostar‐Lithotripter	ESWT	2000 impulses of 0.23 mJ/mm²	2000 impulses of 0.42 mJ/mm²	10 mL bupivacaine hydrochloride 0.5%	2 sessions 3 weeks apart
Peters 2004	The miniaturised shock wave source Minilith (15 cm diameter, 15 cm length) (Stroz Medical, Switzerland) with an in‐line ultrasound device	ESWT	1500 impulses of 0.15 mJ/mm²	1500 impulses of 0.44 mJ/mm² OR system turned off	None	1–5 sessions at 6‐week intervals
Pleiner 2004	Electrohydraulic system (Orthospec, Medispec Inc, Montgomery Village, MD, USA)	ESWT	High dose: 2 × 2000 impulses at frequency 2.5 Hz, dose 0.28 mJ/mm²	Placebo 2 × 2000 impulses at frequency 2.5 Hz, dose < 0.07 mJ/mm² dampened with a foam membrane	None	2 sessions
Rompe 1998	ESWT with an experimental device characterised by the integration of an electromagnetic shock wave generator and a mobile fluoroscopy unit (Siemens AG, 91052 Erlangen, Germany)	ESWT	1500 impulses of 0.06 mJ/mm²	1500 impulses of 0.28 mJ/mm²	None	1 session
Sabeti 2007	Lithotripter (Storz Modulith SLK, Storz Medical Products, Kreuzlingen, Switzerland)	ESWT	1000 impulses of 0.08 mJ/mm²	2000 impulses of 0.02 mJ/mm²	5 mL Xyloneural subacromially	3 sessions 7 days apart for low dose OR 2 sessions 7 days apart for higher dose
Sabeti‐Aschraf 2005	Lithotripter (Modulith SLK, Storz Medical Products, Kreuzlingen, Switzerland)	ESWT	1000 impulses of 0.08 mJ/mm² with frequency 4 Hz	1000 impulses of 0.08 mJ/mm² with frequency 4 Hz	None	3 sessions 7 days apart
Schmitt 2001	Storz Minilith SL 1 (Storz Medical AG, Kreuzlingen, Switzerland)	ESWT	2000 impulses at 120 impulses/minute of 0.11 mJ/mm²	2000 impulses at 120 impulses/minute of 0.11 mJ/mm² with the participant insulated from the shock waves	10 mL mepivacaine subacromially	3 sessions 7 days apart
Schofer 2009	Minilith SL 1 shock wave generator (Storz Medical, Switzerland)	ESWT	2000 impulses at 120 impulses/second of 0.33 mJ/mm²	2000 impulses at 120 impulses/second of 0.78 mJ/mm²	10 mL mepivacaine 1% subacromially	3 sessions 7 days apart
Speed 2002	Sonocur Plus Unit (Siemens, Munich, Germany)	ESWT	1500 impulses of 0.12 mJ/mm²	1500 impulses of 0.04 mJ/mm² with the machine head deflated, no contact gel applied and standard skin contact avoided	None	3 sessions 1 month apart
Tornese 2011	Electromagnetic lithotriptor (Epos Ultra; Dornier MedTech Wessling, Germany) fitted with a linear ultrasonographic probe	ESWT	1800 pulses of up to 0.22 mJ/mm² which was reached within 400 impulses	1800 pulses of up to 0.22 mJ/mm² which was reached within 400 impulses	None	3 sessions 7 days apart
EFD: energy fluctuation density; ESWT: extracorporeal shock wave therapy; rESWT: radial extracorporeal shock wave therapy; ROM: range of movement; TENS: transcutaneous electrical nerve stimulation.

Table 1. Characteristics of interventions used in included trials

Table 2. Shock wave therapy versus placebo secondary outcomes

Outcome	Number of studies	Number of participants: shock wave	Number of participants: placebo	Statistic random‐effects Mantel‐Haenszel	Effect estimate (95% CI)
Proportion achieving pain score below 30/100 mm on VAS	0	Not reported	Not reported	Not reported	Not reported
Range of movement	0	Not reported	Not reported	Not reported	Not reported
Mean change in calcification width (mm) at 3 months	1	46	42	Mean difference (95% CI)	–26.00 (–85.77 to 33.77)
Proportion with complete calcification resolution	3	91	68	Risk ratio (95% CI)	4.78 (1.31 to 17.39)
Proportion with partial calcification partial resolution	3	91	68	Risk ratio (95% CI)	3.41 (0.95 to 12.23)
CI: confidence interval; VAS: Visual Analogue Scale.

Table 2. Shock wave therapy versus placebo secondary outcomes

Table 3. Outcome Reporting Bias In Trials (ORBIT) matrix

Study ID	Major outcomes
Study ID	Participant‐reported pain relief ≥ 50%	Pain	Function or disability	Treatment success	Quality of life	Withdrawal due to adverse events	Adverse events
Albert 2007	?	Full	Full	Full	?	?	Full
Cacchio 2006	?	Full	Full	Full	?	Full	Full
Cosentino 2003	?	Partial	Full	?	?	?	Full
De Boer 2017	?	Full	Full	Full	?	?	Full
Del Castillo‐Gonzales 2016	?	Full	?	Full	?	?	Full
Duymaz 2019	?	Full	Full	?	?	?	?
Engebretsen 2009	?	Full	Full	?	?	Full	Full
Farr 2011	?	Full	Full	?	?	?	Full
Frizziero 2017	?	Partial	Full	?	?	?	?
Galasso 2012	?	Full	Full	Full	?	Full	Full
Gerdesmeyer 2003	?	Full	Full	Full	?	?	Full
Haake 2002	?	Full	Full	Full	?	?	Full
Hearnden 2009	?	Partial	Partial	Full	?	?	Partial
Hsu 2008	?	Full	Full	Full	?	?	Full
Ioppolo 2012	?	Full	Full	?	?	?	?
Kim 2014	?	Partial	Partial	?	?	?	?
Kolk 2013	?	Full	Full	?	?	?	?
Kvalvaag 2017	?	Full	Full	?	?	Full	Partial
Li 2017	?	Full	Full	?	?	?	Full
Loew 1999	?	Not measured	Full	Full	?	?	?
Melegati 2000	?	Not measured	Full	?	?	?	?
Pan 2003	?	Full	Full	?	?	Full	Full
Perlick 2003	?	Full	Partial	?	?	?	Full
Peters 2004	?	?	?	Full	?	Full	Full
Pleiner 2004	?	Full	Measured	?	?	?	?
Rompe 1998	?	Not measured	Partial	Full	?	?	?
Sabeti 2007	?	Full	Full	Full	?	?	?
Sabeti‐Aschraf 2005	?	Full	Full	?	?	?	Full
Schmitt 2001	?	Full	Full	Full	?	Full	Full
Schofer 2009	?	Full	Full	?	?	?	Full
Speed 2002	Full	Partial	Full	Full	?	Full	Full
Tornese 2011	?	Full	Full	?	?	?	?
'Full': sufficient data for inclusion in a meta‐analysis was reported (e.g. mean, standard deviation and sample size per group for continuous outcomes). 'Partial': insufficient data for inclusion in a meta‐analysis was reported (e.g. means only, with no measures of variance). 'Measured': outcome was measured but no outcome data was reported. 'Not measured': outcome was not measured by the trialists. '?': unclear whether the outcome was measured or not (as a trial protocol was unavailable).

Table 3. Outcome Reporting Bias In Trials (ORBIT) matrix

Comparison 1. Shock wave therapy (ESWT) versus placebo

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Proportion of participants with ≥ 50% improvement in pain Show forest plot	1	74	Risk Ratio (M‐H, Random, 95% CI)	1.10 [0.62, 1.94]

2 Mean pain (various scales, lower score indicates less pain) Show forest plot	9		Mean Difference (IV, Random, 95% CI)	Subtotals only

2.1 6 weeks	6	304	Mean Difference (IV, Random, 95% CI)	‐2.10 [‐3.58, ‐0.62]
2.2 3 months	9	608	Mean Difference (IV, Random, 95% CI)	‐1.95 [‐3.45, ‐0.44]
2.3 6 months	5	419	Mean Difference (IV, Random, 95% CI)	‐1.53 [‐3.49, 0.43]
2.4 12 months	3	155	Mean Difference (IV, Random, 95% CI)	‐2.42 [‐5.79, 0.95]
3 Mean function (various scales) Show forest plot	11		Std. Mean Difference (IV, Random, 95% CI)	Subtotals only

3.1 6 weeks	7	374	Std. Mean Difference (IV, Random, 95% CI)	0.79 [0.30, 1.28]
3.2 3 months	9	612	Std. Mean Difference (IV, Random, 95% CI)	0.62 [0.13, 1.11]
3.3 6 months	7	486	Std. Mean Difference (IV, Random, 95% CI)	0.91 [0.24, 1.57]
3.4 12 months	3	155	Std. Mean Difference (IV, Random, 95% CI)	1.45 [‐0.21, 3.12]
4 Treatment success Show forest plot	6	287	Risk Ratio (M‐H, Random, 95% CI)	1.59 [0.87, 2.91]

5 Withdrawals due to adverse events and treatment intolerance Show forest plot	7	581	Risk Ratio (M‐H, Random, 95% CI)	0.75 [0.43, 1.31]

6 Total withdrawals Show forest plot	8	621	Risk Ratio (M‐H, Fixed, 95% CI)	0.74 [0.52, 1.07]

7 Proportion of participants with adverse events Show forest plot	5	295	Risk Ratio (M‐H, Random, 95% CI)	3.61 [2.00, 6.52]

8 Calcification size (complete resolution) Show forest plot	3	159	Risk Ratio (M‐H, Random, 95% CI)	4.78 [1.31, 17.39]

9 Calcification size (partial resolution) Show forest plot	3	159	Risk Ratio (M‐H, Random, 95% CI)	3.41 [0.95, 12.23]

10 Mean or change in mean calcification width (mm) Show forest plot	2		Mean Difference (IV, Random, 95% CI)	Subtotals only

10.1 3 months	1	88	Mean Difference (IV, Random, 95% CI)	‐24.00 [‐85.77, 33.77]
10.2 6 months	1	87	Mean Difference (IV, Random, 95% CI)	‐36.7 [‐94.86, 21.46]
10.3 12 months	2	122	Mean Difference (IV, Random, 95% CI)	‐21.76 [‐60.99, 17.46]
11 Subgroup analysis: pain (various scales, lower score indicates less pain) Show forest plot	9		Std. Mean Difference (IV, Random, 95% CI)	Subtotals only

11.1 Calcification	5	256	Std. Mean Difference (IV, Random, 95% CI)	‐0.59 [‐1.33, 0.14]
11.2 No calcification	5	253	Std. Mean Difference (IV, Random, 95% CI)	‐0.39 [‐0.70, ‐0.09]
12 Subgroup: function (various scales, higher score is better function) Show forest plot	9		Std. Mean Difference (IV, Random, 95% CI)	Subtotals only

12.1 Calcification	5	260	Std. Mean Difference (IV, Random, 95% CI)	0.84 [‐0.20, 1.89]
12.2 No calcification	5	253	Std. Mean Difference (IV, Random, 95% CI)	0.29 [‐0.04, 0.61]

Comparison 1. Shock wave therapy (ESWT) versus placebo

Comparison 2. Shock wave therapy (ESWT) versus no treatment

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Mean function (Constant score 0–100, 100 indicating best) Show forest plot	1		Mean Difference (IV, Random, 95% CI)	Subtotals only

1.1 3 months	1	40	Mean Difference (IV, Random, 95% CI)	3.80 [‐6.33, 13.93]
2 Treatment success as determined by participant Show forest plot	1		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only

3 Calcification size (complete resolution) Show forest plot	1		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only

Comparison 2. Shock wave therapy (ESWT) versus no treatment

Comparison 3. Shock wave therapy (ESWT) versus ultrasound‐guided needling with glucocorticoid

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Mean calcification size Show forest plot	1		Mean Difference (IV, Fixed, 95% CI)	Totals not selected

2 Calcification size (complete resolution) Show forest plot	1	54	Risk Ratio (M‐H, Fixed, 95% CI)	0.57 [0.35, 0.95]

3 Calcification size (partial resolution) Show forest plot	1	54	Risk Ratio (M‐H, Fixed, 95% CI)	1.44 [0.38, 5.42]

Comparison 3. Shock wave therapy (ESWT) versus ultrasound‐guided needling with glucocorticoid

Comparison 4. Radial shock wave therapy (RSWT) versus ultrasound‐guided needling with corticosteroid

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Mean pain (Numerical Rating Scale, 0–10, higher score indicating worse pain)) Show forest plot	1		Mean Difference (IV, Random, 95% CI)	Subtotals only

1.1 6 weeks	1	25	Mean Difference (IV, Random, 95% CI)	1.60 [0.13, 3.07]
1.2 12 months	1	19	Mean Difference (IV, Random, 95% CI)	0.20 [‐2.05, 2.45]
2 Function (Constant score, 0–100, higher score indicating better function) Show forest plot	1		Mean Difference (IV, Random, 95% CI)	Subtotals only

2.1 6 weeks	1	25	Mean Difference (IV, Random, 95% CI)	‐11.70 [‐24.79, 1.39]
3 Function (Oxford Score 12–60) Show forest plot	1		Mean Difference (IV, Random, 95% CI)	Subtotals only

3.1 6 weeks	1	25	Mean Difference (IV, Random, 95% CI)	‐2.30 [‐9.30, 4.70]
3.2 12 months	1	19	Mean Difference (IV, Random, 95% CI)	‐4.10 [‐15.74, 7.54]
4 Treatment success (proportion of participants with no complaints) Show forest plot	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only

5 Proportion of participants with adverse events Show forest plot	1		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only

6 Calcification size (complete resolution) Show forest plot	1		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only

Comparison 4. Radial shock wave therapy (RSWT) versus ultrasound‐guided needling with corticosteroid

Comparison 5. Radial extracorporeal shock wave therapy (rESWT) versus supervised exercises

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Mean pain (9‐point Likert, 9 is most pain) Show forest plot	1		Mean Difference (IV, Random, 95% CI)	Subtotals only

1.1 6 weeks	1	90	Mean Difference (IV, Random, 95% CI)	0.30 [‐0.53, 1.13]
1.2 3 months	1	102	Mean Difference (IV, Random, 95% CI)	0.40 [‐0.36, 1.16]
1.3 6 months	1	100	Mean Difference (IV, Random, 95% CI)	0.20 [‐0.56, 0.96]
1.4 12 months	1	97	Mean Difference (IV, Random, 95% CI)	0.5 [‐0.20, 1.20]
2 Mean function (SPADI 0–100, 100 is best) Show forest plot	1		Mean Difference (IV, Random, 95% CI)	Totals not selected

2.1 6 weeks	1		Mean Difference (IV, Random, 95% CI)	0.0 [0.0, 0.0]
2.2 3 months	1		Mean Difference (IV, Random, 95% CI)	0.0 [0.0, 0.0]
2.3 6 months	1		Mean Difference (IV, Random, 95% CI)	0.0 [0.0, 0.0]
2.4 12 months	1		Mean Difference (IV, Random, 95% CI)	0.0 [0.0, 0.0]
3 Proportion of participants who withdrew due to adverse events Show forest plot	1	104	Risk Ratio (M‐H, Fixed, 95% CI)	3.0 [0.32, 27.91]

4 Proportion of participants who experienced adverse events Show forest plot	1		Risk Ratio (M‐H, Random, 95% CI)	Totals not selected

5 Active range of abduction Show forest plot	1		Mean Difference (IV, Random, 95% CI)	Subtotals only

5.1 3 months	1	104	Mean Difference (IV, Random, 95% CI)	‐1.95 [‐10.50, 6.60]
5.2 6 months	1	104	Mean Difference (IV, Random, 95% CI)	‐11.82 [‐25.37, 1.73]

Comparison 5. Radial extracorporeal shock wave therapy (rESWT) versus supervised exercises

Comparison 6. Extracorporeal shock wave therapy (ESWT) versus ultrasound‐guided percutaneous lavage

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Pain (VAS 0–10, higher score indicating worse pain) Show forest plot	1		Mean Difference (IV, Random, 95% CI)	Subtotals only

1.1 6 weeks	1	201	Mean Difference (IV, Random, 95% CI)	‐0.10 [‐0.26, 0.06]
1.2 3 months	1	201	Mean Difference (IV, Random, 95% CI)	1.9 [1.54, 2.26]
1.3 6 months	1	201	Mean Difference (IV, Random, 95% CI)	1.80 [1.36, 2.24]
1.4 12 months	1	201	Mean Difference (IV, Random, 95% CI)	1.90 [1.34, 2.46]
2 Treatment success (pain free) Show forest plot	1	201	Risk Ratio (M‐H, Random, 95% CI)	0.91 [0.81, 1.03]

3 Proportion of participants with adverse events Show forest plot	1	243	Risk Ratio (M‐H, Random, 95% CI)	0.08 [0.00, 1.36]

4 Calcification size Show forest plot	1		Mean Difference (IV, Random, 95% CI)	Subtotals only

4.1 6 weeks	1	201	Mean Difference (IV, Random, 95% CI)	‐2.0 [‐2.94, ‐1.06]
4.2 3 months	1	201	Mean Difference (IV, Random, 95% CI)	2.0 [1.17, 2.83]
4.3 6 months	1	201	Mean Difference (IV, Random, 95% CI)	2.40 [1.44, 3.36]
4.4 12 months	1	201	Mean Difference (IV, Random, 95% CI)	3.1 [2.07, 4.13]
5 Calcification size (proportion with complete resolution) Show forest plot	1	201	Risk Ratio (M‐H, Random, 95% CI)	0.65 [0.53, 0.80]

Comparison 6. Extracorporeal shock wave therapy (ESWT) versus ultrasound‐guided percutaneous lavage

Comparison 7. Extracorporeal shock wave therapy (ESWT) versus transcutaneous electrical nerve stimulation (TENS)

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Change in mean pain from baseline (0–10 VAS, 0 is no pain) Show forest plot	1		Mean Difference (IV, Random, 95% CI)	Subtotals only

1.1 6 weeks	1	62	Mean Difference (IV, Random, 95% CI)	‐1.9 [‐2.98, ‐0.82]
1.2 3 months	1	62	Mean Difference (IV, Random, 95% CI)	‐2.34 [‐3.53, ‐1.15]
2 Mean function (Constant score 0–100, 0 is worst and 100 is best) Show forest plot	1		Mean Difference (IV, Random, 95% CI)	Totals not selected

2.1 6 weeks	1		Mean Difference (IV, Random, 95% CI)	0.0 [0.0, 0.0]
2.2 3 months	1		Mean Difference (IV, Random, 95% CI)	0.0 [0.0, 0.0]
3 Withdrawals Show forest plot	1	62	Risk Ratio (M‐H, Random, 95% CI)	0.29 [0.01, 6.95]

4 Proportion of participants with adverse events Show forest plot	1		Risk Ratio (M‐H, Random, 95% CI)	Totals not selected

5 Reduction in calcification size (mm) Show forest plot	1		Mean Difference (IV, Random, 95% CI)	Totals not selected

5.1 6 weeks	1		Mean Difference (IV, Random, 95% CI)	0.0 [0.0, 0.0]
5.2 3 months	1		Mean Difference (IV, Random, 95% CI)	0.0 [0.0, 0.0]

Comparison 7. Extracorporeal shock wave therapy (ESWT) versus transcutaneous electrical nerve stimulation (TENS)

Comparison 8. Extracorporeal shock wave therapy (ESWT) high dose versus ESWT low dose

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Mean pain (various scales, lower score indicates less pain) Show forest plot	8		Std. Mean Difference (IV, Random, 95% CI)	Subtotals only

1.1 6 weeks	2	117	Std. Mean Difference (IV, Random, 95% CI)	‐1.73 [‐3.94, 0.48]
1.2 3 months	6	326	Std. Mean Difference (IV, Random, 95% CI)	‐0.26 [‐0.67, 0.16]
1.3 6 months	4	309	Std. Mean Difference (IV, Random, 95% CI)	‐1.66 [‐2.98, ‐0.33]
1.4 12 months	3	196	Std. Mean Difference (IV, Random, 95% CI)	‐0.60 [‐1.39, 0.18]
2 Mean function (various scales, higher score is better function) Show forest plot	10		Std. Mean Difference (IV, Random, 95% CI)	Subtotals only

2.1 6 weeks	2	117	Std. Mean Difference (IV, Random, 95% CI)	3.71 [‐3.71, 11.14]
2.2 3 months	7	366	Std. Mean Difference (IV, Random, 95% CI)	0.31 [0.08, 0.53]
2.3 6 months	5	409	Std. Mean Difference (IV, Random, 95% CI)	2.29 [1.05, 3.52]
2.4 12 months	3	196	Std. Mean Difference (IV, Random, 95% CI)	0.50 [‐0.03, 1.02]
3 Treatment success as determined by participant Show forest plot	6	450	Risk Ratio (M‐H, Random, 95% CI)	2.74 [1.58, 4.77]

4 Withdrawals Show forest plot	1		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only

5 Proportion of participants who experienced adverse events Show forest plot	5	351	Risk Ratio (M‐H, Random, 95% CI)	3.51 [1.53, 8.03]

6 Range of movement (University of California at Los Angeles subscore, active flexion measured in degrees) Show forest plot	1		Mean Difference (IV, Random, 95% CI)	Subtotals only

6.1 6 weeks	1	90	Mean Difference (IV, Random, 95% CI)	49.35 [37.39, 61.31]
6.2 6 months	1	90	Mean Difference (IV, Random, 95% CI)	62.0 [50.59, 73.41]
7 Resolution of calcification Show forest plot	4	281	Risk Ratio (M‐H, Random, 95% CI)	2.91 [1.04, 8.15]

8 Partial resolution of calcification Show forest plot	2	180	Risk Ratio (M‐H, Random, 95% CI)	1.13 [0.73, 1.75]

9 Calcification size (mm) Show forest plot	3		Mean Difference (IV, Random, 95% CI)	Subtotals only

9.1 6 months	3	229	Mean Difference (IV, Random, 95% CI)	‐24.19 [‐44.83, ‐3.55]
9.2 12 months	1	79	Mean Difference (IV, Random, 95% CI)	‐70.70 [‐141.05, ‐0.35]
10 Calcification size (> 80% reduction of calcified surface on anteroposterior view) Show forest plot	1	80	Risk Ratio (M‐H, Random, 95% CI)	3.0 [0.64, 13.98]

Comparison 8. Extracorporeal shock wave therapy (ESWT) high dose versus ESWT low dose

Comparison 9. Extracorporeal shock wave therapy (ESWT) two sessions versus ESWT one session

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Mean function (Constant score, 0–100, 100 is best) Show forest plot	1		Mean Difference (IV, Random, 95% CI)	Subtotals only

1.1 3 months	1	40	Mean Difference (IV, Random, 95% CI)	4.80 [‐3.80, 13.40]
2 Treatment success as determined by participant Show forest plot	1	40	Risk Ratio (M‐H, Random, 95% CI)	1.17 [0.74, 1.85]

3 Resolution of calcification Show forest plot	1	40	Risk Ratio (M‐H, Random, 95% CI)	1.09 [0.64, 1.86]

Comparison 9. Extracorporeal shock wave therapy (ESWT) two sessions versus ESWT one session

Comparison 10. Extracorporeal shock wave therapy (ESWT) calcification‐focused versus ESWT supraspinatus origin‐focused

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Mean pain (0–10 point NRS, 0 is no pain) Show forest plot	1		Mean Difference (IV, Random, 95% CI)	Subtotals only

1.1 3 months	1	47	Mean Difference (IV, Random, 95% CI)	‐1.53 [‐3.24, 0.18]
1.2 12 months	1	49	Mean Difference (IV, Random, 95% CI)	‐2.27 [‐3.49, ‐1.05]
2 Mean function (Constant score 0–100, 100 is best) Show forest plot	1		Mean Difference (IV, Random, 95% CI)	Subtotals only

2.1 6 months	1	47	Mean Difference (IV, Random, 95% CI)	31.51 [16.33, 46.69]
2.2 12 months	1	49	Mean Difference (IV, Random, 95% CI)	32.73 [20.40, 45.06]
3 Treatment success as determined by participant satisfaction Show forest plot	1		Risk Ratio (M‐H, Random, 95% CI)	Totals not selected

4 Calcification size (complete resolution) Show forest plot	1	46	Risk Ratio (M‐H, Random, 95% CI)	1.60 [0.84, 3.07]

Comparison 10. Extracorporeal shock wave therapy (ESWT) calcification‐focused versus ESWT supraspinatus origin‐focused

Comparison 11. Extracorporeal shock wave therapy (ESWT) image‐guided versus ESWT palpation‐guided

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Mean pain (0–100 VAS, 0 is no pain) Show forest plot	1		Mean Difference (IV, Random, 95% CI)	Subtotals only

1.1 3 months	1	50	Mean Difference (IV, Random, 95% CI)	‐15.15 [‐26.62, ‐3.68]
2 Mean function (Constant score 0–100, 100 is best) Show forest plot	1		Mean Difference (IV, Random, 95% CI)	Subtotals only

2.1 3 months	1	50	Mean Difference (IV, Random, 95% CI)	6.48 [‐2.22, 15.18]
3 Calcification size (complete resolution) Show forest plot	1	50	Risk Ratio (M‐H, Random, 95% CI)	6.0 [0.78, 46.29]

4 Calcification size (partial resolution) Show forest plot	1	50	Risk Ratio (M‐H, Random, 95% CI)	1.4 [0.51, 3.82]

Comparison 11. Extracorporeal shock wave therapy (ESWT) image‐guided versus ESWT palpation‐guided

Comparison 12. Extracorporeal shock wave therapy (ESWT) with hyperextended arm position versus ESWT with neutral arm position

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Mean pain (0–15 VAS, 15 is worst pain) Show forest plot	1		Mean Difference (IV, Random, 95% CI)	Subtotals only

1.1 3 months	1	35	Mean Difference (IV, Random, 95% CI)	1.70 [‐0.55, 3.95]
2 Mean function (Constant score 0–100, 100 is best) Show forest plot	1		Mean Difference (IV, Random, 95% CI)	Subtotals only

2.1 3 months	1	35	Mean Difference (IV, Random, 95% CI)	9.0 [0.72, 17.28]
3 Calcification size (> 80% reduction of calcified surface on anteroposterior view) Show forest plot	1	35	Risk Ratio (M‐H, Random, 95% CI)	1.89 [0.92, 3.89]

Comparison 12. Extracorporeal shock wave therapy (ESWT) with hyperextended arm position versus ESWT with neutral arm position

Comparison 13. Extracorporeal shock wave therapy (ESWT) and exercise and advice versus exercise and advice

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Mean function (Constant score 0–100, 100 is best) Show forest plot	1		Mean Difference (IV, Random, 95% CI)	Subtotals only

1.1 12 months	1	60	Mean Difference (IV, Random, 95% CI)	9.35 [4.98, 13.72]

Comparison 13. Extracorporeal shock wave therapy (ESWT) and exercise and advice versus exercise and advice

Comparison 14. Shock wave therapy (ESWT) versus ultrasound guided hyaluronic acid (HA) injection

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Function Show forest plot	1	34	Std. Mean Difference (IV, Fixed, 95% CI)	‐0.26 [‐0.94, 0.41]

1.1 3 months	1	34	Std. Mean Difference (IV, Fixed, 95% CI)	‐0.26 [‐0.94, 0.41]

Comparison 14. Shock wave therapy (ESWT) versus ultrasound guided hyaluronic acid (HA) injection

Comparison 15. Radial extracorporeal shock wave therapy (rESWT) plus physiotherapy versus physiotherapy

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Mean pain Show forest plot	1	80	Mean Difference (IV, Fixed, 95% CI)	‐1.20 [‐1.58, ‐0.82]

2 Mean function Show forest plot	1	80	Mean Difference (IV, Fixed, 95% CI)	‐11.30 [‐14.75, ‐7.85]

3 Range of movement (ROM) flexion Show forest plot	1	80	Mean Difference (IV, Fixed, 95% CI)	31.60 [24.04, 39.16]

4 ROM extension Show forest plot	1	80	Mean Difference (IV, Fixed, 95% CI)	17.00 [14.10, 19.90]

5 ROM abduction Show forest plot	1	80	Mean Difference (IV, Fixed, 95% CI)	41.8 [32.79, 50.81]

6 ROM external rotation Show forest plot	1	80	Mean Difference (IV, Fixed, 95% CI)	23.2 [16.98, 29.42]

Comparison 15. Radial extracorporeal shock wave therapy (rESWT) plus physiotherapy versus physiotherapy