Elsevier

The Journal of Arthroplasty

Volume 30, Issue 9, September 2015, Pages 1555-1560
The Journal of Arthroplasty

What is the Fate of Total Hip Arthroplasty (THA) Acetabular Component Orientation When Evaluated in the Standing Position?

https://doi.org/10.1016/j.arth.2015.03.025Get rights and content

Abstract

This retrospective study measured the change of the acetabular component orientation between supine and standing radiographs in 113 THA patients and identified the associated anatomical parameters that may help direct pre-operative planning. The mean change of the acetabular component inclination and version from supine to standing was 4.6° and 5.9° respectively (P < 0.0001), with 49 (43%) hips showing inclination change > 5° and 69 (53%) hips showing version change > 5°. Twelve (43%) of 28 ‘malpositioned’ cups became ‘well-positioned’ and 26 (31%) of 85 ‘well-positioned’ cups became ‘malpositioned’ upon standing. Changes in inclination were associated with leg length discrepancy and pelvic obliquity; and changes in version were associated with pelvic tilt and pelvic incidence. Standing position and patient factors should be considered when defining “optimal” acetabular orientation.

Section snippets

Methods

The authors’ hospital database was utilized to identify all total hip arthroplasty patients who had undergone standing radiographic evaluation at 3–6 months follow-up during the study period of June 2012 through December 2012. There were 113 patients who had obtained both supine and standing radiographic imaging on the same day and these patients were included in the study. The imaging was performed as part of the acquisition of an EOS system and initial testing. The selection of patients was

Supine vs. Standing Acetabular Component Orientation

There were statistically significant differences in supine (40.6°; range 22.6°–67.6°) versus standing (43.3°; range 19°–17°) inclination (P < 0.0001) as well as supine (12.8°; range 0.9°–33°) versus standing (17.6°; range 4.5°–37.3°) version (P < 0.0001). The mean change, by absolute value, of the acetabular component inclination and version from supine to standing was 4.6° (0.01°–16.2°) and 5.9° (0–17.2), respectively. With respect to inclination, 49 (43%) hips had a change > 5°, and 7 (6%) hips

Discussion

Acetabular component orientation has an important impact on clinical outcomes following THA 1., 2., 3., 4., 5., yet achieving satisfactory position remains one of the challenges of this overall highly successful procedure [6]. Adverse outcomes including, but not limited to, instability and wear are often associated with malpositioning, but these complications are also observed in hips with well-positioned acetabular components. Additionally, good outcomes are not uncommonly observed in hips

Acknowledgement

The authors would like to thank Selami Cakmak, MD and Dov Goldvasser, MS for their technical assistance with the radiographic data analysis.

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    One or more of the authors of this paper have disclosed potential or pertinent conflicts of interest, which may include receipt of payment, either direct or indirect, institutional support, or association with an entity in the biomedical field which may be perceived to have potential conflict of interest with this work. For full disclosure statements refer to http://dx.doi.org/10.1016/j.arth.2015.03.025.

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