Evaluation of screw placement in proximal humerus fractures regarding drilling manoeuvre and surgeon's experience

Highlights

• The aim was to determine the influence of surgeons’ experience and the technique of drilling on the complication rate.

• The perforation rate of the articular cavity ranged from 3.4% to 5.2%.

• There were no statistically significant differences regarding drilling manoeuvres nor experience.

Abstract

Introduction

Following proximal humeral plate osteosynthesis, mechanical complication rates ranging up to 40% have been reported. The study aims to determine the influence of surgeons’ experience and the technique of drilling on the complication rate.

Materials and Methods

The sample involved 45 cadaveric humeri. Six orthopaedic surgeons were divided into two groups with regard to their level of experience (novice versus expert group). On each humerus two different proximal humerus plates were applied. Drillings were performed either with a sharp or worn drill bit (to simulate either sharp or blunt drilling). The respective holes were drilled until the respective participant thought to have placed the drill bit subchondrally, followed by perforation of the cartilage of the humeral head. Both these values and cases of unintended penetration of the articular cavity were evaluated.

Results

Fourteen holes (3.6%) were primary penetrated in the joint cavity in the worn-drill-bit-subgroup and 19 holes (5%) in the sharp-drill-bit-group. The latter had an average distance between the chosen subchondral position and the humeral articular surface of 8.3 mm and the worn-drill-bit-subgroup was at 10.6 mm. In the novice group 20 perforations (5.2%) of the joint space occurred and the mean interval between the chosen subchondral point and the humeral articular surface was 4.0 mm. The experienced surgeons showed a perforation rate of 3.4% and were at a mean of 14.9 mm. There were no significant differences regarding drilling manoeuvres and experience.

Conclusion

Although our results are satisfactory, they can be traced back to the relatively high interval between the respective chosen position of the drill bit and the humeral articular surface which may not guarantee screw stability during ORIF of all fracture patterns.

Introduction

Proximal humerus fractures represent circa 5% of all fractures, with notable increase of incidence in elderly women [1]. Regarding young patients, they are mostly the result of high-energy traumas, whereas in the older population these fractures occur commonly due to osteoporotic bone constitutions.

The treatment of proximal humerus fractures has been a very moving subject and is still a controversial topic in orthopaedic and trauma surgery. Currently, the literature lacks scientific evidence for the best treatment option. Although most of these fractures are stable and can be treated conservatively [2], a large variety of techniques has been described for their surgical treatment [2], [3], [4], [5], [6]. Surgical intervention is recommended for displaced fractures and commonly involves open reduction and internal fixation (ORIF). Unfortunately, clinically relevant complications following this procedure have been described by several authors [7], [8], [9], [10]. In order to reduce these complication rates, an anatomically pre-shaped proximal humeral internal locking system (PHILOS, Synthes GmbH, Oberndorf, Switzerland) was developed to improve screw fixation in the osteoporotic bone and to minimize soft tissue damage. Stable screw fixation is especially necessary in the osteoporotic bone since osteoporotic fractures tend to be more complex with progress of the disease as postulated by Court-Brown et al. [11]. The PHILOS plate provides angular stability which is especially useful in osteoporotic bone [12] and recently published clinical studies show promising outcomes regarding their use [13,14]. Nevertheless, complication rates ranging up to 40%, including post-interventional dislocations as well as loss of reduction and screw perforations have been reported [15].

The aim of this study was to determine the efficacy of proximal humerus plating regarding screw length, over penetration of humeral head, surgeon's experience and different drill techniques in a cadaveric model.