Abstract
Background:
While reverse shoulder arthroplasty (RSA) has shown successful outcomes for a variety of shoulder pathologies, postoperative scapula fractures continue to be one of the most common complications limiting outcomes with rates reported between 0.8–7.2%. Previous literature has shown that postoperative scapula fractures have a deleterious effect on elevation and outcomes scores, however these studies were all performed at short-term follow-up from the fracture. It has also not been shown whether postoperative scapular fractures increases risk of revision surgery. The purpose of this study was to determine the effect of postoperative scapula fracture on the outcomes following RSA at minimum 1 year follow-up from the fracture.
Methods:
A retrospective, case-control study of 25 nonoperatively treated postoperative scapula fractures following RSA in a single surgeon's practice was analyzed with minimum 2 year follow-up from surgery and 1 year follow-up from fracture. Patients with postoperative scapula fractures were matched 1: 4 to a control group for age, sex, total follow-up time, indication for surgery, and primary versus revision surgery. Outcome measures including revision surgery, ASES score, and change in range of motion were compared between fracture cases and controls. Radiographic features including fracture location (acromion vs. scapular spine) and healing of fracture was also analyzed with respect to outcome.
Results:
The incidence of postoperative scapula fracture following RSA in this series was 3.1% (32/1018). Fractures occurred from 1–94 months postoperatively, at an average of 16 months. Revision rate was higher in the fracture group (8%, 2/25) than in controls (2%, 2/100) but did not reach statistical significance (p = 0.18). Patients with fractures had inferior clinical outcomes with a postoperative ASES score of 58.0 compared to 74.2 in controls (p = 0.001), but were clinically improved from preoperative scores with an average improvement of 21 points. Improvement in range of motion was also decreased in the fracture group with a mean gain of forward elevation of 26° compared to 76° in controls (p < 0.001). Fracture location (acromion versus scapular spine) (p = 0.54) or healing (p = 0.40) did not affect outcome.
Conclusion:
Postoperative scapula fractures may occur at any point during the postoperative period therefore increasing incidence is likely as longer follow-up becomes available. This complication leads to inferior clinical results compared to controls, however patients show improvement compared to their preoperative measurements, even at longer term follow-up. Patients sustaining postoperative scapula fractures may have increased risk of revision surgery.
