Background: Prior evidence has identified specific posterior acromial morphology as significantly associated with unidirectional posterior shoulder instability. The purpose of this study is to determine the influence of posterior acromial morphology on the outcomes of arthroscopic posterior capsulolabral repair (APCLR) for unidirectional posterior shoulder instability. Additionally, we sought to determine the influence of posterior acromial morphology on the rate and time to return to pushups following APCLR.
Methods: We performed a retrospective review of prospectively collected data. The study included consecutive patients undergoing APCLR. Data collected included demographics, radiographic measurements including posterior acromial height (PAH) and posterior acromial tilt on preoperative scapular-Y radiographs, and patient-reported outcome measures at the preoperative and postoperative visits. In addition, starting at 6 months postoperative, patients were asked if they could perform pushups defined as at least 10 repetitions. At the final follow-up, we collected the number of pushups patients were able to perform.
Results: Thirty-two consecutive patients underwent APCLR with a mean follow-up of 26 months (range, 12-41). Significant improvement from preoperative to 2 years postoperative was demonstrated in Subjective Shoulder Value (50-85), VAS (6-2.5), American Shoulder and Elbow Surgeons (48 to 83), and Western Ontario Shoulder Instability (WOSI) (1437-777), P = .001. The recurrent instability rate was 3/32 (9%). Patients with PAH > 23 (N = 17) had a recurrent instability rate of 18% (3/17) versus PAH ≤ 23 (N = 15) 0% (0/15), worse WOSI scores (P = .41), and a lower number of pushups (P = .48). The percentage of patients reporting the ability to perform pushups was (6 months/1 year/2 years) (50%/78%/95%). The mean number of pushups reported at the final follow-up was 33 (range, 1-60).
Discussion: Following APCLR, approximately 50% of patients resume pushups at 6 months postoperatively, and 80% return at 1 year. Patients reported performing a mean of 33 pushups following APCLR at the final follow-up. Patients with a PAH greater than 23 on preoperative scapular-Y radiographs had a higher rate of recurrent posterior instability, worse WOSI scores, and lower return to pushups; however, the results did not meet statistical significance. Therefore, future larger studies are needed to determine if posterior acromial morphology is independently associated with worse outcomes and increased recurrent instability rates following APCLR.
Keywords: Arthroscopy; Capsulolabral; Posterior acromial height; Posterior labral repair; Posterior labrum tear; Pushups; Shoulder surgery.