There are few reports in the literature detailing arthroscopic treatment of unidirectional posterior shoulder instability.

Arthroscopic capsulolabral reconstruction is effective in restoring stability and function and alleviating pain in athletes with symptomatic unidirectional posterior instability. This population has significant differences in glenoid and chondrolabral versions when compared with controls.

Cohort study; Level of evidence, 2.

Ninety-one athletes (100 shoulders) with unidirectional recurrent posterior shoulder instability were treated with an arthroscopic posterior capsulolabral reconstruction and evaluated at a mean of 27 months postoperatively. A subset of 51 shoulders in contact athletes were compared with the entire group of 100 shoulders. Patients were evaluated prospectively with the American Shoulder and Elbow Surgeons scoring system. Stability, strength, and range of motion were evaluated preoperatively and postoperatively with standardized subjective scales. Forty-eight shoulders had magnetic resonance arthrograms performed and were available for review. The posterior inferior chondrolabral and bony glenoid versions were measured and compared with controls.

At a mean of 27 months postoperatively, the mean American Shoulder and Elbow Surgeons score improved from 50.36 to 85.66 (P < .001). There were significant improvements in stability, pain, and function based on standardized subjective scales (P < .001). The contact athletes did not demonstrate any significant differences when compared with the entire cohort for any outcome measure. The results in the 71 shoulders followed for at least 2 years were similar to the overall group. On magnetic resonance arthrography, the shoulders with posterior instability were found to have significantly greater chondrolabral and osseous retroversion in comparison with controls (P < .001 and P = .008, respectively).

Arthroscopic capsulolabral reconstruction is an effective, reliable treatment for symptomatic unidirectional recurrent posterior glenohumeral instability in an athletic population. Overall, 89% of patients were able to return to sport, with 67% of patients able to return to the same level postoperatively.