Operative stabilization of posterior shoulder instability

Abstract

Background: Symptomatic, traumatic posterior shoulder instability is often the result of a posteriorly directed blow to an adducted, internally rotated, and forward-flexed upper extremity. Operative repair has been shown to provide favorable results. Current arthroscopic techniques with suture anchors and the ability to plicate the capsule using a nonabsorbable suture may provide favorable outcomes with reduced morbidity.

Purpose: To evaluate the results of operative shoulder stabilization in patients with traumatic posterior shoulder instability.

Study design: Case series; Level of evidence, 4.

Methods: A consecutive series of patients who underwent arthroscopic or open posterior stabilization for traumatic posterior shoulder instability were evaluated using subjective assessments, physical examinations, the Single Assessment Numeric Evaluation, Rowe score, Simple Shoulder Test, and the Western Ontario Shoulder Instability Index.

Results: Between May 1996 and February 2002, 31 shoulders (30 patients) underwent posterior stabilization (19 arthroscopically, 12 open). There were 29 men and 1 woman (mean age, 23 years). Preoperatively, all patients had a distinct traumatic cause for the instability. On physical examination, all patients had posterior apprehension and increased (2+, 3+) posterior load-shift testing. Preoperative radiographs and/or magnetic resonance imaging revealed posterior rim calcification or reverse Bankart lesions in 29 cases (94%). At arthroscopy, posterior labral injuries, reverse Bankart lesions, or humeral head defects were identified. Follow-up averaged 40 months, and the mean duration between injury and surgery was 21 months. The mean Single Assessment Numeric Evaluation, Rowe score, Simple Shoulder Test, and Western Ontario Shoulder Instability Index scores, respectively, for the entire group were 89, 87, 11, and 346; for the open group, they were 81, 80, 10.5, and 594; for the arthroscopic group, they were 92, 92, 11.4, and 190. The Western Ontario Shoulder Instability Index (P < .03) and Rowe score (P < .04) outcomes scores for the arthroscopic group were statistically better than those of the open group. Twenty-nine of 31 shoulders were rated as excellent or good.

Conclusion: In the case of traumatic posterior shoulder subluxation, posterior lesions of the labrum ("reverse Bankart"), articular edge, and capsule are observed. Surgical treatment addressing these lesions led to satisfactory results for both the open and arthroscopic treated groups. In this study, an arthroscopic technique utilizing suture anchor repair with capsular placation provided the most favorable outcomes.