Posterior Capsular Rupture Causing Posterior Shoulder Instability: A Case Report

We report the case of a 20-year-old male competitive football player who was treated for a midsubstance posterior capsule rupture after a posterior dislocation from falling onto his shoulder. Conservative management for 5 months after the injury failed to improve his subjective symptoms, with the primary symptom being activity-related posterior shoulder pain. Advanced imaging findings and physical examination were consistent with posterior instability, thought to be due to a posterior labral tear. At the time of a diagnostic arthroscopy, the patient was found to have an oval-shaped rupture of the capsule that was neither a reverse humeral avulsion of the glenohumeral ligament lesion nor a posterior labral tear. The capsular tear was repaired through an all-arthroscopic technique with nonabsorbable sutures. The patient returned to his previous competitive function, had no pain, and had full motion at final follow-up without recurrence of instability or pain symptoms.