Disruption of the posterior-lateral shoulder capsule.

The occurrence of lateral capsular disruption as a cause of anterior shoulder instability has been reported previously. 1 It was suggested that this injury be considered in patients with instability and no injury or a minimal injury to the glenoid labrum. We now report the occurrence of lateral capsular disruption of the posterior aspect of the shoulder as a cause of pain and weakness. This Lesion can be difficult to diagnose with roentgenography and is difficult to assess with arthroscopy unless anterior portals are used for visualization. CASE REPORT A 2]-year-old, right-handed, professional hockey player presented with left shoulder pain beginning 6 months before evaluation. He reported being driven into the boards by opposing players and being hit from behind and in front with his left arm at his side at the moment of impact. He had immediate diffuse shoulder pain with any movement and a sense of shoulder weakness but no sense of instability. The pain worsened with exercise and prevented him from continuing to play. The pain was fairly constant and present at night. It was poorly localized to the superior part of the shoulder, and the pain increased with forward shoulder flexion. Figure 1 Arthroscopic view of posterior gienohumeral joint demonstrating lateral capsule rupture near humeral head. Patient is in beach chair position, and rupture is visualized via anterior portal. On office examination the patient had no evidence of atrophy or deformity of the left upper extremity or the neck. He had a negative cervical spine examination and was neurologically intact. On range-of-motion testing he was found to have symmetric abduction and forward flexion with pain at the extremes of motion on the left. His internal rotation was five vertebral segments less on the left shoulder than on the right shoulder, and his external rotation was symmetric at 80 ~. He had a negative sulcus sign 4 bilaterally. No anterior laxity was seen on the left or right shoulder. With a posteriorly directed stress, a palpable posterior shoulder click that was painful to the patient was felt on the left side. The patient had 1+ posterior laxity ~ on the left shoulder compared with no laxity on the right shoulder.