Abstract
We encountered a juvenile case of unstable shoulder presenting distinct “locking”-type symptoms. A 13-year-old girl had the chief complaint of pain in the right shoulder joint and a restricted range of motion. From age 12 years, the patient perceived instability of the right shoulder with no particular cause. Right shoulder pain and sense of luxation occurred during softball throwing. Physical findings demonstrated distinct restrictions for range of motion and end-feel in the final range of motion. Magnetic resonance arthrography （MRA） images demonstrated only a slight anterosuperior injury to the glenoid lip. Mobility training was pursued, but symptoms did not improve. Two months after the injury, surgical treatment was selected. Intraoperative arthroscopic findings showed minor damage to the anterior glenoid lip. Though the damage to the glenoid lip was slight, translation of the humeral head and irritation of the glenoid lip at this site was deemed the cause of the locking symptoms; the glenoid lip was repaired by the insertion of anchors. In the postoperative progress, the range of motion improved gradually, and at final observation （4 years）, the locking symptoms and pain had disappeared.
We hypothesize that the external force of the ball-throwing activity on the glenohumeral joint manifesting joint laxity and compromised shoulder girdle function caused a sense of luxation, with subsequent injury of the glenoid lip. Though the injury was slight, we believe that repair of the glenoid lip was an effective treatment modality in this case of unstable shoulder in a young individual presenting pain and “locking”-type symptoms.
