Osteonecrosis of Humeral Head after Arthroscopic Capsular Release for Postoperative Shoulder Joint Stiffness: A Case Report

An arthroscopic capsular release (ACR) is used for persistent shoulder stiffness after an index surgery. No cases of post-ACR humeral head osteonecrosis have been reported to date. A 56-year-old male patient underwent open reduction and internal fixation using a hook plate for acromioclavicular joint dislocation. Despite hardware removal, the patient presented with unresolved shoulder pain and range-of-motion (ROM) limitations. He had a history of hypertension, chronic hepatitis B infection, and alcohol consumption. His preoperative ROM was 90 degrees for active forward flexion, 90 degrees for abduction, 40 degrees for external rotation, and at a sacral level for internal rotation. His preoperative functional status was a visual analog scale (VAS) score of 4, an American Shoulder and Elbow Surgeons (ASES) score of 51, and a Constant-Murley (CMS) score of 48 through normal radiography and magnetic resonance imaging. A standard ACR was performed with a 360 degrees release of the joint capsule via electrocautery ablation. Six months post-ACR, his ROM (forward flexion: 135 degrees; abduction: 135 degrees; external rotation: 70 degrees; internal rotation: T10 vertebra) and functional outcomes (VAS 2; ASES 79; CMS 75) were significantly improved, without an interval change in radiographic assessment. However, 15 months post-operation, the patient experienced a recurrence of shoulder pain and subsequently underwent triamcinolone injections in both the 15th and 21st postoperative months. Radiography revealed humeral head osteonecrosis. Patients with intrinsic or extrinsic risk factors related to humeral head circulation disturbance should be monitored for humeral head osteonecrosis post-ACR.