Reconstruction of Humeral Head Defect for Locked Posterior Shoulder Dislocation

Abstract

Locked posterior shoulder dislocation is a rare injury and is often missed on examination, usually due to inadequate imaging and potentially resulting in significant loss of shoulder function. An important feature of the physical examination is identification of the patient's inability to externally rotate their arm. These injuries are associated with defects in the humeral head articular surface, also known as reverse Hill-Sachs lesions. Medium-sized defects involving 25% to 50% of the articular surface can be reconstructed using several methods, including subscapularis or lesser tuberosity transfer, rotational osteotomy of the humerus, osteochondral autografting, and allograft reconstruction. We describe reconstruction of a 40% anteromedial humeral head articular surface defect associated with a missed locked posterior shoulder dislocation. Our technique used a deltopectoral approach with soft tissue dissection through the rotator interval to enable direct access to the defect with preservation of the rotator cuff muscles. The impacted articular surface was elevated, and the void was filled with moldable putty consisting of tricalcium phosphate with carboxymethylcellulose (Calstrux; Stryker Biotech, Hopkinton, Massachusetts). The articular fragment was then secured in position with size 5 Ethibond (Ethicon, Inc, Somerville, New Jersey) bone sutures. The patient regained excellent function and range of motion, with computed tomography scanning at 9 months demonstrating a smooth humeral articular surface with excellent graft incorporation. This technique avoids donor site morbidity and potential risks with allograft use while maintaining normal shoulder joint anatomy with preservation of the rotator cuff muscles for less complicated prosthetic reconstruction if required in the future.