Functional recovery after a reverse prosthesis for reconstruction of the proximal humerus in tumor surgery.

UNLABELLED: An alternative treatment for primary bone tumors of the proximal humerus was assessed. Four patients, who made full functional recovery after complete resection of the proximal humerus inclusive of the rotator cuff and subsequent reconstruction with a reverse shoulder prosthesis, were examined clinically and radiographically. Distinct medialization of the center of rotation of the glenohumeral joint (28 mm) and elongation of the remaining deltoid muscle (116%) were measured. Increased scapular rotation (118%) was observed. The radiologic results and thoracoscapular rhythm analyses were implemented in a three-dimensional computerized model of the glenohumeral joint. This allowed us to calculate a doubling of the moment of the deltoid abductor muscle in the true scapular plane. After tumor surgery, in which the proximal humerus is resected without reinserting the rotator cuff, full functional recovery of the shoulder can be obtained with a total shoulder prosthesis, medializing the glenohumeral center of rotation and elongating the remaining deltoid muscle. LEVEL OF EVIDENCE: Therapeutic study, Level IV (case series-no, or historical control group).