Unconstrained Shoulder Arthroplasty for Treatment of Proximal Humeral Nonunions: Surgical Technique.

Abstract

Anatomic unconstrained arthroplasty for the treatment of proximal humeral nonunion is challenging and may require management of rotator cuff tearing or scarring, glenohumeral instability, shoulder capsule fibrosis, poor bone quality and bone defects, and glenohumeral arthritis and may require internal fixation and bone-grafting for stimulation of healing. Obtain anteroposterior, axillary, and lateral scapular Y views of the shoulder to assess the fracture for the size and position of the humeral head, humeral shaft, and greater and lesser tuberosities as well as for fracture nonunion. In cases with substantial contracture or difficult exposure, use an anteromedial approach. For three and four-part fractures, secure the tuberosity fragments with strong sutures and then mobilize them from the articular fragment and the humeral shaft. The tuberosity bone fragment should be reduced to the prosthesis with positioning 6 to 10 mm below the top of the humeral head component. Fixation of the humeral stem usually requires cement, but avoid cement in the area of the tuberosity nonunion to help prevent necrosis of the bone resulting in further nonunion. To achieve tuberosity healing in anatomic alignment, reduce the tuberosities anatomically followed by bone-grafting and rigid fixation. Patients use a shoulder immobilizer for six weeks, begin formal physical therapy at two to four weeks, and initiate a shoulder strengthening program at about ten to twelve weeks. The management of proximal humeral nonunion is challenging and historically results have shown reasonable pain relief with limitations in function. IndicationsContraindicationsPitfalls & Challenges.