Humeroscapular arthrodesis is a well-established operative procedure that involves fusion of the humeral head to the glenoid. In some procedures, the fusion also includes an acromiohumeral arthrodesis. Humeroscapular arthrodesis is commonly called shoulder arthrodesis. Indications for this procedure early in the 20th century included the treatment of residual glenohumeral destruction resulting from tuberculosis and the treatment of upper extremity paralysis resulting from poliomyelitis. Additional historical indications included osteoarthritis, rheumatoid arthritis, irreparable injury of the rotator cuff, and severely comminuted fracture of the proximal aspect of the humerus. However, the advent of shoulder arthroplasty has resulted in a marked reduction in the number of shoulder arthrodesis performed, although there are instances when arthrodesis is favored over joint replacement arthroplasty. Current indications for shoulder arthrodesis include posttraumatic brachial plexus injury, paralytic disorders in infancy, insufficiency of the deltoid muscle and rotator cuff, chronic infection, failed revision arthroplasty, severe refractory instability, and bone deficiency following resection of tumor in the proximal aspect of the humerus (1).

Shoulder arthrodesis is an extensive procedure. The techniques for shoulder arthrodesis include internal fixation and external fixation. Rigid internal fixation with either single-or double-plating is probably the most commonly used technique for obtaining a solid fusion. Several factors have contributed to a high rate of successful fusion. These include the combination of rigid internal fixation as well as incorporation of both intra-articular (glenohumeral) and extra-articular (acromiohumeral) surfaces (1).

Complications with shoulder arthrodesis can occur and can be potentially devastating. This chapter will cover the most common complications associated with shoulder arthrodesis. The complications include wound healing problems, wound infection, fractures below the level of the fusion, nonunion of the arthrodesis, and malposition of the arthrodesis (1,2). Surgical corrections for a malpositioned arthrodesis will also be addressed. Less common complications include acromioclavicular dislocation, acromioclavicular arthrosis, and suprascapular traction neuritis, which is primarily caused by excessive abduction and forward flexion of the fusion resulting in increased tension on the scapular muscles, acromioclavicular joint and suprascapular nerve (3, 4, 5, 6).

Many authors have stressed the value of internal fixation for maintenance of the position of the humeral and scapular surfaces, especially when the arthrodesis combines both intra-articular (glenohumeral) and extra-articular (acromiohumeral) techniques. This combination has resulted in
a high rate of successful fusion, although complications continue to be reported (1).

Difficulties that may arise with shoulder arthrodesis are not unique to this long and difficult operative procedure. Wound infection at the operative site is managed with standard techniques, which include irrigation and drainage along with culture of specimens from the wound. Appropriate antibiotics (an intravenous course followed by an oral course) have been successful in the treatment of this wound problem. In the early postoperative period, hardware retention should be attempted at all costs. Infection with a more virulent gram-positive organism may make this difficult. Infections that are recalcitrant to conservative measures may require hardware removal to help eradicate the infection. In an unstable patient or an elderly patient with low functional demands, conversion to a resectional arthroplasty should be considered. In other patients and those infected with more common gram-positive organisms, a delayed revision arthrodesis should be considered once successful union has been achieved. In the late postoperative period with clinical and radiographic evidence of healing, hardware removal should be considered to help eradicate the infection. In short, hardware contributing to harboring of organisms leading to tissue destruction warrants removal.

Wick et al. (7) reported the long-term results of arthrodesis of the shoulder after septic arthritis in 15 patients. They were able to show an increased rate of complications in patients with active sepsis. Younger patients (<50 years) and those with fewer previous operations (<4 operations) had better outcomes. The main complication was persistent infection with failure of bony fusion. Considering the rate of complications, they recommended early surgery in these patients. Similarly, a wound hematoma may develop, particularly in association with harvest of iliac-crest bone graft. Evacuation of the hematoma is often indicated. Also related to the harvest of iliac-crest bone graft are the risk of injury to the lateral femoral cutaneous nerve and the potential development of meralgia paresthetica (1).

Fracture about the shoulder may occur in a patient treated with a shoulder arthrodesis. The fracture may occur in association with the fixation device or distal to the site of the arthrodesis. Distal fractures have responded to nonoperative treatment with simple use of a coaptation splint. Union has been observed to occur without substantial change in the position of the shoulder. Fractures that occur more proximally in association with internal fixation devices have been successfully treated with removal of the devices and repeat plate application and bone-grafting (1). It is important to span the fusion site as well as the fracture site with an appropriately sized 4.5-mm pelvic reconstruction or a 4.5-mm dynamic compression plate. The use of synthetic auto- or allograft should be considered at the surgeon’s discretion.