Shoulder Osteonecrosis Treatment & Management

Removal of the offending agent, if possible, is the first line of treatment. Nonsurgical options often are more successful in cases of shoulder osteonecrosis because the shoulder is a non–weightbearing joint. Physical therapy that include modalities for pain control and ROM exercises with subsequent strengthening is helpful in all stages, particularly in stage I and stage II.

Studies have shown that treatment with alendronate can possibly prevent a collapse of the femoral head caused by osteonecrosis; however, no research has been published regarding its effectiveness in treating osteonecrosis of the shoulder.

• Core decompression: A central core of bone is removed or drilled from the humeral head into the necrotic zone.^[7]
• Arthroscopy: Arthroscopic debridement of chondral lesions is performed.
• Hemiarthroplasty: Humeral head prosthetic replacement is performed (see image below).^{[8, 9, 10]} Shoulder hemiarthroplasty in a patient with shoulder osteonecrosis.
• Total shoulder arthroplasty: The humeral head is replaced with glenoid resurfacing.^{[8, 10]}
• Surface replacement arthroplasty^{[11, 12]}

The decision for a given surgical procedure is based on preoperative staging. Core decompression, muscle pedicle grafting, and arthroscopy are indicated in cases prior to collapse of the humeral head. These procedures can be helpful in stage I, stage II, and stage III disease. Once irregularity of the joint surface occurs, arthroplasty is most beneficial.

• Core decompression: Place the patient in the beach-chair position with the arm over the edge of the table. Perform core decompression with the use of image intensification. Make a small incision in the lateral deltoid. Place a Kirschner wire (K-wire) into the necrotic lesion, and use a cannulated drill to take a core of bone.
• Hemiarthroplasty: Place a humeral head prosthesis, usually through a long deltopectoral incision. For idiopathic osteonecrosis, the procedure is technically easier to perform than hemiarthroplasty for advanced arthritis, as there is usually minimal-to-no soft-tissue contracture and head deformity. By using the excised head as a sizer, near-perfect replacement of the articular surface can be achieved.
• Total shoulder arthroplasty: Multiple prostheses are available. The glenoid is resurfaced, usually with an all-polyethylene component. Total shoulder arthroplasty is indicated in individuals with stage IV disease.
• Surface replacement arthroplasty: The humeral head only is resurfaced partially or completely with a metal component.

• Core decompression and muscle pedicle grafting: Immediate ROM exercises can be initiated. Some limitations on ROM may be placed in cases of muscle pedicle grafting. Patients with core decompression are started on immediate passive ROM exercises, with active ROM as tolerated. Once full ROM is achieved, strengthening exercises can be initiated.
• Hemiarthroplasty and shoulder arthroplasty: Immediate passive ROM is initiated, with limitation of external rotation to 45° for 6 weeks to allow for repair of the subscapularis from the surgical approach. Active ROM can be started as tolerated, with the same limitation in the absence of rotator cuff repair, which is rare. Strengthening usually is initiated at 6 weeks postsurgery.

• Core decompression: Studies of core decompression have shown good and excellent results in up to 90% of cases of stage I and stage II disease.^{[13, 14]} Core decompression also can be successful in stage III disease, with a 30% failure rate requiring subsequent arthroplasty. Failure occurs in all cases of stage IV or V disease; the procedure is palliative only.^[7]
• Muscle pedicle grafting: Limited experience with this procedure has shown no significant difference from core decompression alone, with increased morbidity. Further studies are required.^[15]
• Arthroscopy: Limited studies are available for review. Arthroscopy has no effect on the disease process, but it may be helpful in dealing with mechanical symptoms.
• Arthroplasty: A 90% success rate has been reported in advanced-stage disease, with most patients regaining full ROM.^{[8, 10]}

Common surgical complications include infection and neurovascular injuries, which are particularly rare in these procedures.

When performing core decompression, care must be taken to avoid the axillary nerve anteriorly. Avoidance of penetration of the humeral head during core decompression is key.

The cephalic vein is at risk during the approach for arthroplasty. Problems with arthroplasty include prosthetic loosening, dislocation, and intraoperative fracture. Fortunately, these problems are rare in avascular necrosis.

The shoulder joint bears less weight than the joints of the lower extremity; therefore, symptoms can be mild, even in those with advanced disease. Many patients obtain good results when conservatively treated with analgesics and/or physical therapy for extended periods of time. Surgery can be reserved for those with severe pain, as patients with early-stage disease often do not progress radiographically.

Disease prevention is the key. Identifying those at risk and defining preventive measures is helpful. Fortunately, many cases can be treated successfully without surgical intervention. Prosthetic fixation in those with osteonecrosis of the shoulder often can be performed without cement because of good bone quality. Clinical identification of disease progression is critical to recognize and treat symptomatic disease in the early stages, thereby avoiding arthroplasty.