Shoulder Osteonecrosis Treatment & Management

Treatment of humeral head osteonecrosis varies, depending on the stage and symptoms. Eliminating the inciting factor if and when it is recognized is an important initial step, but does not reverse the course of the disease process. Treatment often can be delayed or is not required because the shoulder is a non–weightbearing joint. However, in the face of severe pain and/or mechanical symptoms, conservative and surgical options are available. No specific contraindications to treatment exist, other than those pertaining to high surgical risk situations. Infection or severe systemic disease may preclude surgical intervention.

Removal of the offending agent, if possible, is the first line of treatment. Nonsurgical options often are more successful in cases of shoulder osteonecrosis than in hip osteonecrosis because the shoulder is a non–weight-bearing joint. Physical therapy that include modalities for pain control and range of motion (ROM) exercises with subsequent strengthening is helpful in all stages, but 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.

In core decompression, a central core of bone is removed or drilled from the humeral head into the necrotic zone. ^[11]  Studies of core decompression have shown good and excellent results in up to 90% of cases of stage I and stage II disease. ^{[12, 13]} 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. ^[11]  An alternative technique of decompression utilizing multiple passes of a small-diameter (3-mm) drill in a percutaneous fashion has been described. ^[14]

A prospective randomized clinical study of 50 patients with post-traumatic shoulder osteonecrosis compared the results of mesenchymal stem cell grafting of the humeral head versus simple core decompression alone. After more than a decade of follow-up, the rate of collapse was significantly lower in the group treated with stem cells (11.55 vs 87.5%, P < 0.0001). ^[15]

Limited experience with muscle pedicle grafting has shown no significant difference from core decompression alone, with increased morbidity. Further studies are required. ^[16]  Arthroscopic debridement of chondral lesions may be performed. Arthroscopy has no effect on the disease process, but it may be helpful in dealing with mechanical symptoms. 

Depending on the condition of the glenoid, hemiarthroplasty (HA) (see image below) or total shoulder arthroplasty (TSA) can be considered. ^{[17, 18, 19]} A 90% success rate has been reported for hemiarthroplasty and total shoulder arthroplasty in advanced-stage disease, with most patients regaining full ROM. ^{[17, 19]} Surface replacement arthroplasty is also an option. ^{[20, 21]}

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. In patients with atraumatic osteonecrosis of the humeral head, both hemiarthroplasty and total shoulder arthroplasty can be expected to provide lasting pain relief and improved range of motion, but hemiarthroplasty has had longer follow-up. Schoch and colleagues recommend that hemiarthroplasty be strongly considered in patients with atraumatic osteonecrosis of the humeral head and preserved glenoid cartilage. ^[22]

In a comparision of 37 HAs and 46 TSAs performed for post-traumatic osteonecrosis of the humeral head after conservative treatments failed, HA provided improvements in range of motion but TSA provided superior pain relief with better patient-reported satisfaction. ^[23]  

 Intraoperative details vary according to the procedure chosen.

Core decompression is performed as follows:

• Place the patient in the beach-chair position with the arm over the edge of the table
• Use 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.

If the drilling technique is utilized, the operative setup is identical, but instead of using a coring reamer, multiple passes are made into the lesion with a small-diameter drill (usually 3.2 mm) under image intensification.

Arthroscopy can be combined with decompression allowing for an intrarticular debridement. Articular cartilage flaps can be debrided back to a stable rim, loose bodies removed, and a selective capsular release can be performed as needed.

Hemiarthroplasty involves placement of a humeral head prosthesis, usually through a deltopectoral iapproach. For idiopathic osteonecrosis, the procedure is technically easier to perform than hemiarthroplasty for advanced arthritis, as the patient usually has 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.

For 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.

In surface replacement arthroplasty, the humeral head only is resurfaced partially or completely with a metal component.

In patients who have undergone 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.

In patients who have undergone 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.

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.

Potential complications with arthroplasty include prosthetic loosening, dislocation, and intraoperative fracture. Fortunately, these problems are rare in avascular necrosis.