What Are the Indications for Conservative Treatment Versus Core Decompression Versus Arthroplasty in Avascular Necrosis of the Humeral Head?
After the femoral head, the humeral head is the second most common site of osteonecrosis or avascular necrosis (AVN) (Figure 23-1). Unfortunately, once the blood supply to an involved area of the humeral head is compromised and bone death occurs, there is no reversal. Progressive AVN leads to eventual subchondral collapse and glenohumeral arthritis. Hence the appropriate management of humeral head AVN involves early suspicion and diagnosis in an attempt to preserve the shoulder joint.1
Figure 23-1. Anteroposterior radiograph demonstrating AVN of the humeral head with subchondral collapse.
AVN is classically “staged” by the Cruess modification of the Arlet-Ficat classification system (Table 23-1). Clinical and radiographic evaluation of humeral head AVN allows for an individualized approach to management.1 We closely evaluate range of motion (ROM) in comparison to the opposite (usually uninvolved) shoulder. In each patient with suspected AVN, our standard plain radiographic views (anteroposterior views in neutral and external rotation, axillary-lateral view, and supraspinatus outlet view) are combined with magnetic resonance imaging (MRI) in order to evaluate the extent of the necrosis. In addition to nonoperative measures such as nonsteroidal anti-inflammatory drugs (NSAIDs) and physical therapy, operative treatment for AVN involves either reduction in intraosseous pressure (core decompression), replacement of the diseased head (hemiarthroplasty), or replacement of the entire joint (total shoulder arthroplasty).
For early stage disease prior to subchondral collapse (stages 0, 1, and 2), joint preservation techniques remain paramount. Although a short trial (6-week increments) of simple nonoperative exercises and activity modification may be initiated, we consider these early stages as the shoulder “at risk,” and hence utilize aggressive nonoperative treatment in conjunction with arthroscopic modifications of the core decompression procedure as soon as possible.2 Peer-reviewed literature has demonstrated successful clinical and radiographic evidence supporting the use of core decompression in retarding the progression of AVN in these early precollapse stages. We combine clinical history with MRI to confirm this diagnosis and proceed with management. Patients are counseled that although core decompression indeed reduces pain, the long-term results beyond 5 to 10 years remain unknown (Figure 23-2). We perform this procedure in the upright beach-chair position, under both arthroscopic and fluoroscopic control. A standard anterior cruciate ligament tibial targeting guide is utilized through a standard anterior glenohumeral arthroscopic portal in order to confirm appropriate placement under the softened and sometimes fibrillated area of cartilage (most commonly in the anterosuperolateral humeral head). Under fluoroscopic imaging, a guide pin is placed through a small incision on the lateral arm and advanced to the subchondral surface—confirming lack of articular penetration via the arthroscope in the joint. This pin is over-reamed with a standard 6- or 7-mm acorn reamer depending on patient size, taking care not to advance the pin into the joint. Aggressive postoperative management includes no immobilization, immediate terminal ROM and stretching exercises, scapular stabilization strengthening, and emphasis on glenohumeral and scapulothoracic flexibilities.
Figure 23-2. Anteroposterior radiograph 5 years after arthroscopic assisted core decompression. Humeral head architecture is still preserved.
When the subchondral plate has collapsed (stage 3 and beyond), we do not recognize the benefit of joint preservation surgery. These patients are managed with a more prolonged course of conservative management (3-month increments) with heavy emphasis on glenohumeral flexibility and activity modification. Some patients will respond to these measures and may be satisfied with their shoulders, although disease progression remains inevitable. For these “early responders,” we recommend follow-up at 3- to 6-month intervals in order to continue measures to alleviate symptoms (judicious use of corticosteroid injections, alterations in the NSAID regimen, etc).
If all nonoperative attempts are exhausted due to persistent disabling symptoms, we proceed to arthroplasty as our operative management (Figure 23-3). The decision for hemiarthroplasty versus total shoulder arthroplasty must be carefully considered based on 3 parameters: (1) stage of the disease and the joint collapse, (2) status of the soft-tissue contractures associated with this disease, and (3) age of the patient.3
Figure 23-3. Hemiarthroplasty for AVN.
1. Wolfe CJ, Taylor-Butler KL. Avascular necrosis. Arch Fam Med. 2000;9:291-294.
2. Chapman C, Mattern C, Levine WN. Arthroscopically assisted core decompression of the proximal humerus for avascular necrosis. Arthroscopy. 2004;20:1003-1006.
3. Mansat P, Huser L, Mansat M, et al. Shoulder arthroplasty for atraumatic avascular necrosis of the humeral head: nineteen shoulders followed up for a mean of seven years. J Shoulder Elbow Surg. 2005;14:114-120.