Arthroscopic Treatment of the Arthritic Shoulder

Nicholas D. Iagulli

Larry D. Field

Felix H. Savoie III

INDICATIONS/CONTRAINDICATIONS

Arthroscopic techniques have enabled surgeons to accurately diagnose and stage shoulder arthritis. Degenerative arthritis of the glenohumeral joint affects 20% of the elderly population, although it occurs less frequently than similar arthritis in weight-bearing joints of the lower extremity. Several authors have reported beneficial effects of arthroscopic treatment of the arthritic shoulder (1, 2, 3, 4).

Glenohumeral arthritis can be thought of as primary or secondary. Primary involvement occurs when no predisposing factor is identified. The structure and function of the shoulder may predispose it to degenerative wear as significant pressure and stresses are placed across the glenohumeral articulation with movement of the upper extremity. As the humeral head serves as a fulcrum to upper limb motion, pressures equal to ten times the weight of the extremity are transmitted across the articular surfaces of the joint. Any additional load or resistance placed on the extremity increases this pressure in an exponential fashion. Secondary involvement is more common and occurs as a result of an antecedent event that may include trauma, instability, chronic rotator cuff tear, and previous surgery. Primary arthritis may begin as early as the second decade and is more common in the elderly. Secondary arthritis, however, is more likely to affect younger more active patients.

Regardless of the etiology, initial treatment should be directed at resolution of symptoms and improvement of function. Mainstays of nonoperative treatment remain physical therapy, oral nonsteroidal anti-inflammatory agents, and the judicious use of corticosteroid injections. Additionally, injection of a synthetic hyaluronate (although not yet approved by the Food and Drug Administration) may prove beneficial. For patients with advanced degenerative changes who fail nonoperative management, joint replacement arthroplasty may provide satisfactory pain relief and return to function. In younger, active patients with less extensive arthritic disease, replacement arthroplasty is not a good option. This is due to the potential for limited lifespan of the prosthesis, as well as the activity restrictions placed on the patient who has undergone total shoulder arthroplasty. Arthroscopy is an accepted, viable treatment option for these patients (1, 3).

Patients appropriate for arthroscopic débridement include those with stages I to III arthritis who have a functional deficit or intolerable pain despite appropriate nonoperative management. Recently, evidence has shown that those with stage IV arthritis may also have substantial benefit from arthroscopic treatment (4). It should be emphasized to patients that the goal of treatment is primarily pain relief and that any functional gain is an added benefit. Additionally, many patients with primary osteoarthritis may have additional pathology in the shoulder. Labral tears, biceps pathology, partial or complete rotator cuff tears, subacromial spurs, and acromioclavicular (AC) arthritis may exist concomitantly. Arthroscopic management of these additional sources of discomfort may be helpful.

The mechanisms by which arthroscopy alleviates pain in arthritic joints are multifactorial. The benefit of lavage of arthritic joints dates to the first half of the 20th century. While the exact reason for this benefit is poorly understood, it likely results from the removal of degradative enzymes that are produced as part of the inflammatory process. Removal of inflamed synovium is also likely to reduce pain. Removal of mechanical irritants to the joint such as loose bodies, osteophytes, and chondral flaps improves function and relieves pain. Contouring of articular defects promotes kinematics of the joint that are more normal, thereby reducing inflammation
and enhancing function. Addressing coexisting problems such as rotator cuff tears, biceps pathology, capsular contracture, instability, AC arthritis, and impingement is possible and beneficial at the time of arthroscopy.

Full-thickness cartilage defects involving the humeral head, glenoid, or both can be incidental findings during shoulder arthroscopy. These chondral defects may be localized or more widespread and are often associated without clear radiographic findings of glenohumeral arthritis. Arthroscopic débridement, with or without abrasion chondroplasty or microfracture, seems to be a viable way to treat these localized grade IV lesions. This is similar in concept to abrasion chondroplasty for localized chondral defects in other joints. The long-term effect of abrasion chondroplasty on the shoulder is unknown.

The primary contraindication to arthroscopic management is the posteriorly subluxated shoulder. Walch et al. (5) have reported dissatisfactory results in these patients. Our results have been similar, and we do not routinely recommend arthroscopic débridement for this group. Although no other specific contraindications to arthroscopic treatment of the arthritic shoulder exist, more advanced glenohumeral arthritis, presence of large osteophytes, deformity of the humeral head, collapse of the humeral head, or significant bone deficits are unlikely to be helped with arthroscopic treatment alone. In addition, if a shoulder exhibits significant joint-space narrowing associated with capsular contracture, often found in end-stage glenohumeral arthritis, the actual establishment of arthroscopic portals may be difficult. Arthritis associated with large deficits in the rotator cuff, arthritis associated with significant rheumatoid arthropathy and soft-tissue deficits, and arthritis resulting from fracture and its concomitant deformity are unlikely to be adequately addressed with arthroscopic approaches and soft-tissue releases. More aggressive treatment of the shoulder is recommended in these situations. Finally, unrealistic expectations by the patient are probably a relative contraindication to the arthroscopic approach to glenohumeral arthritis. Patients should expect that limited goals of pain relief for a variable period are anticipated with arthroscopic débridement alone for glenohumeral arthritis.

PREOPERATIVE PLANNING

The typical patient who is a candidate for arthroscopic treatment of glenohumeral arthritis is a relatively young patient who presents with progressive pain in the shoulder with activity and at rest. Nonoperative management has frequently failed, including nonsteroidal anti-inflammatory medications, rehabilitation efforts, activity modification, and intra-articular injections. The ideal patient is one in whom intra-articular lidocaine has temporarily relieved the pain, reinforcing for the surgeon and patient that the source of pain is intra-articular as opposed to other areas around the shoulder. The pain in glenohumeral arthritis is characteristically located in the top lateral aspect of the arm and radiates down toward the deltoid insertion with any range of motion of the shoulder. Pain may be present with activities and at rest and frequently is described by the patient as a “toothache”-type of pain. Patients may also note symptoms of clicking, grinding, or catching due to loose cartilage flaps, joint incongruity, and intra-articular loose bodies. A patient will often give a history that the shoulder “goes out.” In the presence of glenohumeral arthritis, this is typically not instability but represents an incongruity in the humeral head sliding over areas of denuded glenoid articular cartilage.

History and Physical

As with all patient interactions, a thorough history and physical examination are the initial steps. Age, activity level, hand dominance, and comorbid illnesses should be reviewed. Those patients who are not candidates for general or regional anesthesia should be excluded. Previous injury and surgical history should be ascertained. Patient expectations should be discussed, and any unrealistic expectations should be discouraged.

Specific attention should be directed toward eliciting the source of discomfort. Many sources of shoulder pain can mimic the pain from glenohumeral arthritis. These sources include adhesive capsulitis (frozen shoulder), rotator cuff tears, biceps pathology, subacromial impingement, AC joint arthritis, synovitis, and even nonshoulder etiologies (cervical spine radiculopathy, Pancoast tumor, etc.). The best chance for symptomatic improvement of shoulder pain from glenohumeral arthritis is to specifically identify the glenohumeral joint as the sole source of the shoulder pain. In many instances, differential injection of Xylocaine (AstraZeneca, Wilmington, DE) may aide the surgeon in identifying the precise source of pain, whether subacromial, AC joint, or glenohumeral joint.

Examination should include the observation for asymmetry between affected and unaffected sides. Atrophy, swelling, surgical incisions, deformity, subdeltoid or subcutaneous cysts, and any other areas of asymmetry are identified. The carrying posture of the extremity should also be noted. Range of motion of the involved extremity should be obtained and compared to the opposite extremity. The examiner should note in which planes arc of motion is diminished. It is important to remember that arthropathies are commonly bilateral. The motions typically tested are forward flexion, external rotation with the arm at the side, and external/internal rotation with the arm abducted to 90 degrees. In patients with early glenohumeral arthritis, external rotation is frequently diminished. As the disease progresses, the loss of forward flexion and internal rotation are noted. Shoulder range of motion produces crepitation, pain, and abnormalities of scapulothoracic rhythm. Although physical exam testing of strength and instability is routine, it may be painful for the patient. Internal and external rotation strength is
predominantly determined by competence and function of the rotator cuff. In many types of arthropathy, such as periosteoarthritis of the shoulder, avascular necrosis, and postcapsulorrhaphy arthropathy, it is typical to have normal internal and external rotation strength. However, contraction of the rotator cuff may center the humeral head on the glenoid and may be responsible for the deep crepitus, grating, and grinding that frequently occurs in active motion and strength testing in glenohumeral arthritis. Any questions about integrity of neurovascular structures should be investigated further. If there is a discrepancy between passive and active range of motion, this is due to involuntary limitation of active motion due to pain, muscle atrophy, neurogenic deficit, or rotator cuff incongruity.

Specific examination techniques can help pinpoint the source of shoulder discomfort. Reproduction of symptoms by minimal glenohumeral glide testing signifies the arthritic glenohumeral joint as the source of pain. Loading the humeral head into the glenoid and then shifting it in different directions should produce crepitation and reproduce the patient’s pain if glenohumeral arthritis is the main factor producing symptoms. Crepitation or pain at the more extreme load and shift displacement may signify labral pathology in addition to arthritis.

Palpation for swelling and areas of proximal tenderness is also beneficial. Manual testing for impingement, biceps pathology, and AC arthritis may elicit those areas as additional sources of pain, signifying potential improvement with arthroscopic management.

Multiple sources of shoulder pain do not preclude successful treatment arthroscopically. For example, early glenohumeral arthritis may coexist with subacromial impingement syndrome, AC joint arthritis, or painful contracture of the shoulder joint. Multiple etiologies of the shoulder pain may be addressed at the time of arthroscopy, such as combining arthroscopic subacromial decompression with débridement for mild glenohumeral joint arthritis. Differential injections prior to surgery can be helpful in identifying the predominant source of shoulder pain.

Radiographic assessment begins with plain radiographs. Three views are routinely obtained: an anteroposterior view of the glenohumeral joint, a scapular Y view, and an axillary lateral view. These views allow adequate assessment of the glenohumeral joint, including joint-space narrowing, subchondral sclerosis, subluxation, and osteophyte formation. AC degeneration and hypertrophy can be assessed. Acromial morphology can be determined as well. Additional findings may include chondrocalcinosis or signs of associated pathology such as a Hill-Sachs lesion or narrowed subacromial interval.

Nakagawa et al. (6) and Weinstein et al. (1) have proposed staging of glenohumeral arthritis based on radiographic findings. Stage I arthritis has normal-appearing radiographs and is found only at the time of arthroscopy. Stages II through IV are evident radiographically (Fig. 8-1). Stage II is characterized by minimal joint-space narrowing and a concentrically located humeral head in the glenoid. Stage III exhibits moderate joint-space narrowing and inferior osteophyte formation. Stage IV changes include severe loss of joint space, osteophyte formation, and loss of concentricity between the humeral head and glenoid.

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