Glenohumeral Osteoarthritis in Active Patients
Diagnostic Tips and Complete Management Options
Ariane Gerber, MD; Janne T. Lehtinen, MD; Jon J. P. Warner, MD
THE PHYSICIAN AND SPORTSMEDICINE - VOL 31 - NO. 4 - APRIL 2003
In Brief: In the normal glenohumeral joint, the humeral head and the glenoid articulate via smooth and congruent articular surfaces. In the osteoarthritic shoulder, however, both the articular surface anatomy and orientation may be severely distorted and the soft tissues grossly contracted, leading to pain and loss of function. While replacement arthroplasty is the treatment of choice in the elderly, therapeutic options for young active patients include conservative treatment, arthroplasty, and corrective osteotomy and are directed, whenever possible, toward joint preservation.
Although degenerative articular changes may affect the shoulder joint with an incidence equal to that of hip and knee arthritis, only 5% to 10% of patients with shoulder pain manifest degenerative joint disease.1 These may include posttraumatic arthritis, rheumatoid arthritis, inflammatory arthritis, and arthritis after surgery for instability. The incidence of shoulder osteoarthritis appears to increase with age,2 and the typical patient having degenerative shoulder joint changes is in the sixth or seventh decade of life. As with other joints, different primary and secondary forms of degenerative arthritis have been described in the shoulder, and many different etiologic factors can be responsible for degenerative articular changes (table 1).
Arthritis in the young patient is most likely to develop following trauma, shoulder surgery, or an inflammatory joint condition. Shoulder involvement occurs in 25% of patients who have juvenile rheumatoid arthritis, and it usually occurs in the polyarticular form. This is a disabling condition for young individuals who may develop rapid and aggressive destruction of the shoulder joint and are therefore rarely very physically active. Thus, our approach for these patients is to perform shoulder arthroplasty before severe destruction occurs, so that joint architecture will allow reconstruction. This approach takes preference over the patient's age. While inflammatory arthropathy of the shoulder presents a difficult challenge, we will focus on the more common conditions of degenerative, posttraumatic, and postsurgical arthritis, which may affect older as well as younger patients.
Epidemiology and Pathogenesis
Degenerative changes in the young patient usually arise from trauma or as a consequence of surgery for instability. Degenerative arthritis is a possible complication after traumatic glenohumeral dislocation. In a 10-year prospective study3 assessing the outcome of primary glenohumeral dislocation treated with closed reduction, the incidence of degenerative changes on conventional x-rays was 20% (11% with mild degenerative changes and 9% with severe joint alteration). This study also showed that degenerative arthropathy can develop after a single dislocation and is not more frequent if recurrent instability occurs. Another study demonstrated a 5% incidence of previously unrecognized osteochondral lesions in 1,500 shoulder arthroscopies performed in young patients.4 This supports the hypothesis that initial articular trauma may play an important role in the development of osteoarthritis.5,6
The senior author (J.J.P.W.) has observed a number of patients younger than 40 who had a symptomatic posterior subluxation of the humeral head after an injury without dislocation.7 All patients manifested a posterior osteochondral lesion of the glenoid. The pathogenetic mechanism leading to osteoarthritis in these patients remains unclear; however, our hypothesis would be that osteoarthritis arose from increased compressive forces on the posterior edge of the joint caused by fixed subluxation of the humeral head.
Chronic locked (anterior or posterior) dislocations can also lead to degenerative changes of the glenohumeral joint. It is interesting to note that almost two thirds of posterior dislocations are not recognized7,8 and, therefore, not treated adequately. The major pathologic mechanism in patients who have an unrecognized disorder is a massive loss of articular surface of the humeral head and softening of the glenoid cartilage stemming from disturbance of circulation and load.
Degenerative articular changes are a common feature of malunion of comminuted and displaced fractures of the proximal humerus (three-part and four-part fractures in the Neer classification).9 Malunion of the articular fragment in relation to the greater tuberosity leads to disruption of the glenohumeral biomechanics.10 Therapeutic options in these situations are limited, and clinical results are disappointing. Posttraumatic avascular necrosis (AVN) is another complication that can occur after proximal humeral fracture. The incidence is not well defined, but the highest rate of AVN has been observed after three- and four-part fractures.11 Open reduction and internal fixation with large implants exacerbates this risk.11 In the absence of malunion, AVN is usually well tolerated.12 If AVN occurs in the setting of a malunited three- or four-part fracture, poor function will result, regardless of secondary corrective procedures. Therefore, surgical treatment to achieve anatomical reduction using minimal invasive surgical techniques is almost always indicated and is usually possible in younger patients with good bone quality who have comminuted proximal humeral fractures.
Neer13 recognized that a frequent cause of arthritis in the younger patient is "a standard operative procedure intended to remedy recurrent unidirectional dislocations that is inappropriately performed on a loose multidirectional shoulder. The procedures displace the humeral head in a loose shoulder away from the side of the repair, creating a fixed subluxation. The subluxed head wears unevenly on the glenoid, and arthritic changes can develop surprisingly fast." Studies of biomechanics have indeed demonstrated that tightening of a portion of the capsule can cause excessive translation of the humeral head during glenohumeral rotation and unbalanced loading of the joint.14 Termed "capsulorrhaphic arthropathy," this condition can lead to osteoarthritis with severe posterior segmental glenoid erosion and humeral head subluxation.
Symptoms. A patient's symptoms can vary, depending on the severity of the articular lesion. The leading complaint is gradual and progressive onset of pain, located "deep" in the joint, typically on the posterior side of the shoulder. When joint involvement is moderate, pain occurs with active range of motion, especially under loaded conditions (eg, in sports and heavy work). As degenerative changes become more advanced, pain occurs at rest and becomes constant. Typically, the patient also notices marked loss of range of motion. Posttraumatic conditions with malunion of the proximal humerus are always associated with a severe loss of function (figure 1).
Examination. In the early stages of osteoarthritis, physical examination can be unremarkable, with normal range of motion and normal rotator cuff function. Depending on the location of the degenerative changes, pain can be induced by placing the arm in a provocation position. The patient with a posterior glenoid lesion and posterior subluxation typically experiences pain when the arm is in forward flexion and internal rotation without complaining about instability (apprehension). Patients with advanced stages of AVN may report painful locking of the shoulder and subsequent "giving way." This sensation can usually be reproduced during the physical examination and is the sign of a loose body in the joint or a partially detached osteoarticular humeral fragment.
In more advanced stages, loss of active and passive range of motion occurs—loss of external rotation and forward flexion is typical. In patients with capsulorrhaphic arthropathy, loss of external rotation can be severe, and symptoms of instability can still be present. In patients who have had previous surgery or trauma, careful physical examination should exclude concomitant rotator cuff pathology (subscapularis tendon) and nerve lesions.
Radiographs. Glenohumeral osteoarthritis can usually be diagnosed using conventional x-rays.4 The severity of articular cartilage degeneration may not be visible on a single routine anteroposterior (AP) view. Optimal imaging of the joint space requires a true AP view taken with the x-ray beam oriented obliquely 30° toward the frontal plane. Furthermore, an axillary view should always be part of a conventional radiographic evaluation. Joint-space narrowing can be visualized more reliably on this view and dislocation excluded. An AP radiograph with the arm actively held at 45° of abduction can sometimes reveal joint-space narrowing when neutral AP x-rays are normal.7 This becomes apparent because muscle contraction produces active compression of the joint surfaces. Osteophyte formation, subchondral bone irregularities, and glenoid bone loss may also be seen on regular films. Localized degenerative changes in the early stages can be difficult to assess on regular x-rays.
Other techniques. A computed tomography (CT) arthrogram can be of great value to localize pathologic joint changes precisely. Furthermore, glenoid deformities can be accurately determined only with a three-dimensional study such as CT.15 If soft-tissue pathologies are suspected, magnetic resonance imaging (MRI) or MRI arthrogram is the method of choice. Complete pain relief after an intra-articular injection of lidocaine hydrochloride indicates that the corresponding structural lesion is most likely localized in the glenohumeral joint. Occasionally, arthroscopy is useful as a diagnostic tool to determine the extent of glenohumeral arthritis, assess concomitant pathology such as labral lesions, and debride the joint.7,16
In early stages, painful stiffness can mimic adhesive capsulitis; however, adhesive capsulitis usually leads to a rapid loss of range of motion, and imaging studies fail to demonstrate degenerative joint changes. After trauma, painful loss of external rotation can be the consequence of posterior dislocation (figure 2). This condition can be excluded with an axillary view radiograph of the shoulder. The first onset of an inflammatory joint disease can be characterized by pain and stiffness. Pain at night and warm and swollen joint(s) are typical findings and serve to distinguish the condition from osteoarthritis.
Treatment of early shoulder osteoarthritis should always begin with conservative management. Physical therapy plays an important role in improving motion, increasing stability, and strengthening the shoulder.17 Passive and active range-of-motion exercises are used to stretch the capsular tissue sleeve and to gain functional range of motion. Any capsular tightness should be corrected by stretching before strengthening exercises begin.18 When muscle imbalance is present, strengthening of weak muscle groups (most often external rotators) is recommended. Modification in sports activity and work tasks has been proposed,19 but this is often not a viable option for young adults.
Pain medication is usually added to a physical therapy program, but it is not a long-term solution in young patients. Nonsteroidal anti-inflammatory drugs (NSAIDs) are traditionally used because of their analgesic and anti-inflammatory effects.17 Because of their lower rate of side effects, cyclooxygenase-2 (COX-2) inhibitors are an appealing alternative to NSAIDs. Cortisone injection of the glenohumeral joint has been proved effective in treating pain and is recommended, especially if an inflammatory component is present.17
In young, active patients, expected results of joint-preserving surgical options for shoulder arthritis focus on reducing pain and mechanical symptoms, increasing range of motion, and avoiding prosthetic replacement.7
Arthroscopic procedures. Arthroscopic debridement includes removal of ulcerated, irregular cartilage and tapering of the margins. All degenerative labral tissue is removed, and degenerative tissue on both surfaces of the rotator cuff is debrided. Any inflamed reactive synovial and bursal tissue is also removed.7
In a review of 54 patients with osteoarthritis of the shoulder with a 3-year follow-up, Ogilvie-Harris and D'Angelo20 found that in patients with mild degenerative findings, successful arthroscopic outcome occurred in two-thirds. In those with severe degeneration, a successful outcome was realized in only one third of the cases. Factors associated with a favorable outcome included the removal of osteoarthritis debris and degenerative glenoid labrum tissue.
Ellman et al21 reported that in 18 patients with impingement and coexisting osteoarthritis, arthroscopic debridement produced significant improvement in pain with a follow-up of 6 months to 3 years. Weinstein et al16 noted that in a series of 25 patients with early degenerative arthritis, 80% who underwent debridement had satisfactory pain relief; average follow-up was 34 months. Satisfactory results were also seen in case reports.22
Based on studies such as these, it appears that patients with concentric articulations and minimal preoperative loss of motion benefit most from this surgery. However, the long-term effectiveness of this procedure in early osteoarthritis requires further study.
In patients with moderate anterior capsular contracture and slight posterior subluxation of the humeral head, combined capsular release and debridement have also demonstrated good results.5 Recently, a short-term review23 of 14 patients with asymmetric wear of the glenoid who were treated with arthroscopic glenoidplasty revealed a significant decrease in pain; 79% of patients had a high degree of satisfaction.
Capsular release. In capsulorrhaphic arthropathy, anterior capsular release has been shown to improve motion and decrease the abnormal compressive forces on the joint surfaces, thus improving pain and possibly retarding the degenerative process.5 Both open and arthroscopic release are effective. Among patients in the early stages of the degenerative process, good results were achieved when only mild posterior translation of the humerus was seen in axillary view x-rays.7
Interpositional arthroplasty. This technique is designed primarily to treat rheumatoid shoulders and is performed by attaching a capsular flap or fascia lata transplant to the eroded glenoid surface.24 For most active patients with degenerative or posttraumatic glenohumeral arthritis, interpositional arthroplasty is not an alternative to prosthetic arthroplasty, because the results are usually less favorable and can be unpredictable.7 However, the combination of hemiarthroplasty and biologic resurfacing of the glenoid as an alternative to total-shoulder replacement has provided good results in younger patients.25
Corrective osteotomies. Open-wedge osteotomies of the glenoid (figure 3) have been done to treat patients with symptomatic fixed posterior subluxation and posterior glenoid wear, and the technique can represent an option in selected cases.7,26 If posterior subluxation and only mild posterior glenoid wear are present, and external rotation is not limited, a posterior-capsular-shift procedure can serve as an alternative treatment.
Joint-Replacing and Resecting Procedures
Patients who have severe joint damage may require more intensive therapies.
Replacement arthroplasty. Shoulder arthroplasty for degenerative, posttraumatic, postcapsulorrhaphy, or inflammatory arthritis provides the most successful and predictable relief of pain, and it results in the best functional outcome compared with interposition arthroplasty or arthrodesis.7 For active patients, and usually for young patients, the benefits of prosthetic arthroplasty must be tempered with concerns for potential problems associated with aseptic loosening of the components, particularly the glenoid component. Glenoid loosening is the most frequent complication following total shoulder replacement.27 After 10 to 15 years of follow-up, revision surgery for symptomatic glenoid loosening has been estimated at 5% to 10%.27 Therefore, for young, active patients in whom joint-preserving procedures are no longer indicated, hemiarthroplasty may be a logical alternative to total shoulder replacement. As previously noted, hemiarthroplasty can be combined with biological resurfacing of the glenoid, especially in shoulders that have mild, uniform glenoid involvement. However, studies have clearly established that, with advanced osteoarthritis, outcomes for pain and function measures are significantly better with total shoulder replacement than with hemiarthroplasty.28 This is especially true in shoulders that have eccentric wear patterns.5
Arthrodesis and resection arthroplasty. Indications for arthrodesis for patients who have degenerative arthritis have become rare, but arthrodesis can be an option for end-stage unilateral shoulder arthritis in patients who have strenuous physical demands, such as heavy manual labor. Problems that arise after multiple failed surgeries or with symptomatic recurrent voluntary shoulder dislocation can usually be addressed with this technique only. Resection arthroplasty has been advocated previously, but it is now considered solely as a salvage procedure.
Options for the Future
The degree of degenerative changes and patient functional demands determine the most appropriate treatment plan. Conservative measures play an important role as the initial therapy for most patients. Theoretically, modification of activities could serve as an important adjunct in managing shoulder arthritis in active patients, but acceptance is relatively low in this group. In the early stages of the arthritic process, once conservative treatment has failed, joint-preserving procedures represent clinically efficient alternatives to joint replacement. In more advanced cases, joint replacement is often the only acceptable solution (figure 4).
New prosthetic design that respects the patient's anatomy and the use of new materials may improve long-term results of replacement arthroplasty and constitute an earlier solution for young, active patients. Finally, in the future, new technologies such as cartilage transplantation, genetically engineered cartilage, and control of the inflammatory or degenerative processes via genetic modification in cells may play a role.
Dr Gerber and Dr Lehtinen are fellows and Dr Warner is chief, all in the Harvard Shoulder Service at Massachusetts General Hospital in Boston. Address correspondence to Jon J. P. Warner, MD, 275 Cambridge St, Box 403, Boston, MA 02114; e-mail to [email protected].
Disclosure information: Drs Gerber and Lehtinen disclose no significant relationship with any manufacturer of any commercial product mentioned in this article. Dr Warner receives royalties from prostheses manufactured by Centerpulse. No drug is mentioned in this article for an unlabeled use.