Management of Cartilage Defects in the Shoulder
While much has been written regarding the treatment of chondral lesions in the knee,1 until recently glenohumeral articular cartilage lesions have remained a poorly understood and usually incidentally diagnosed entity. However, increased awareness, and the widespread use of magnetic resonance imaging and arthroscopy has allowed for a more conscientious and thorough evaluation of the articular surfaces which in turn has demonstrated that chondral defects in the shoulder are more common than previously thought. While the incidence of glenohumeral articular cartilage lesions in the general population is unknown, arthroscopies performed for other indications reveal an incidence rate of 6-17%. After an anterior instability event, these lesions are even more common at 23% of the glenoid side and 8% on the humeral side.
Numerous factors may incite a chondral lesion, including trauma, instability, previous surgical intervention with associated chondrolysis, osteonecrosis, rotator cuff arthropathy, septic arthritis, inflammatory arthritis, osteoarthritis, and osteochondritis dissecans. Chondral lesions are generally identified in association with other intra-articular glenohumeral pathology. For instance, the presence of a superior labral anterior-posterior tear increases the likelihood of identification of a chondral lesions from 4 to 20% on the humeral side and 5 to 18% on the glenoid side. In young patients, the glenohumeral pathology most commonly leading to the discovery of chondral lesion is instability. A dislocation event increases the risk of the development of glenohumeral osteoarthritis 10-20 times and the incidence of glenohumeral osteoarthritis is 10-20% in those that suffer an instability event at mid- to long-term follow-up.
While the natural history of these chondral lesions is largely unknown, they may progress to glenohumeral osteoarthritis. While rare glenohumeral osteoarthritis can have significant effects on a patient’s global function, with declines in health-related quality of life on-par with diabetes and coronary artery disease.
The factors that lead to progression are largely unknown and possibly different from those within the knee given that the glenohumeral joint is not a classic weight-bearing joint in the same sense that the lower extremity diarthrodial joints experience load. Shear stresses related to physiologic glenohumeral translation may contribute to progression. In comparison to the knee, the articular cartilage of the humeral head and glenoid fossa are thin at 1.24 and 1.88 mm thick respectively, which leaves less margin before exposure of the subchondral bone. It should be noted that this margin is even thinner at the periphery of the humeral head and at the center of the glenoid fossa. Systematic chondral degenerative changes related to age likely also contribute to progression, as do osseous lesions leading to articular incongruity. Finally, chondral defects of the glenohumeral joint are generally very well tolerated and often asymptomatic, thus it is incumbent upon the evaluating physician to properly determine and treat other more common sources of shoulder pain prior to embarking on cartilage-specific treatment.
Once a symptomatic chondral lesion has been identified, a trial of non-operative therapy is warranted, including ice, nonsteroidal anti-inflammatory medications, and physical therapy. Therapy with a focus on strengthening of the periscapular musculature and rotator cuff may be particularly effective to address any concomitant scapular dyskinesis. In addition, in overhead throwers stretching can be useful to address any glenohumeral internal rotation deficit that may be contributing to microinstability and may be placing abnormal stress upon the articular cartilage and therefore possibly contributing to progression. We also make use of intraarticular corticosteroid injections in patients with an inflammatory component to their discomfort. Hyaluronic acid injection may also be used, although its use in glenohumeral lesions remains off-label. The efficacy of nonoperative treatment protocols in the short and long-term in regards to symptomatic management and alteration of natural history remains to be determined.
In patients who have tried a comprehensive course of non-operative treatment with residual discomfort, operative treatment can be considered. A variety of operative treatment options exist for these lesions. These options can generally be classified into reparative, restorative, and salvage treatments. Reparative options include microfracture techniques. Restorative options include cellular-based techniques such as autologous chondrocyte implantation, osteochondral autograft transplantation, and osteochondral allograft transplantation. Salvage techniques include debridement techniques with or without capsular release, chondroplasty, and subacromial decompression; biological resurfacing techniques with meniscal allograft, anterior capsule, periosteum, or another biologic interposition material; and prosthetic resurfacing and arthroplasty techniques. While total shoulder arthroplasty generally provides excellent pain relief and function, the limited lifespan of prosthetic replacements limits application in younger patients and thus our review is limited to non-arthroplasty techniques.
Given the plethora of treatment options, the treating surgeon who encounters a chondral defect is left without clear guidelines of which option might provide their patient with the best outcome. While several reviews have been written, no inclusive, recent systematic reviews exist within the literature to provide the surgeon with evidence-based recommendations for treatment of these lesions. In addition, the majority of the evidence on the subject has been released within the past two years, which may make prior conclusions less pertinent today.
The objective of this study was to conduct a (1) systematic review of clinical outcomes following cartilage restorative and reparative procedures in the glenohumeral joint; (2) to identify patient specific prognostic factors that predict clinical outcome after cartilage surgery of the shoulder; (3) to provide treatment recommendations based on the best currently available evidence and to (4) highlight gaps in the literature that require future research.