Osteoarthritis and Cartilage (1999) 7, 334–335  1999 OsteoArthritis Research Society International 1063–4584/99/030334+02 $12.00/0 Article No. joca.1998.0187, available online at http://www.idealibrary.com on

Osteophytes in osteoarthritis. Clinical aspects BY KENNETH D. BRANDT Professor of Medicine and Head, Rheumatology Division, Indiana University School of Medicine; Director, Indiana University Multipurpose Arthritis and Musculoskeletal Diseases Center

OSTEOPHYTES, both central and marginal, are an matic, although they usually do not result in integral pathologic feature of osteoarthritis OA. marked functional impairment and represent They are the single radiographic feature on which chiefly a cosmetic nuisance. Osteophytes may the diagnosis of OA may be established, according cause joint pain either by stretching nerve endings to criteria of the American College of Rheuma- in the periosteum or as a result of microfracture of tology [1] and the radiographic abnormality most the fragile bony trabeculae within the spur. In the strongly associated with knee pain [2], whereas apophyseal joints of the spine they may compress joint space narrowing is the most sensitive marker nerves, causing motor and/or sensory impairment. of OA progression. The Kellgren & Lawrence In addition, they may compromise cervical blood grading system for radiographic severity of flow, in which case they may cause, e.g., dizziness OA, which is weighted heavily toward osteophyto- or loss of vision. Anterior osteophytes in the cervical spine, which are due to spondylosis and sis, correlates poorly, however—as does joint not to osteoarthritis, may produce esophageal space narrowing in the conventional standing impingement and dysphagia. extended view radiograph of the knee—with the On the other hand, it has been suggested that severity of articular cartilage damage as seen marginal osteophytes play a protective role in arthroscopically [3]. stabilizing the OA joint, by putting tension on Although formation of new subchondral bone is collateral ligaments. Intra-operative removal of coupled to resorption of existing bone at that site, osteophytes from osteoarthritic knees has been osteophyte formation at the margins of the OA shown to increase varus and valgus instability [7]. joint occurs by the process of enchondral ossifica- For this reason, some investigators have cautioned tion. Therefore, antiresorptive drugs, which e#ec- that removal of osteophytes will accelerate articu- tively inhibit formation of cancellous subchondral lar cartilage degeneration in the osteoarthritic bone, have no e#ect on formation of marginal knee. Solid evidence that this is the case, however, osteophytes. Furthermore, in animal models, is lacking. Indeed, cheilectomy (the surgical disease-modifying drugs for OA (DMOADs), such removal of osteophytes) can improve mobility at as doxycycline, which can prevent the develop- the first metatarsophalangeal joint of patients ment of articular cartilage damage, may have with hallux rigidus without increasing either no e#ect on osteophyte formation [4]. On the symptoms or joint breakdown [8]. other hand, glucocorticoid administration, which has an anti-anabolic e#ect on connective tissue, may inhibit both cartilage breakdown and References osteophytosis [5]. It has been suggested that when osteophytes 1. Altman R, Asch E, Bloch D, Bole G, Brandt K, appear in the absence of other bony changes, e.g., Chrisey W et al. Development of criteria for the classification and reporting of osteoarthritis: subchondral cysts or subchondral sclerosis, they classification of osteoarthritis of the knee. may be a manifestation of aging, rather than of Arthritis Rheum 1986;29:1039–49. osteoarthritis, insofar as they often do not predict 2. Spector TD, Hart DJ, Byrne J et al. Definition of radiographic progression of joint damage over the osteoarthritis of the knee for epidemiological ensuing years [6]. In most cases, osteophytes are studies. Ann Rheum Dis 1993;52:790–4. 3. Brandt KD, Fife FS, Braunstein EM, Katz B. Radio- asymptomatic. However, they may be of clinical graphic grading of the severity of knee osteo- importance. In the interphalangeal joints of the arthritis: Relation of the Kellgren and Lawrence hand, osteophytes may be intermittently sympto- grade to a grade based on joint space narrowing,

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and correlation with arthroscopic evidence of 6. Danielsson L, Hernborg J. Clinical and roentgeno- articular cartilage degeneration. Arthritis Rheum logical study of knee joints with osteophytes. Clin 1991;34:1381–6. Orthop 1970;69:302–12. 4. Yu LP, Smith GN Jr, Brandt KD, Myers SL, 7. Pottenger LA, Phillips FM, Draganich LF. The O’Connor BL, Brandt DA. Reduction of the e#ect of marginal osteophytes on reduction of severity of canine osteoarthritis by prophylactic varus-valgus instability in osteoarthritic knees. treatment with oral doxycycline. Arthritis Rheum Arthritis Rheum 1990;33:853–8. 1992;35:1150–9. 8. Mann RA, Clanton TO. Hallux rigidus: treatment by 5. Pelletier J-P, Martel-Pelletier J. Protective e#ects of cheilectomy. J Bone Joint Surg 1988;30:400–6. corticosteroids on cartilage lesions and osteophyte formation in the Pond-Nuki dog model of osteoar- thritis. Arthritis Rheum 1989;32:181–93.