Conservative management of the osteoarthritic knee

Abstract

Osteoarthritis (OA) is the most common type of arthritis affecting synovial joints. Recent advances have altered the traditional progression of medical therapy for OA and have supplied new alternatives for the treatment of refractory OA. The new selective cyclooxygenase-2–inhibitory nonsteroidal anti-inflammatory drugs, celecoxib and rofecoxib, have significantly improved safety profiles, particularly with respect to serious gastrointestinal side effects and platelet inhibition. They should be used preferentially in higher-risk patients. Intra-articular viscosupplementation of the knee with exogenous hyaluronic acid has been approved by the US Food and Drug Administration as a medical device for the treatment of OA of the knee. It is reportedly as effective as nonsteroidal anti-inflammatory drugs for moderate OA of the knee. Finally, arthroscopic knee-joint lavage, with or without steroids, is another alternative for the treatment of knee OA; it should be considered before surgery is contemplated. Agents that may prevent cartilage degradation, such as the nutraceuticals (glucosamine sulfate, chondroitin sulfate, and collagen hydrolysate) or inhibitors of nitric oxide or metalloproteinases, may prove beneficial but are still under investigation. Abbreviations:COX cyclooxygenase, HA hyaluronic acid, NSAID nonsteroidal anti-inflammatory drug, OA osteoarthritis In the United States, osteoarthritis (OA) is the most common type of arthritis affecting synovial joints and the most prevalent form of arthritis [1,2]. The exact pathogenic mechanisms of OA have not been clearly elucidated, but OA has traditionally been considered a disease of cartilage. Certain subsets of OA evolve primarily from defective cartilage, and recent studies suggest that the surrounding tissues, including the subchondral bone, the synovium, and the periarticular muscles and ligaments not only are pathologically altered by OA but also may contribute to the primary abnormality. There is no known cure for OA, but the search for new treatments continues because OA is associated with significant morbidity and progressive disability. Since the Guidelines for the Medical Management of OA were published in 1995, several scientific advances have been made and two new therapies have been approved by the US Food and Drug Administration. Exogenous hyaluronic acid (HA) (ie, viscosupplementation) for intra-articular administration in the knee was approved in 1998 as a medical device. Currently, two formulations of HA—sodium hyaluronate (Hyalgan, Sanofi Winthrop, Padua, Italy) and Hylan G-F 20 (Synvisc, Wyeth-Ayerst, Ridgefield, NJ)—are used specifically for the symptomatic relief of OA of the knee. In 1999, two new members of the nonsteroidal anti-inflammatory drug (NSAID) family, the selective cyclooxygenase-2 (COX-2) inhibitors celecoxib (Celebrex) and rofecoxib (Vioxx, Searle Pharmaceuticals, Skokie, IL), were released for marketing in the United States. Because of these new therapeutic options, the Guidelines for the Medical Management of Knee OA [2] are being revised and should be submitted for publication after approval by the American College of Rheumatology (Hochberg M. Personal communication).