SummaryTreatment of degenerative joint disease (osteoarthritis) is discussed in relationship to pathogenesis of five clinical entities, defined to facilitate discussion:‐ 1) occurring in high motion joints and associated with synovitis; 2) associated with low motion joints; 3) “non‐progressive” articular cartilage erosion; 4) secondary to other identified problems (intra‐articular fractures, ligamentous damage, wounds, septic arthritis, osteochondrosis); and 5) chondromalacia of the patella. In addition to direct damage to articular cartilage, synovitis and capsulitis and depletion of matrical glycosaminoglycans and proteoglycans play important roles. The natural healing response in damaged articular cartilage is inadequate. The principles of treatment are divided into: 1) prevention or treatment of primary causes. These include the effects of track surface, shoeing, and the appropriate resolution of intra‐articular fractures, septic arthritis and osteochondritis dissecans. 2) treatment of active soft tissue disease contributing to articular cartilage degeneration, including rest, physical therapy, synovectomy and administration of anti‐inflammatory drugs, sodium hyaluronate and polysulfated glycosaminoglycans. 3) attempts at treatment of articular cartilage loss or degeneration, including articular cartilage curettage, subchondral bone drilling, osteophyte removal, articular cartilage grafting an