MR imaging of chondral and osteochondral injuries of the knee

Articular cartilage provides a nearly frictionless joint surface that is strong and resilient, able to tolerate both high-compressive loads and shearing stresses [I]. Joint replacements can improve symptoms caused by articular cartilage damage; however, they cannot completely reproduce the function of the native joint and they have a limited life span. Maintaining articular cartilage function is a critical goal in the treatment of joint disease. Damage to articular cartilage can occur because of inflammatory arthritis or noninflammatory causes, most commonly osteoarthritis and trauma. This article is limited to noninflammatory causes of articular damage. Osteoarthritis is the most common cause of articular cartilage damage, occurring in almost 75% of people over the age of 75 [2]. Damage to articular cartilage is also common in younger patients, with articular cartilage damage found in over 60% of patients undergoing arthroscopy [3,4]. Interest in improved imaging techniques for detecting articular cartilage damage has increased with the development of new treatments including osteochondral. transplant and autologous chondrocyte transplant. MRI can detect articular cartilage damage along with determination of its site, depth, and extent, which allows selection of patients for articular cartilage therapies.