Rehabilitation of articular lesions in the athlete's knee.

Articular cartilage lesions of the knee joint are common in patients of varying ages. Some articular cartilage lesions are focal lesions located on one aspect of the tibiofemoral or patellofemoral joint. Other lesions can be extremely large or involve multiple compartments of the knee joint and these are often referred to as osteoarthritis. There are numerous potential causes for the development of articular cartilage lesions: joint injury (trauma), biomechanics, genetics, activities, and biochemistry. Numerous factors also contribute to symptomatic episodes resulting from lesions to the articular cartilage: activities (sports and work), joint alignment, joint laxity, muscular weakness, genetics, dietary intake, and body mass index. Athletes appear to be more susceptible to developing articular cartilage lesions than other individuals. This is especially true with specific sports and subsequent to specific types of knee injuries. Injuries to the anterior cruciate ligament and/or menisci may increase the risk of developing an articular cartilage lesion. The treatment for an athletic patient with articular cartilage lesions is often difficult and met with limited success. In this article we will discuss several types of knee articular cartilage injuries such as focal lesions, advanced full-thickness lesions, and bone bruises. We will also discuss the risk factors for developing full-thickness articular cartilage lesions and osteoarthritis, and describe the clinical evaluation and nonoperative treatment strategies for these types of lesions in athletes.