Cartilage substitutes: overview of basic science and treatment options.

Articular cartilage defects that are symptomatic and refractory to nonoperative treatment represent a clinical management challenge. Although there have been important advances in stimulating intrinsic repair mechanisms, cartilage regeneration, and other substitution techniques, to date none has unlocked the understanding necessary to duplicate normal articular cartilage. The objectives of treatment of cartilage lesions are to obtain pain relief, reduce effusions and inflammation, restore function, reduce disability, and postpone or alleviate the need for prosthetic replacement. As the field of articular cartilage repair continues to evolve rapidly, the most appropriate treatment option for an individual patient should be based on the pathologic characteristics of the lesion and the patient's symptoms and expectations. The orthopaedic surgeon needs to be familiar with both the existing and the newly emerging cartilage treatment techniques in order to best educate patients and meet their expectations for long-term benefits.