The evidence for surgical repair of articular cartilage in the knee.

The complex structure and biomechanical function of articular cartilage make chondral injuries a management challenge. Articular cartilage has limited, if any, capacity to heal and/or regenerate. Although the natural history of articular cartilage lesions has not been clearly studied, significant injuries are believed to progress, resulting in degenerative arthritis of the joint. Changes have been made in surgical techniques in an attempt to better manage these lesions, and a large industry has been built around arthroscopic and open surgical procedures for managing cartilage repair. However, there is limited evidence that any intervention significantly alters the natural history of these lesions. Randomized trials have been done to examine the outcomes of common restoration procedures performed in the United States today, such as microfracture, osteochondral autograft transfer, and autologous chondrocyte implantation. Because the natural history of articular cartilage lesions has not been defined, we can assess the utility of surgical interventions only by comparing methods.