Treatment of articular cartilage defects with the autologous chondrocyte transplantation (ACT).

Symptomatic chondral lesions in the knee remain a problem for young sportsmen and pose a difficult management issue for orthopedic surgeons and patients alike. Damaged articular cartilage has a limited potential for healing and can lead to premature arthritis. Articular defects larger than 2 mm to 4 mm in diameter rarely heal. Neither articular cartilage possesses a lymphatic drainage, a sufficient blood supply, nor neural elements. Also, they are sheltered even from immunological recognition, because of the extracellular matrix surrounding the chondrocyte.