[Autologous chondrocyte transplantation--from science fiction to routine clinical practice]

Adult articular cartilage lacks the capacity for self-repair. The limiting factor appears to be the inability of chondrocytes to proliferate while embedded in the extracellular matrix typical of hyaline cartilage. Cartilage defects larger than 1 cm2 change articular biomechanics and lead to eventual osteoarthritis and joint destruction. During the past decade, several competing techniques have evolved to stimulate articular cartilage repair. Small lesions can be successfully treated by either micro-fracture or osteochondral cylinder grafting. The latter technique allows immediate weight bearing but leads to damage of previously uninvolved areas of articular cartilage, which limits its application to lesions of less than 2 cm2. When the damaged area is more extensive, grafting of autologous chondrocytes should be considered. First a diagnostic arthroscopy is performed to assess the damaged area and a small cartilage biopsy is taken. 6 weeks later, arthrotomy and chondrocyte transplantation are performed. In the interval, the antologous chondrocytes have expanded by 2 to 3 orders of magnitude. Our experience to date includes 10 cases with follow-up of 6 months to 5 years. Preoperative complaints of crepitation and locking disappear. There is functional improvement and pain reduction of approximately 50%. This procedure, currently limited to patients under 55 years of age with limited damage to an articular surface, for the first time allows reconstruction of damaged articular areas without resorting to allografts.