Autologous chondrocyte transplantation for reconstruction of isolated joint defects: the Assaf Harofeh experience

Background: Articular cartilage is incapable of undergoing self-repair sinc e chondrocytes lose their mitotic ability as early as the first year of lif e. Defects in articular cartilage, especially in weight-bearing joints, wil l predictably deteriorate toward osteoarthritis. No method has been found t o prevent this deterioration. Drilling of the subchondral bone can lead to fibrocartilage formation and temporary repair that slowly degrades. Animal experiments indicate that introducing proliferating chondrocytes such as cu ltured articular chondrocytes can reliably reconstruct joint defects. Objectives: To describe our clinical experience in culturing and transplant ing autologous chondrocytes. Methods: Biopsies were obtained from 10 patients, aged 18-45, undergoing a routine arthroscopy in which a cartilage defect was identified with indicat ions for cartilage transplantation. The biopsies were further processed to establish chondrocyte cultures. ACT was performed in 8 of the 10 patients b ecause of persistent symptoms for at least 2 months post-arthroscopy. All p atients (6 men and 2 women) had a grade IV cartilage defect in the medial o r lateral femoral condyle, and three had a defect in the trochlear region a s well. Biopsies were removed from the lateral rim of the superior aspect o f the femur, and cells were cultured in a clean room. Following a 2 order o f magnitude expansion; cells were implanted under a periosteal flap. Result s: The eight patients implanted with autologous cells were followed for 6 m onths to 5 years (average 1 year). Complaints of giving-way, effusion and j oint locking resolved in all patients, and pain as assessed by the visual a nalogue score was reduced by an average of 50%. Follow-up magnetic resonanc e imaging studies in all patients revealed that the defects were filled wit h tissue having similar signal characteristics to cartilage. Conclusions: Chondrocyte implantation is a procedure capable of restoring n ormal articular cartilage in cases with isolated joint defects. Pain can be predictably reduced, while joint locking and effusion are eliminated. The effect on osteoarthritis progression in humans has not yet been elucidated.