BACKGROUND:The regeneration ability of articular cartilage is limited.However,the emerging of tissue regeneration based on the use of autologous cells appears to offer great promise in repairing articular cartilage defects.OBJECTIVE:To evaluate the short-term effectiveness and safety of autologous chondrocyte implantation (ACI).DESIGN,TIME AND SETTING:A prospective study was performed at the eighty university hospitals and general hospitals in Korea from March 2001 to April 2006.PARTICIPANTS:Two hundred and sixty-one patients with articular cartilage injury of the knee were selected,including 169 males,92 females,with the mean age of 36.47 years (ranged:15-70 yeats old),and the mean size of chondral defect was 4.91 cm2 (ranged:2.0-20.0 cm2).Totally 215 cases were femoral condyle injury,30 cases with trochlear,25 cases with patellar,and 2 cases with tibia defects.METHODS:A total of 200-300 mg of cartilage tissue was obtained from a non-weight-bearing portion of the knee,followed by in society score after ACI was evaluated by Knee Society Score-A (KSS-A)and Knee Society Score-B (KSS-B)system.MAIN OUTCOME MEASURES:KSS-A and KSS-B score of defected areas after ACI.RESULTS:All patients Received: followed-up without any loss.The KSS-A was 63.55±18.47 and 88.74±11.47 prior to and at 6 months after implantation,the difference had significance (P＜0.05).The KSS-B was 59.56±24.92 and 85.13±14.67 respectively prior to and at 6 months after implantation,which had obviously difference (P＜0.05).The joint pain,activity,stability,flexion contracture,locomotor activity and stair climbing were obviously improved.The effective rate was 97.3% and excellent and good rate was 89.3%.CONCLUSION:ACI can achieve a good result in treating knee articular cartilage defects,which can encourage the recover of knee function.