摘要Background Matrix-induced autologous chondrocyte implantation(MACI)is the third generation tissue-engineering technique for the treatment of full-thickness articular cartilage defects.The aim of this study was to describe this new technique and the postoperative findings in adolescent knee with focal chondral defect.Methods The MACI consists of diagnostic arthroscopy and cartilage harvest,chondrocyte culture and seeding in tissue-engineering collagenous membrane,and implantation of the scaffold.Clinical outcome at minimum 1-year follow-up was assessed in seven patients(mean age(16.6±1.5)years;14-19 years)with full-thickness cartilage defects,with International Knee Documentation Committee(IKDC)score,the International Cartilage Repair Society(ICRS)score and the Knee Injury and Osteoarthritis Outcome Score(KOOS).Besides,MR imaging was performed with T1 and T2-weighted imaging and three-dimensional spoiled gradient-recalled(3D-SPGR)MR imaging.Results Clinical evaluation showed significant improvement and MRI analysis showed that the structure was homogeneous and the implant surface was regular and intact in six patients,but irregular in one.Of all the seven patients,the cartilage defect site was nearly totally covered by the implanted scaffold.Conclusions These results indicated that MACl technique is an option for cartilage defect in adolescent knee joint,especially large defect of over 2 cm2.Long-term assessment is necessary to determine the true value of this technique.