RecruitingPhase 3Biological interventionA Study of MACI in Patients Aged 10 to 17 Years With Symptomatic Chondral or Osteochondral Defects of the KneeThe objective of this study is to compare the efficacy and safety of MACI® vs arthroscopic microfracture in the treatment of patients aged 10 to 17 years with symptomatic articular chondral or osteochondral defects of the knee.