A Study of MACI in Patients Aged 10 to 17 Years With Symptomatic Chondral or Osteochondral Defects of the Knee

This is a 2-year prospective, multicenter, randomized, open-label, parallel group clinical trial; a total of 45 participants, ages 10 to 17 years, will be randomized to receive a 1-time treatment with MACI or microfracture (2:1, 30 MACI:15 microfracture). After meeting screening criteria at the initial visit, all participants will have a screening arthroscopy to further assess study eligibility. During the screening arthroscopy, participants will be further evaluated against entry criteria. Cartilage lesion size will be measured prior to any cartilage repair procedure and randomization. All participants who meet the eligibility criteria and are considered suitable for treatment in the study will have a cartilage biopsy taken prior to randomization to study treatment. Eligible participants will be randomized during the screening arthroscopy procedure to receive either MACI or microfracture treatment. Participants randomized to microfracture will undergo the procedure during the screening arthroscopy. All biopsied tissue will be sent to the Vericel manufacturing facility in Massachusetts, where the sample will be processed to isolate the autologous chondrocytes. Cells from participants randomized to the MACI group will be used in the preparation of the MACI implant; cells from participants randomized to the microfracture group will be cryopreserved. Participants randomized to treatment with MACI will return within 12 weeks of the screening arthroscopy to undergo the chondrocyte implantation procedure via arthrotomy. Participants are to follow a recommended postoperative rehabilitation program and compliance with the rehabilitation schedule will be monitored. Participants will be followed post-study treatment for 2 years (104 Weeks).