This study was an open-label, multicenter extension to the SUMMIT study designed to examine the 5-year efficacy and safety of MACI compared to arthroscopic microfracture in the treatment of articular cartilage defects of the knee in participants who received study treatment in the SUMMIT study. Follow-up to 2 years post-study treatment was completed as part of the SUMMIT study. Follow-up from 3 to 5 years post-study treatment in SUMMIT was completed in this extension study.~All 144 participants who received study treatment in the SUMMIT study were eligible for enrollment into this extension study. Participants had until the end of the visit window for the last visit of this extension study (ie, Week 260 + 6 weeks) to consent to enter this extension study.~Efficacy and safety assessments were performed at scheduled visits 3, 4, and 5 years following treatment in SUMMIT (ie, at Weeks 156, 208, and 260 postarthrotomy for patients treated with MACI implant or at Weeks 156, 208, and 260 postarthroscopy for patients treated with microfracture).
To examine the 5-year efficacy and safety of MACI implant, compared with arthroscopic microfracture, in participants who received study treatment in the SUMMIT study for treatment of symptomatic articular cartilage defects of the knee.