ObjectiveTo evaluate efficacy and safety at 5 years after treatment with hydrogel-based autologous chondrocyte implantation (ACI) for large cartilage defects in the knee.DesignProspective, multicenter, single-arm, Phase III clinical trial. ACI was performed in 100 patients with focal full-thickness cartilage defects ranging from 4 to 12 cm2 in size. The primary outcome measure was the responder rate (defined as improvement by ≥10 points) at 2 years using the Knee Injury and Osteoarthritis Outcome Score (KOOS).ResultsThe preoperative overall KOOS was 39.8 points and continuously increased to 84.7 points at 5 years (mean increase 44.1 points, 95% CI = 40.4-47.9, P < 0.0001). The primary study endpoint (i.e., a KOOS responder rate of >40%) was descriptively met at each assessment timepoint from 3 months to 5 years (Month 3: 75.5%, 95% CI = 65.6-83.8; Year 2: 93.0%, 95% CI = 86.1-97.1, Year 5: 92.8%, 95% CI = 85.7-97.0). International Knee Documentation Committee (IKDC) subjective and objective scores and quality of life assessments (EQ-5D-5L) supported the results seen for the KOOS. The overall treatment failure rate at 5 years was 1%. All treatment-related adverse events were of mild or moderate intensity and mostly occurred within the first year after treatment.ConclusionsHydrogel-based ACI has been shown to be a safe and effective treatment option for patients with large knee cartilage defects with sustained efficacy up to 5 years as demonstrated by consistent and clinically relevant improvements in all investigated efficacy variables. No remarkable adverse events or safety issues were noted.

Centrum for Orthopaedics and Sports Zürich Switzerland

Clinic of Traumatology Faculty of Medicine Masaryk University Brno and Úrazová Nemocnice Brno Czech Republic

Clinic of Traumatology Jász Nagykun Szolnok County Hetényi Géza Hospital Szolnok Hungary

Department of Orthopaedics and Trauma Surgery Medical Center Faculty of Medicine Albert Ludwigs University of Freiburg Freiburg Germany

Department of Orthopaedics and Traumatology 2nd Faculty of Medicine Charles University and Motol University Hospital Praha Czech Republic

Department of Orthopaedics Hospital Hořovice Hořovice Czech Republic

Department of Orthopaedics Szabolcs Szatmár Bereg County Hospitals University Teaching Hospital Nyíregyháza Hungary

Department of Orthopaedics University Hospital Ostrava Ostrava Poruba Czech Republic

Department of Traumatology and Orthopaedics University of Szeged Szeged Hungary

High Field MR Center Department of Biomedical Imaging and Image Guided Therapy Medical University of Vienna Vienna Austria

Hospital of Lithuanian University of Health Sciences Kaunas Clinics Kaunas Lithuania

Klaipeda University Hospital Klaipeda Lithuania

Lithuanian University of Health Sciences Ortopedijos Technika Kaunas Lithuania

OCM Clinic Munich Germany

Octane Biotherapeutics Inc Breinigsville PA USA

Orthopaedic Department Hospital Benešov Benešov Czech Republic

TETEC Tissue Engineering Technologies AG Reutlingen Germany

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