Biphasic cartilage repair implant versus microfracture in the treatment of focal chondral and osteochondral lesions of the knee: a prospective, multi-center, randomized clinical trial

Autologous minced cartilage is a method for cartilage defect repair, and our study focuses on a newly developed biphasic cylindrical osteochondral construct designed for use in human knees. We aimed to compare its clinical effectiveness and safety with microfracture, the commonly utilized reparative treatment for knee chondral or osteochondral defects.

Conducted as a prospective multicenter, randomized controlled, non-inferiority trial across nine hospitals, the study involved 92 patients with International Cartilage Repair Society (ICRS) grade 3 to 4 chondral or osteochondral lesions on femoral condyles. Patients were evenly randomized to receive either the biphasic cartilage-repair implant (BiCRI) or microfracture. Functional outcomes and safety assessments were conducted at postoperative intervals of 6 weeks and 3, 6, and 12 months. Primary and secondary endpoints included International Knee Documentation Committee (IKDC) 2000 Subjective Knee Evaluation Form score improvement, the grade distribution in the IKDC 2000 Knee Examination Form, and various assessments, such as the Knee Injury and Osteoarthritis Outcome Score (KOOS), visual analog scales (VASs) for pain, MRI findings, and arthroscopic findings at 12 months.

Out of the initial participants, 47 in the BiCRI group and 45 in the microfracture group completed the follow-up. At 12 months, the mean change in IKDC total score was 25.56 ± 18.48 for BiCRI and 27.51 ± 23.65 for microfracture. The 95% confidence interval (CI) for the score difference (BiCRI minus microfracture) was − 6.95, exceeding the non-inferiority margin of − 12. Secondary endpoints indicated comparable functional outcomes, and arthroscopic findings demonstrated more fully regenerated cartilage in the BiCRI group.

Based on the IKDC 2000 Subjective Knee Evaluation Form score, BiCRI proved non-inferior to microfracture at 12 months. Short-term functional outcomes were comparable to those with microfracture, while arthroscopic findings showed more complete cartilage regeneration in the BiCRI group. Consequently, BiCRI emerges as a viable alternative for treating chondral or osteochondral defects.

Level 2, multi-center, randomized clinical trial.