Microfracture Versus a Porcine-Derived Collagen-Augmented Chondrogenesis Technique for Treating Knee Cartilage Defects: Results at Midterm Follow-up

Background: Damaged cartilage can be treated using the creation of microfractures (MFxs) or the porcine-derived collagen-augmented chondrogenesis technique (C-ACT). Purpose: To provide the midterm results of a multicenter randomized controlled trial comparing MFx and C-ACT for knee cartilage defects. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: The study cohort comprised 36 patients with medial femoral condyle cartilage defects who were followed up for 6 years with clinical and magnetic resonance imaging data (n = 14 treated with MFx alone, n = 22 treated with C-ACT). Clinical outcomes were assessed preoperatively and at 1, 2, and 6 years postoperatively using a visual analog scale (VAS) for pain, the Knee injury and Osteoarthritis Outcome Score (KOOS), and the International Knee Documentation Committee (IKDC) subjective score. Magnetic resonance imaging scans were performed preoperatively and at 1 and 6 years postoperatively, and the repaired cartilage tissue was evaluated using the magnetic resonance observation of cartilage repair tissue (MOCART) score. The repaired tissue/reference cartilage ratio was quantified using T2 mapping. Adverse events during follow-up were also evaluated. Results: In both groups, the VAS pain score improved and was maintained for 1, 2, and 6 years postoperatively compared with preoperatively (P < .05 for all). Although there were no significant differences between groups in the VAS pain, KOOS, or IKDC scores at any time point, the change in the IKDC—Activities of Daily Living subscore from preoperatively to 6 years postoperatively was better in the C-ACT group than the MFx group (P = .0423). At 6 years postoperatively, the MOCART assessment showed superior results regarding the surface of the repair tissue in the C-ACT group compared with the MFx group (P = .0288). There were no differences between the groups in the total MOCART score or other subscores. Conclusion: The study results suggest that C-ACT has similar effects to MFx in improving pain, joint function, and imaging findings and may be superior to MFx in improving daily life function and improving the quality of the surface of the cartilage tissue. Registration: ClinicalTrials.gov identifier: NCT02539030.