Minced cartilage implantation provides comparable outcomes to autologous chondrocyte implantation (ACI) for knee cartilage lesions: A matched‐pair analysis

PURPOSE: To compare short-term patient-reported outcomes (PROMs) and revision rates between autologous hand-minced cartilage implantation (MCI) and autologous chondrocyte implantation (ACI) for knee cartilage lesions. METHODS: All patients undergoing MCI or ACI at a single centre were retrospectively analysed from a prospectively maintained database. Propensity score matching was performed based on age, defect localisation, defect size, general health status (ASA class), and prior surgery. PROMs, including the COMI, IKDC score and VAS for pain, were obtained preoperatively and at 6, 12, and 24 months postoperatively. Statistical comparisons were performed for PROM absolute values, improvement from baseline, Patient Acceptable Symptom State (PASS) and Maximum Outcome Improvement (MOI). Postoperative complications and revision surgeries were also compared. RESULTS: After matching, 25 patients per group were compared. Both groups demonstrated statistically significant improvements in all PROMs when compared against baseline: COMI scores improved from 5.0 ± 1.5 to 2.6 ± 2.0 for ACI and from 5.3 ± 1.7 to 2.0 ± 2.0 for MCI. IKDC scores improved for ACI (49.8 ± 14.0 to 71.3 ± 18.7, p < .001) and MCI (49.4 ± 15.8 to 74.3 ± 15.9, p < 0.001). The VAS score for pain decreased significantly for both ACI (5.0 ± 2.2 to 2.2 ± 2.1, p < 0.001) and MCI (4.2 ± 2.5 to 2.2 ± 2.0, p < 0.001). ACI and MCI differed neither statistically nor clinically in PROMs. Gender, defect localisation, defect size, and concomitant interventions had no substantial influence on outcomes. Overall, 60% and 68% of ACI patients and 68% and 80% of MCI patients achieved PASS for IKDC and COMI scores at 24 months (p = n.s.). Re-operation rates were comparable between both groups. CONCLUSION: Patients undergoing single-stage MCI or two-stage ACI for medium to large knee chondral defects achieve comparable and favourable short-term outcomes with low rates for adverse event. MCI is an efficient and effective alternative treatment option for patients seeking a single-stage solution or in areas where ACI is inaccessible. LEVEL OF EVIDENCE: Level III.