Arthroscopic Second-Generation Autologous Chondrocyte Implantation Compared with Microfracture for Chondral Lesions of the Knee

Abstract

Background Various approaches have been proposed to treat articular cartilage lesions, which are plagued by inherent limited healing potential. Purpose To compare the clinical outcome of patients treated with second-generation autologous chondrocyte implantation implants with those treated with the microfracture repair technique at 5-year follow-up. Study Design Cohort study; Level of evidence, 2. Methods Eighty active patients (mean age, 29.8 years) and grade III to IV cartilage lesions of the femoral condyles or trochlea were treated with arthroscopic second-generation autologous chondrocyte implantation Hyalograft C or microfracture (40 patients per group). Patients achieved a minimum 5-year follow-up and were prospectively evaluated. Results Both groups showed statistically significant improvement of all clinical scores from preoperative interval to 5-year follow-up. There was a significant improvement for the International Knee Documentation Committee subjective score from preoperative to 5-year follow-up (Wilcoxon test, P < .001). In the microfracture group, the International Knee Documentation Committee objective score increased from 2.5% normal and nearly normal knees before the operation to 75% normal and nearly normal knees at 5-year follow-up, and the subjective score increased from 41.1 ± 12.3 preoperatively to 70.2 ± 14.7 at 5-year follow-up. In the group treated with Hyalograft C, the International Knee Documentation Committee objective score increased from 15% normal and nearly normal knees before the operation to 90% normal and nearly normal knees at 5-year follow-up, and its subjective score increased from 40.5 ± 15.2 preoperatively to 80.2 ± 19.1 at 5-year follow-up (Wilcoxon test, P < .001). When comparing the groups, better improvement of the International Knee Documentation Committee objective (P < .001) and subjective (P = .003) scores was observed in the Hyalograft C group at 5-year follow-up. The return to sports at 2 years was similar in both groups and remained stable after 5 years in the Hyalograft C group; it worsened in the microfracture group. Conclusion Both methods have shown satisfactory clinical outcome at medium-term follow-up. Better clinical results and sport activity resumption were noted in the group treated with second-generation autologous chondrocyte transplantation.