Early postoperative adherence of matrix-induced autologous chondrocyte implantation for the treatment of full-thickness cartilage defects of the femoral condyle

Matrix-induced autologous chondrocyte implantation (MACI) is a tissue-engineering technique for the treatment of full-thickness articular cartilage defects and requires the use of a three-dimensional collagen type I-III membrane seeded with cultured autologous chondrocytes. The cell-scaffold construct is implanted in the debrided cartilage defect and fixed only with fibrin glue, with no periosteal cover or further surgical fixation. In a clinical pilot study, the MACI technique was used for the treatment of full-thickness, weight-bearing chondral defects of the femoral condyle in 16 patients. All patients were followed prospectively and the early postoperative attachment rate, 34.7 days (range: 22-47) after the scaffold implantation, was determined. With the use of high-resolution magnetic resonance imaging (MRI), the transplant was graded as completely attached, partially attached, or detached. In 14 of 16 patients (87.5%), a completely-attached graft was found, and the cartilage defect site was totally covered by the implanted scaffold and repair tissue. In one patient (6.25%), a partial attachment occurred with partial filling of the chondral defect. A complete detachment of the graft was found in one patient (6.25%), which resulted in an empty defect site with exposure of the subchondral bone. Interobserver variability for the MRI grading of the transplants showed substantial agreement (kappa=0.775) and perfect agreement (kappa(w)=0.99). In conclusion, the implantation and fixation of a cell-scaffold construct in a deep cartilage defect of the femoral condyle with fibrin glue and with no further surgical fixation leads to a high attachment rate 34.7 days after the implantation, as determined with high resolution MRI.