Reconstruction of Osteochondral Defects by Combined Bone Grafting and a Bilayer Collagen Membrane as a Sandwich Technique

Treatment of osteochondral lesions of the knee remains a major challenge in orthopedic surgery. Recently established procedures like autologous chondrocyte implantation or matrix-associated chondrocyte implantation yield good results, but include the disadvantage of two-step procedures. The purpose of this study was to evaluate the clinical and magnetic resonance imaging outcome of repairs of osteochondral defects of the knee by a combined procedure of bone grafting and covering with a bilayer collagen membrane in a sandwich technique. Seven male patients with a mean age of 42 (range 30-55) years and symptomatic focal osteochondral lesions of the knee grade IV according to the International Cartilage Repair Society classification were included. The mean diameter of defects was 28.6 (range 15-40) mm. Results were evaluated at a minimum of 24 months after surgery by International Knee Documentation Committee score, Lysholm-score, visual analogue scale, and magnetic resonance imaging with specific cartilage sequences, evaluating the ICRS score and the Magnetic Observation of Cartilage Repair Tissue (MOCART) score. All patients judged the operation as successful. Among the patients available for the long-term follow-up, mean visual analogue scale value was 1.3 (range 0-3) out of 10 points. Mean International Knee Documentation Committee score was 80.8 (range 63.2-88.5) out of 100 points. Mean Lysholm score was 85 (range 55-95) out of 100 points. None of the patients had to be reoperated until today. Evaluation of magnetic resonance imaging using the MOCART score revealed a good correlation to the clinical outcome. This is the first study reporting results after reconstruction of osteochondral defects of the knee joint by bone grafting and a bilayer collagen membrane. This new method offers the advantage of a one-step-procedure and yields both good clinical and magnetic resonance findings. We conclude that this procedure can be a valuable tool to improve joint function after osteochondral defects, trauma, and in joints with local arthritic lesions.