Cell-free cartilage repair in large defects of the knee: increased failure rate 5 years after implantation of a collagen type I scaffold.

ABSTRACT

INTRODUCTION: Cartilage defects of the knee remain a challenging problem in orthopedic surgery despite the ongoing improvements in regenerative procedures such as the autologous chondrocyte transplantation. Due to the lack of donor-site morbidity and the single-stage procedure cell-free scaffolds are an interesting alternative to cell-based procedures. But as currently mid- and long-term data are lacking, the aim of the present study was to present mid-term clinical, radiological and histological results of a cell-free collagen type I scaffolds for cartilage repair. MATERIALS AND METHODS: Twenty-eight patients were followed prospectively. Clinical evaluation using patient-reported outcome measures (KOOS, IKDC; VAS for pain, Tegner score for activity) as well as radiologic evaluation of the repair tissue (MOCART) was performed at 1 year, 2 years and 5 years. Histologic evaluation of the repair tissue was done in case of revision surgery using the ICRS II score for human cartilage repair. RESULTS: In these large cartilage defects with a mean defect size of 3.7 ± 1.9 cm2, clinical failure necessitating revision surgery was seen in 5 of 28 patients (18%). While the remaining patients showed good-to-excellent clinical results (KOOS, IKDC, VAS, Tegner), the radiologic appearance of the repair tissue showed a reduction of the MOCART score between the 2- and 5-year follow-up. Histologic evaluation of the repair tissue showed a cartilage-like appearance with no signs of inflammation or cell death but an overall medium tissue quality according to the ICRS II Score. CONCLUSION: The use of this cell-free collagen type I scaffold for large defects showed increased wear of the repair tissue and clinical failure in 18% of cases at 5-year follow-up.