Influence of Cell Quality on Clinical Outcome After Autologous Chondrocyte Implantation

Background: Several factors influence clinical outcome after autologous chondrocyte implantation (ACI) for the treatment of cartilage defects of the knee joint. Hypothesis/Purpose: The aim of the present study was to investigate the influence of cell quality on clinical outcome after ACI. The hypothesis of the authors was that cell quality at the time of transplantation influences clinical outcome after ACI for cartilage defects. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 80 patients were included in the present study. Knee function was assessed before surgery as well as 6, 12, and 24 months after ACI using standard instruments (International Knee Documentation Committee [IKDC], Lysholm, and Tegner scores). Cell quality was evaluated by determination of antigen expression of CD44 expression, aggrecan, collagen type II, and cell viability. A linear regression analysis including preoperative knee function, defect size, defect location, defect origin, body mass index, patient age, and other parameters was performed to evaluate the influence of these parameters on postoperative knee function. Results: Preoperative IKDC score increased from 49.6 +/- 13.8 points to 75.5 +/- 14.6 points at 24 months (P < .05). Postoperative IKDC score at 6, 12, and 24 months was significantly influenced by collagen type II expression, CD44 expression, and cell viability (all P < .05). No correlation between aggrecan and outcome was found. Quantitative influence of individual factors differed between different time points. Conclusion: Cell quality seems to be one of many factors that influences clinical outcome after ACI in patients with cartilage defects of the knee joint. It constitutes one aspect among various others affecting clinical outcome.