Sequential outcome following autologous chondrocyte implantation of the knee: a six-year follow-up.

This prospective six-year longitudinal study reviews the clinical outcome of patients undergoing autologous chondrocyte implantation (ACI) and a porcine type I/III collagen membrane cover for deep chondral defects of the knee. We present 57 patients (31 male, 26 female) with a mean age of 31.6 years (range 15-51 years) that have undergone ACI since July 1998. The mean size of the defect was 3.14 cm(2) (range 1.0-7.0 cm(2)). All patients were assessed annually using seven independent validated clinical rating scores with the data analysed using ANOVA. ACI using a porcine type I/III collagen membrane cover produced statistically significant improvements (p < 0.001), maintained for up to six years, in knee symptoms compared to pre-operative levels. This study provides evidence of the medium-term benefit achieved by transplanting autologous chondrocytes to osteochondral defects.