Articular cartilage defects of the knee are a common condition diagnosed at arthroscopy. The management of these osteochondral lesions is controversial. We present our experience using carbon fibre implants to repair these defects in 18 patients. Eleven patients (61 per cent) had an osteochondral defect of the medial femoral condyle. Two patients had isolated patellar defects. The mean knee assessment and functional scores were 75 and 80 respectively using The Knee Society Clinical Rating System. Serial post-operative M.R.I. scanning revealed that there was no loss of implant position with an extensive local tissue response and good joint congruity. Overall, 11 patients (61 per cent) returned to their normal sporting activity, while 3 patients (18 per cent) had a poor result. One of these underwent a patellectomy. We conclude that carbon fibre implants may have a role to play in the management of osteochondral defects of the femoral condyles.