Autologous Cartilage Implantation vs Arthroscopic Debridement

82 patients aged 18-49 years with an isolated focal cartilage defect in the knee will be randomized to either receive autologous cartilage implantation or arthroscopic debridement. Both groups will then undergo a systematic physiotherapy training regime for 6-9 months. The Groups will then be compared for results, after 3, 6, 12 and 24 months, by using validated patient reported outcome scores (Lysholm, KOOS, Tegner) and EQ5D (European Quality of Life 5 dimensions) as well as clinical examination and radiological findings at 2 years (MRI).