112 participants with a symptomatic isolated International Cartilage Repair Society Grade III or IV cartilage lesion of the femoral condyles were randomized to receive characterized chondrocyte implantation (CCI) or microfracture. The results from 60 month follow-up indicated there were no significant differences between the two groups, in regards to change in Knee Injury and Osteoarthritis Outcome Scores (KOOS) from baseline. However, through subgroup analysis, it was found that patients who received CCI had better KOOS scores with time since the symptom onset less than 3 years.