Cartilage injuries over time are thought to increase the risk of osteoarthritis (OA). Microfracture is the most widely used marrow stimulation procedure, rated by many as a first-line treatment for smaller contained cartilage lesions. This study reports on the long-term results of a randomized, controlled trial comparing autologous chondrocyte implantation (ACI) with microfracture among patients with chronic cartilage defects.

Subjects were patients with relatively large chronic focal cartilage defects in the knee. The participants were randomized to undergo either ACI or microfracure. Data were collected using the International Cartilage Repair Society (ICRS), Lysholm, Short Form-36 (SF-36), and Tegner forms at the time of inclusion and at follow-up evaluations. Surgeries were considered to have fa 1 led if the patient needed a repeat surgery due to symptoms resulting from a lack of healing. At the time of final follow-up, standard radiographs were obtained.

At 15-year follow-up, the failure rate in the ACI group was 42.5%, and in the microfracture group was 32.5% (P＝0.356). Of the survivors who did not have a failure, both treatment groups had significant improvement in scores on the Lysholm, VAS for pain, and SF-36 physical component scores at the short, medium and long-term evaluations (P<0.05). No significant difference was found between the groups. At long-term follow-up, 50% of the patients had radiographic signs of early OA.

This study of patients with chronic cartilage defects treated with either microfracture or chondrocyte implantation found that, at 15-year follow-up, 37% had treatment failure, with no significant d ifference noted between groups in function or pain outcomes.