Background: The optimal treatment for cartilage lesions has not yet
been established. The objective of this randomized trial was to compare
autologous chondrocyte implantation with microfracture. This paper represents
an update, with presentation of the clinical results at five years.
Methods: Eighty patients who had a single chronic symptomatic
cartilage defect on the femoral condyle in a stable knee without general
osteoarthritis were included in the study. Forty patients were treated with
autologous chondrocyte implantation, and forty were treated with
microfracture. We used the International Cartilage Repair Society, Lysholm,
Short Form-36, and Tegner forms to collect clinical data, and radiographs were
evaluated with use of the Kellgren and Lawrence grading system.
Results: At two and five years, both groups had significant clinical
improvement compared with the preoperative status. At the five-year follow-up
interval, there were nine failures (23%) in both groups compared with two
failures of the autologous chondrocyte implantation and one failure of the
microfracture treatment at two years. Younger patients did better in both
groups. We did not find a correlation between histological quality and
clinical outcome. However, none of the patients with the best-quality
cartilage (predominantly hyaline) at the two-year mark had a later failure.
One-third of the patients in both groups had radiographic evidence of early
osteoarthritis at five years.
Conclusions: Both methods provided satisfactory results in 77% of
the patients at five years. There was no significant difference in the
clinical and radiographic results between the two treatment groups and no
correlation between the histological findings and the clinical outcome.
One-third of the patients had early radiographic signs of osteoarthritis five
years after the surgery. Further long-term follow-up is needed to determine if
one method is better than the other and to study the progression of
Level of Evidence: Therapeutic Level I. See Instructions
to Authors for a complete description of levels of evidence.