Results at 10-14 years after microfracture treatment of articular cartilage defects in the knee

To evaluate the long-term clinical outcome after microfracture treatment of focal chondral defects of the knee and to investigate possible early determinants of the outcome. A prospective cohort of 110 patients, treated with microfracture, was evaluated at a median of 12 years (range 10-14) by Lysholm score, VAS of knee function and VAS of knee pain. Pre- and perioperative information was collected, and additional surgery to the same knee during the follow-up period was recorded. Analysis of variance and paired t test were used for comparison of the long-term data to results from the baseline examination and a former 5-year (midterm) follow-up evaluation. Forty-three patients needed additional surgery to the knee including seven knee replacements. Fifty had a poor long-term outcome-defined as a knee replacement surgery or Lysholm score below 64. A poor result was more common in subgroups with mild degenerative changes in the cartilage surrounding the treated defect, concurrent partial meniscectomy, poor baseline Lysholm score or long-standing knee symptoms. The Lysholm score, function VAS and pain VAS all significantly improved from the baseline values to the mean scores of 65 (SD 24), 65 (SD 24) and 31 (SD 24), respectively, at the long-term evaluation. The long-term scores did not differ significantly from the midterm scores. The outcome scores improved significantly from baseline to the long-term evaluation and were not different from the midterm outcome. Still, a normal knee function was generally not achieved, and many patients had further surgery. The results call for more research and, at present, caution in recommending microfracture in articular cartilage defects, especially in subgroups with worse prognosis. Case series, Level IV.