There is limited information regarding direct comparisons of the outcome of osteochondral autograft transfer (OAT) mosaicplasty and microfracture for the treatment of isolated articular cartilage defects of the knee. The purpose of this retrospective comparative study was to compare the general health outcomes, knee function, and Marx Activity Rating Scale scores for patients treated with OAT or microfracture for symptomatic chondral defects of the femoral condyles or trochlea. We hypothesized that the patients in the two treatment groups would have similar clinical outcomes at intermediate-term follow-up.
Ninety-six patients with full-thickness cartilage defects of the femoral condyles or trochlea were treated with either OAT mosaicplasty (n = 48) or microfracture (n = 48). The average age of the patients (thirty-two male and sixteen female in each group) at the time of surgery was 29.7 years in the OAT group and 32.5 years in the microfracture group. Patients were prospectively evaluated at baseline and at one, two, three, and five years postoperatively with use of validated clinical outcome measures including the Short Form-36 (SF-36) physical component, International Knee Documentation Committee (IKDC), Knee Outcome Survey activities of daily living, and Marx Activity Rating Scale instruments. Comparisons between outcomes before and after treatment or between outcomes after microfracture and mosaicplasty were made with use of two-tailed tests.
At the time of the latest follow-up, both groups demonstrated significant increases in SF-36 physical component, Knee Outcome Survey activities of daily living, and IKDC scores compared with baseline. These scores did not differ significantly between the two groups at any of the follow-up time points. However, the OAT group demonstrated a significantly greater improvement in the Marx Activity Rating Scale scores from baseline to the two-year (p = 0.001), three-year (p = 0.03), and five-year (p = 0.02) time points compared with the microfracture group.
In the present retrospective comparative study, the hypothesis that patients treated with microfracture or OAT mosaicplasty for symptomatic articular cartilage defects of the femoral condyles or trochlea would have similar clinical outcomes at intermediate-term follow-up was affirmed for general health outcome and for knee function. However, patients treated with OAT mosaicplasty maintained a superior level of athletic activity compared with those treated with microfracture.