Survival of autologous osteochondral grafts in the knee and factors influencing outcome.

ABSTRACT

The primary aim of this retrospective study was to determine the medium-term survival of autologous osteochondral grafts (mosaicplasty) in the knee. The secondary aims were to evaluate any reason for failure, and to ascertain if age, gender, BMI, previous or associated knee surgery, site or size of the osteochondral graft had any influence on outcome. Fifty-five patients undergoing an autologous osteochondral graft procedure between 1999 and 2008 were evaluated, with a mean follow-up of 5.9 years (range 0.5 to 10.5). Loosening, graft degeneration or subsequent surgery in the form of arthroplasty, revision autologous osteochondral graft or any other osteochondral procedure, and an Oxford knee score above 49.7 (see text) were considered as failure. Kaplan-Meier analysis demonstrated an 87.5% survival at 8 years (95% CI 72% to 97%). The mean Oxford score at follow-up was 163% (95% CI 10.6% to 22.1%) at follow-up. Two of 6 failures occurred in patients with varus malalignment. Linear regression analysis demonstrated an improved outcome in Oxford knee score in younger patients. Gender, BMI, previous or associated knee surgery, site and size of the graft had no influence on outcome. The authors consider autologous osteochondral grafting as a reliable method of treatment in the medium-term for young patients with small contained articular cartilage lesions up to 4 cm2. Careful attention should be paid to the mechanical axis (varus) prior to grafting. Long-term studies are necessary.