The aim of this study was to evaluate the progression of osteoarthritis (end-stage disease with a requirement for arthroplasty) in patients with focal cartilage defects of the medial knee compartment.
Patients (n = 115) with focal cartilage lesions of the medial knee compartment underwent arthroscopy. The follow-up was performed 10 years after the operation to determine the rate of arthroplasty conversion and to evaluate associated factors.
In a total of 35 cases an arthroplasty was needed (30.4 %). The mean survival to arthroplasty was 93.2 (95 % CI 85.4-109.0) months. Cartilage defects within the femur and cartilage lesions within the patella and the lateral did not influence the OA progression. Among the significant risk factors for OA progression were higher patient age, female gender, overweight or obesity and severity of meniscal damage. The most important risk factor was the occurrence and the extent of tibial cartilage defects.
In the natural course, about 30 % of patients with focal cartilage defects of the medial knee compartment undergo rapid OA progression (arthroplasty as end-stage of the disease). There are general risk factors (age, female gender and obesity) but also local risk factors. Furthermore, tibial defects and the extent of meniscus loss influence the outcome significantly. These general and local factors should be more carefully estimated or addressed in future clinical and scientific work.