Long-term clinical and radiological assessment of untreated severe cartilage damage in the knee: a natural history study.

We aimed to evaluate whether and to what extent an isolated deep cartilage lesion localized within the tibiofemoral and the patellofemoral joint has an impact on the clinical outcomes and osteoarthritis (OA) progression when it is left untreated. From 1991 to 1994, 4121 consecutive knee arthroscopies were performed, and 37 of them in patients with a single isolated chondral lesion of Outerbridge grade 4 located within weight-bearing areas of the femoral and tibial condyles (FT group) and patella (P group). The lesion size ranged from 2 to 4 cm(2) . Outcomes were reported at a mean 15.3-year follow-up using the Lysholm score, the Tegner activity scale and the Womac score. The mean Lysholm, Tegner and Womac score in the FT group was 87.7, 5.6 and 88.7, respectively. In the P group, it was 83.8, 4.8 and 84.6, respectively (P<0.0.5). Osteoarthritic changes were found in 39% of the patients. There was no difference in OA severity between an injured and an uninjured knee. In patients of the FT group, there was a relationship between the incidence of tibiofemoral OA and patellofemoral OA (P=0.00075). Severe isolated single chondral damage left with no treatment has a limited influence on clinical outcomes and the development of OA.