Malalignment: a possible target for prevention of incident knee osteoarthritis in overweight and obese women.

OBJECTIVES The present study aims to investigate the associations between malalignment and incident knee OA after 2.5 years in a high-risk group of 333 middle-aged overweight women (BMI ≥ 27 kg/m(2)) free of clinical and radiological knee OA at baseline. METHODS The primary outcome measure was the incidence of knee OA, defined as the incidence of radiographic knee OA (Kellgren and Lawrence grade ≥2), clinical knee OA (ACR criteria) or medial or lateral joint space narrowing (≥1.0 mm). Using generalized estimating equations, associations between valgus and varus alignment (compared with neutrally aligned knees) and the primary outcome measure and all its items separately were studied. RESULTS Neither varus- nor valgus-aligned knees had a significantly increased risk for incident knee OA according to the primary outcome measure. A significantly increased risk for the development of radiographic knee OA was found for varus-aligned knees [odds ratio (OR) 3.3, 95% CI 1.5, 7.3]. Valgus-aligned knees showed a borderline increased OR (2.8, 95% CI 1.0, 8.0) for the development of radiographic knee OA. No statistically significant effects were found for varus and valgus alignment on the incidence of clinical knee OA or medial or lateral joint space narrowing. CONCLUSION Since this study was performed in a true target population, current data suggest that malalignment might be a target for the prevention of radiographic knee OA in overweight and obese women.