A study of the prevalence and associations of subchondral bone marrow lesions in the knees of healthy, middle-aged women

Objective: Bone marrow lesions (BMLs) have been shown to be associated with pain and progression of knee osteoarthritis (OA) in those with disease. The natural history of BMLs in a healthy population and their role in the pathogenesis of CA are unknown. The aim of this study was to determine the risk factors for BMLs in healthy subjects and the association of BMLs with knee structure. Methods: One hundred and seventy-six healthy, adult women with no history of knee injury, or clinical knee CA had magnetic resonance imaging performed on their dominant knee to assess BMLs, tibiofemoral cartilage defects, tibial cartilage volume and bone area. Results: Thirteen percent of subjects had knee BMLs. The prevalence was higher in the medial tibiofemoral compartment. There was a significant positive association between BMLs and cartilage defects after adjusting for the potential risk factors: age, height, weight and cartilage volume [odds ratio (OR) 1.78 (95% confidence interval [Cl] 1.12, 2.82), P = 0.01]. BML was positively associated with tibial plateau bone area in the lateral compartment [OR 1.67 (95% Cl 1.02, 2.71), P= 0.04]. There was no significant association between BMLs and cartilage volume. Independent risk factors for BMLs after adjustment were increasing height [OR 1.18 (95% Cl 1.02, 1.36), P= 0.02 for lateral compartment] and weight [OR 1.04 (95% Cl 1.01, 1.08), P = 0.005 for total knee]. Conclusion: These data support that BMLs are present in a similar distribution to tibiofemoral knee OA. Their presence is associated with risk factors (height and weight) for knee OA, and the early structural changes of knee CA in subjects without knee pain and thus no clinical disease. Longitudinal studies will clarify whether BMLs relate to the pathogenesis of clinical knee OA. (c) 2007 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.