The Natural History of Bone Marrow Lesions in Community-Based Middle-Aged Women Without Clinical Knee Osteoarthritis

Objective: Bone marrow lesions (BML) have been implicated in the pathogenesis of osteoarthritis, yet their exact role, etiology, and natural history remain unclear. The aim of this study was to examine the natural history of BML in a healthy population and identify risk factors associated with their persistence and incidence. Methods: One hundred forty-eight healthy middle-aged women had magnetic resonance imaging performed on their dominant knee at baseline and 2 years later to assess the presence, natural history, and risk factors for persistence and incidence of BML. Results: Approximately 46% of BML present at baseline completely resolved over 2 years. "Large" BML had the potential to improve, while the majority of "very large" remained stable. In those women with no BML at baseline, approximately 9% developed a BML over 2 years, the majority in the medial compartment. There was a trend toward weight being a risk factor for the development of "very large" BM L (P = 0.08). Conclusions: The natural history of BML may be different in healthy persons compared with diseased states. The trend for weight as a risk factor for development of a "very-large" BML suggests there is potential to identify modifiable risk factors for BML in asymptomatic people and warrants further investigation. (C) 2009 Elsevier Inc. All rights reserved. Semin Arthritis Rheum 39:213-217