Objective: Although bone marrow lesions (BMLs) have been implicated in the pathogenesis of OA, their natural history in a healthy population is unknown. This study in a healthy, pain free population aimed to examine the natural history of BMLs; factors associated with incidence and progression of BMLs over 2 years; and whether incident BMLs are associated with the development of pain.
Methods: 271 subjects with no clinical knee OA, being pain free at baseline, underwent magnetic resonance imaging of their dominant knee at baseline and 2 years later. The presence of BMLs was assessed.
Results: In knees initially free of BMLs, incident BMLs developed in 14% of people over the study period. Increased BMI (OR 1.15 (95% CI 1.06-1.2) p=0.001) was associated with incident BMLs. Those who developed a BML were more likely to develop knee pain compared to those in whom no BML developed (OR 4.2 (95% CI 1.2-15.1) p=0.03). Among those in whom BMLs were present at baseline, 46% completely resolved. There was no association between age, gender and BMI and persistence of BMLs over 2 years.
Conclusion: In this healthy population, the rate of incident BMLs is lower than previously described in a population with OA. Incident BMLs are associated with increased BMI and the development of pain. Approximately half the BMLs present at baseline resolved. These data suggest that in pain free people with no clinical knee OA, BMLs are reversible and may provide a target for interventions aimed at the prevention of knee OA.