New Support for Bone Marrow Lesions as Predictors in Knee OA

Foong YC, Khan HI, Blizzard L, et al., The clinical significance, natural history and predictors of bone marrow lesion change over eight years. Arthritis Res Ther. (2014) Jul 14;16(4):R149. (Open access)

New or enlarged subchondral bone marrow lesions (BML) in knee osteoarthritis (OA) appear to be linked to an increase in pain over the years, according to a new study from Australia. This appears particularly true for men and for people with a family history of OA.

The study, which followed 198 men and women in their 50s (109 adult offspring of people who’d had a knee replacement and 89 controls) over a ten-year period also finds that body mass index and strenuous activity appear to be associated with an increase in the size of subchondral BMLs in knee OA.

Neither smoking nor the presence of radiographic damage were associated with BMLs in this study.

BMLs, also referred to as chronic bone marrow edema, arise in the subchondral bone as a result of damage from repetitive loading that does not heal properly. They are believed to play a key role in the pathogenesis of knee OA.

While the erosion of cartilage leading to joint space narrowing (JSN) is characteristic of OA, previous research has shown that the degree of JSN correlates poorly with the occurrence and severity of pain in knee OA. Loss of cartilage is believed to lead subchondral bone damage and bone marrow edema, which may be the source of pain in OA. People with painful knee OA are 2.5 times more likely to have BMLs.¹

The researchers say this is the first study to look at the natural history of BMLs beyond three years.