Low proximal tibial trabecular bone mineral density (BMD) may play a role in the development of osteoarthritis-related knee pain, a new study suggests.
Knee osteoarthritis is characterized by changes in cartilage and subchondral bone and pain is often the primary sign that a patient may have osteoarthritis, the researchers noted, but the exact origin of pain within the knee joint is poorly understood because the pain could be related to many structural factors, such as altered joint alignment, bone marrow lesions, and cysts.
To date, research investigating the association between osteoarthritis-related knee pain and bone has focused primarily on bone near the subchondral surface, and there have been no specific studies reporting the relationship between epiphyseal or metaphyseal trabecular BMD and pain.
Led by Wadena D. Burnett of the University of Saskatchewan in Canada, researchers writing in Arthritis Research & Therapy set out to examine the relationships between proximal tibial trabecular (epiphyseal and metaphyseal) BMD and osteoarthritis-related pain in patients with severe knee osteoarthritis.
The study included 42 participants with osteoarthritis, recruited before total knee replacement surgery. Osteoarthritis severity was classified using Kellgren-Lawrence scoring, and pain severity was measured at the affected knee joint using the pain subsection of the Western Ontario McMasters Osteoarthritis Index (WOMAC). The researchers also used the Self-Administered Comorbidity Questionnaire to assess participants for any potential confounding comorbidities, such as diabetes and heart disease.
The researchers used 3-dimensional image processing techniques and a custom algorithm developed specifically for this study. Repeatability of the algorithm was assessed on an independent sample of healthy participants and participants with osteoarthritis using recommended methods.
The novelty of this study was focusing the analysis in the epiphyseal and metaphyseal trabecular regions, which are largely void of cysts, to determine any potential independent associations between BMD and pain.
“Our regression models suggested that tibial epiphyseal and metaphyseal BMD independently explained variance in total pain in patients with osteoarthritis prior to [total knee replacement],” the researchers concluded. “Patients with lower BMD tended to have higher levels of pain.”
Burnett WD, Kontulainen SA, McLennan CE, et al. “Proximal tibial trabecular bone mineral density is related to pain in patients with osteoarthritis.” Arthritis Res Ther. 2017;19:200. doi: 10.1186/s13075-017-1415-1419.