This study aimed to characterize subchondral bone damages of knee osteoarthritis (OA) patients in presence of the comorbidities, i.e., hypertension and type 2 diabetes mellitus (T2DM).
A total of 43 patients with advanced stage of primary knee OA were recruited, and tibial plateau specimens were collected during surgery with informed consent. The specimens were processed for micro-CT and histological examination to assess the severity of subchondral bone damages. The presence of the comorbid disease, e.g., hypertension and T2DM, and the data on covariates, such as the age, gender and body mass index (BMI), were taken into account in a multi-variable linear regression model to explore the potential effect of the comorbidities on subchondral bone damages in knee OA after adjusting the covariates.
As compared to 15 subjects without the comorbidities, significant bone loss was observed at subchondral plate in 28 knee OA patients with hypertension and T2DM, in terms of the lower bone mineral density (BMD) (P = 0.034) and higher porosity (P = 0.032) on the medial portion of tibial plateau. After adjusting the age, gender and BMI, the presence of hypertension or T2DM was included in a regression model to explain in part the decreased BMD (r(2) = 0.551, P = 0.004) and increased porosity (r(2) = 0.545, P = 0.003) at subchondral plate in knee OA.
Our findings suggest the biological link between bone loss at subchondral bone plate in knee OA and the comorbid diseases, i.e., hypertension and T2DM, which prompt the needs for a large-scale cohort study to confirm the causality.