Does Bisphosphonate Increase the Sclerosis of Tibial Subchondral Bone in the Progression of Knee Osteoarthritis—A Propensity Score Matching Cohort Study Based on Osteoarthritis Initiative

Introduction Most studies have focused on the protective effect of bisphosphonate on early KOA through its anti-resorption mechanism in osteoclasts. However, late KOA has a decreased rate of resorption, which is the opposite of early KOA. The risk of subchondral bone sclerosis in late KOA after using bisphosphonate has not been investigated using morphometry. Methods Forty-five patients who had ever used bisphosphonate (or 33 patients with current use) were matched with controls through propensity matching methods, including age, BMI (body mass index), sex, health status (12-Item Short Form Survey physical health score), physical activity level (Physical Activity Scale for the Elderly score), vitamin D use, and calcium use. At the baseline and 12-month (or 18-month) follow-up, BMD (bone mineral density) of the tibia and hip was measured by DXA (dual-energy X-ray absorptiometry), and medial tibial subchondral bone morphometry: BV/TV (bone volume fraction), Tb.Th (trabecular thickness), Tb.N (trabecular number), and Tb.Sp (trabecular separation) were calculated based on 3-T trabecular MRI (magnetic resonance imaging). Data were obtained from the Bone Ancillary Study in the OAI project. Results The yearly percentage change in hip BMD of the current bisphosphonate use group was significantly greater than that of the non-bisphosphonate use group (0.7% vs. -1%, P=0.02). The other outcomes (BV/TV, Tb.N , Tb.Sp, Tb.Th , tibia medial BMD, tibia lateral BMD) between the two groups presented no significant difference. The non-bisphosphonate use group experienced a significant increase in Tb.Th (2%, 95% CI = [1%, 4%], P=0.01), while the bisphosphonate use group presented no significant change (1%, 95% CI = [-2%, 4%], P=0.54). Conclusion Bisphosphonate use did not increase sclerosis of subchondral bone in established KOA. Bisphosphonate might have a stage-dependent effect on subchondral bone in KOA initiation and progression.