KNEE osteoarthritis was linked to lower tibial cortical volumetric bone mineral density despite slightly higher DXA BMD in midlife.
Study Design and Imaging Approach
Understanding bone health in knee osteoarthritis has been challenging, particularly because radiographic knee osteoarthritis is often associated with higher areal bone mineral density (aBMD), yet fracture risk may not differ from people without osteoarthritis. To clarify this apparent mismatch, investigators examined how radiographic knee osteoarthritis relates to volumetric bone mineral density (vBMD), which may better reflect cortical and trabecular bone characteristics at peripheral sites.
The study enrolled 2,450 adults aged 40 years or older, including 944 men and 1,506 women, randomly selected from Ho Chi Minh City, Vietnam. Knee radiographs were scored using the Kellgren and Lawrence scale, with Grade 2 or higher defining knee osteoarthritis. Areal BMD at the femoral neck and lumbar spine was measured using dual-energy X-ray absorptiometry (DXA), while trabecular and cortical vBMD at the tibia was assessed using peripheral quantitative computed tomography (pQCT).
Knee Osteoarthritis and Volumetric Bone Mineral Density
Radiographic knee osteoarthritis was common in this cohort, affecting approximately 31% of participants (n=755), with prevalence increasing with age. When comparing individuals with and without knee osteoarthritis, the investigators found a small but statistically significant increase in femoral neck aBMD among those with knee osteoarthritis (effect size 0.04; 95% CI: 0.02–0.05; p=0.0002).
In contrast, participants with knee osteoarthritis demonstrated lower cortical tibia vBMD (effect size −8.15; 95% CI: −14.52 to −1.8; p=0.01). This divergence suggests that higher DXA-derived aBMD measurements may not necessarily align with cortical bone characteristics at the tibia in knee osteoarthritis.
Clinical Interpretation
These findings support the concept that bone density relationships in knee osteoarthritis may depend on both skeletal site and measurement technique. While DXA may show slightly higher aBMD at central sites such as the femoral neck, tibial cortical volumetric bone mineral density may be reduced in knee osteoarthritis, potentially helping explain why fracture risk does not always track with DXA-based density patterns in this population.
Reference: Hoang DK et al. Association between knee osteoarthritis and volumetric bone mineral density. Osteoarthr Cartil Open. 2026;8(1):100740.
