Volumetric bone mineral density of the tibia is not increased in subjects with radiographic knee osteoarthritis

Osteoarthritis Cartilage. 2009 Feb;17(2):174-7. doi: 10.1016/j.joca.2008.06.004. Epub 2008 Aug 5.


Objectives: Radiographic osteoarthritis (ROA) has previously been shown to be associated with an increase in areal bone mineral density (BMD) as assessed by dual energy X-ray absorptiometry (DXA). Here we have assessed volumetric bone density, size and strength by peripheral quantitative computed tomography (pQCT) in a large population-based cohort study in which knee radiographs were available.

Methods: Two hundred and ninety-five men and 288 women from the MRC Hertfordshire Cohort Study underwent weight bearing extended knee X-rays and bone density measurement of the ipsi-lateral knee using pQCT.

Results: Increasing radiographic grade in men but not women was associated with an increase in tibial total area at 38% site and cortical area at 14% site, but not with volumetric BMD. The tibial fracture loads as well as tibial polar strength strain index at 38% site were also increased. There were no significant associations of tibia bone area, BMD or strength with radiographic grade in women.

Conclusion: ROA is not associated with an increase in volumetric BMD as assessed by pQCT. It is, however, associated with a significant increase in bone area and strength, indicating that the association between ROA and areal BMD is mediated through bone size rather than volumetric BMD.

MeSH terms

  • Absorptiometry, Photon
  • Aged
  • Bone Density / physiology*
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Osteoarthritis, Knee / diagnostic imaging
  • Osteoarthritis, Knee / physiopathology*
  • Tibia / diagnostic imaging
  • Tibia / physiopathology*
  • Tomography, X-Ray Computed