Vertebral fractures in the elderly may be traumatic
MedWire News: Vertebral fractures in the elderly may be traumatic in origin, UK researchers have discovered in findings that contradict the assumption that such fractures are osteoporotic in origin.
The most common osteoporotic fracture is vertebral body fracture, and a moderate force from daily activity may be enough to induce fracture. However, a vertebral fracture in an elderly person may in fact be due to a traumatic event that occurred recently or many years previously, even when bone density was normal.
To investigate further,Michael Adams, from the University of Bristol, and colleagues studied 73 cadaveric specimens of two vertebrae with the intervening intervertebral disc and ligaments, from 27 donors aged an average of 74 years.
Dual-energy X-ray absorptiometry was used to measure areal bone mineral density (BMD) in the lateral projection. Each specimen was compressed to failure at 3 mm/s on a materials testing machine, to a maximum deformation of 4 mm to prevent gross destruction of the vertebra.
Radiographically, the algorithm-based qualitative (ABQ) method was used to designate the specimens as having detectable or no discernible fractures, while any fractures were further classified as osteoporotic and/or traumatic in origin.
While there was no correlation between vertebral BMD and age, there was a strong and significant linear relationship between BMD and load failure in both males and females. Restricting the analysis to vertebral levels T11-T15, the correlation coefficient for both genders combined was 0.64.
Thirty-one specimens were found to have no discernible fractures, 26 had traumatic fractures, and 16 had osteoporotic fractures. Traumatic fracture specimens and specimens with no discernible fractures failed at a significantly higher load than those with osteoporotic fractures, Traumatic fracture specimens had a significantly higher BMD than osteoporotic fracture specimens, at 0.668 and 0.454 g/cm2, respectively.
The team concludes in the journal Bone: “Our study is the first in which mechanically induced vertebral fracture has been evaluated radiologically using the ABQ method and additional criteria.
“The results... show that fractures distinguished radiologically as being ‘osteoporotic’ occurred at lower forces and in specimens with lower mean BMD compared to ‘traumatic’ fractures.”
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By Liam Davenport