Is Distal Forearm DXA a Useful Screening Tool for Fragility Fractures?

Women who are at risk for distal radial fractures may benefit from a forearm dual-energy x-ray absorptiometry (DXA) scan that assesses local bone loss, according to results of a retrospective case-control study. The findings suggest that DXA may aid in the early identification of patients who require intervention for osteoporosis.

This conclusion comes after the researchers determined that some postmenopausal women exhibited bone loss preferentially at the distal part of the radius and, in turn, are at higher risk for fragility fractures.

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“Our results highlight the existence of this subpopulation of postmenopausal women who might have a higher risk of distal radial fractures, which we believe to be a novel finding of this study,” the study authors wrote.

To evaluate the effectiveness of DXA as a screening tool for fragility fracture risk, the researchers analyzed data on 110 postmenopausal women who had sustained a distal radius fracture and data on 95 postmenopausal women with no fracture history.

Based on bone mineral density (BMD), T-score, and the proportion of patients with a T-score of –2.5 standard deviations (SD) or less, the researchers compared the two groups’ DXA measurements at the spine, hip, and distal part of the forearm (ultra-distal, mid-distal, and one-third distal sections).

Compared with the women with no fracture history, the women who had sustained a distal radius fracture had significantly lower BMD and T-scores. The fracture group also had higher proportions of patients with a T-score of –2.5 SD or less at the ultra-distal, mid-distal, and one-third distal forearm. The difference in spine and hip measurements was not significant between the groups.

Based on the T-score among the skeletal sites, the researchers also assessed regional differences. Women with fracture history had significantly lower T-scores than women without fracture. The fracture group also had a significantly higher proportion of patients with a T-score of –2.5 SD or lower for the 3 distal forearm sites compared with the spine and hip.

To validate the reliability of distal forearm DXA measurements, the study authors evaluated the statistical correlation (r) with volumetric BMD by computed tomography (CT). DXA measurements at all three of the distal forearm regions correlated highly with volumetric BMD by CT scan (r = 0.83 to 0.92).

—Colleen Murphy

Reference:

Miyamura S, Kuriyama K, Ebina K, et al. Utility of distal forearm DXA as a screening tool for primary osteoporotic fragility fractures of the distal radius. JB JS Open Access. 2020;5(1):e0036. doi:10.2106/JBJS.OA.19.00036.