SAN DIEGO — Scanning just the dominant forearm of patients with a history of nondominant wrist fracture can miss cases of osteoporosis.
More cases of osteoporosis were diagnosed when both forearms were scanned with dual-energy x-ray absorptiometry (DXA) than when the dominant side alone was scanned, Pam Johnson reported during a poster session at the annual meeting of the International Society for Clinical Densitometry.
“We're missing 10%–15% of cases by doing [a scan of] just the dominant forearm, which is the rule” in these cases, Ms. Johnson, a certified radiologic technologist with the St. Paul, Minn.-based HealthEast Osteoporosis Care Clinic, said in an interview. “That [rule] should be reevaluated.”
In what she said is the first study of its kind, Ms. Johnson and her associates performed bilateral forearm DXA scans on 39 patients with a history of nondominant forearm fractures.
The mean one-third radius bone mineral density T score was −2.0 on the dominant side and −2.2 on the nondominant side. The nondominant radius DXA scan identified osteoporosis in 17 patients, 4 of whom were osteopenic on the dominant side.
The dominant radius DXA scan identified osteoporosis in 16 patients, 3 of whom were not osteoporotic on the nondominant side.
In addition, the researchers found that one patient had a normal T score on the dominant side but had osteopenia on the fractured, nondominant side.
“The number of patients diagnosed with osteoporosis increased from 16 to 20 if we scanned both the dominant and nondominant forearm, compared with scanning just the dominant side alone in the situation of a nondominant wrist fracture,” the researchers wrote in their poster. “Overall, 10% more patients were diagnosed with osteoporosis when both forearms were scanned.”
A key limitation of the study is its small sample size. Another, they wrote, is the fact that “forearm fracture history was not adjudicated but taken from personal history and therefore the location of the fracture may not always be correct.”
An estimated 250,000 wrist fractures occur each year in the United States.