X-rays could miss out on bone fractures. Up to nearly a third of fractures in the bones of the hip and pelvis could thus fail to be spotted.
Researchers with the Duke University Medical Center, Durham, North Carolina sought to evaluate the detection of hip and pelvic fractures with radiography in the emergency department.
All MR images of the lower extremity or pelvis ordered from July 2005 through June 2008 by the emergency department after the patient had undergone radiography were retrospectively reviewed in consensus by two musculoskeletal radiologists. All radiographs and MR images were reviewed in regard to patient age and sex, MRI protocol, site of fracture, fracture identification, other possible pain generators, and unexpected findings. Receiver operating characteristics analysis was performed on the findings.
Reporting their findings in the American Journal of Roentgenology, Dr Charles Spritzer and his colleagues said, "A total of 92 patients and 97 examinations were included. Our patient sample (77 women, 15 men; average age, 70.8 years; range, 19-94 years) had an elderly female bias. Sixty-five of the patients had a history of trauma. Thirteen patients (14%) with normal radiographic findings were found to have 23 fractures at MRI (six hip and 17 pelvic fractures). In 11 patients (12%) MRI showed no fracture after radiographic findings had suggested the presence of a fracture. In another 15 patients who had abnormal findings on radiographs, MRI depicted 12 additional pelvic fractures not identified on radiographs. In 43 of the 59 patients (73%) without MRI evidence of a fracture, the MRI findings suggested the presence of a potential pain generator, including muscle edema and tears, trochanteric bursitis, and hamstring tendinopathy...
"Our study showed poor sensitivity of radiography in the evaluation of hip and pelvic pain in the emergency department."
Dr Charles Spritzer said: "The diagnosis of traumatic fracture most often begins and ends with X-rays of the hip, pelvis, or both.
"In some cases though, the exclusion of a traumatic fracture is difficult."
The researchers say it is worth using MRI as well as an X-ray if doctors are in any doubt, particularly since hip patients tend to be frail and elderly with a higher than average risk of complications and death.
Dr Spritzer said: "Accurate diagnosis of hip and pelvic fractures in the emergency department can speed patients to surgical management, if needed, and reduce the rate of hospital admissions among patients who do not have fractures.
"Use of MRI in patients with a strong clinical suspicion of traumatic injury but unimpressive X-rays has a substantial advantage in the detection of pelvic and hip fractures."
Dr Tony Nicholson, from the Royal College of Radiologists, said the findings quantified something already known or suspected.
But he did not think it would be feasible or sensible to give every patient an MRI scan.
"Ultimately, it comes down to clinical acumen. If an elderly patient has persistent pain even though their X-ray shows only minor arthritis, an MRI would be a very reasonable request to check that there is not a fracture.
"It is always worrying when something is not diagnosed immediately, but I think most clinicians are first class and would follow up a patient appropriately."