Hip Osteoarthritis May Not Be Apparent on X-Rays

A new study concludes that in the majority of cases, X-rays are not reliable for diagnosing hip osteoarthritis (OA).

Researchers at Boston University School of Medicine (BUSM; MA, USA), the University of California, San Francisco (UCSF; USA), and other institutions conducted a diagnostic test study in two cohorts to assess the usefulness of pelvic radiographs for hip OA. Using visual representation of the hip joint, participants reported on hip pain presence and location. The agreement between radiographic hip OA and hip pain was then analyzed, and for those with hip pain suggestive of hip OA they calculated the sensitivity, specificity, and positive and negative predictive value of radiographs as the diagnostic test.

The results showed that in the Framingham osteoarthritis study, among 946 participants only 15.6% of hips in those with frequent hip pain showed radiographic evidence of hip OA, and 20.7% of hips with radiographic hip OA were frequently painful. The sensitivity of radiographic hip OA for hip pain localized to the groin was 36.7%, specificity was 90.5%, positive predictive value was 6%, and negative predictive value was 98.9%; the results did not differ much for hip pain at other locations or for painful internal rotation.

In the osteoarthritis initiative study, which involved 4,366 patients, the results were even worse; only 9.1% of hips in patients with frequent pain showed radiographic hip OA, and 23.8% of hips with radiographic hip OA were frequently painful. The sensitivity of definite radiographic hip OA for hip pain localized to the groin was 16.5%, specificity was 95%, positive predictive value was 7.1%, and negative predictive value was 97.6%. Once again, the results did not differ much for hip pain at other locations. The study was published on December 2, 2015, in BMJ.

“Hip pain was not present in many hips with radiographic osteoarthritis, and many hips with pain did not show radiographic hip osteoarthritis,” concluded corresponding author Chan Kim, MD, of BUSM, and colleagues. “Most older participants with a high suspicion for clinical hip osteoarthritis did not have radiographic hip osteoarthritis. Given these findings, patients with suspected hip OA should be treated regardless of X-ray confirmation.”


The most common symptoms of hip OA are pain and decreased range of motion. Common signs and symptoms include aching and stiffness in the groin, buttock, or thigh; decreased range of motion; chronic hip swelling; hip crunching or popping; limping or lurching; and loss of hip joint function. Discomfort is usually most noticeable when getting out of bed in the morning and may flare up when participating in sports or other intense activities.

Related Links:
Boston University School of Medicine
University of California, San Francisco