Hip pain was not present in many hips with radiographic evidence of osteoarthritis, and many people with painful hips did not have radiographic evidence of hip osteoarthritis, according to a diagnostic test study in which pelvic radiographs were assessed for hip osteoarthritis in 2 cohorts. Researchers determined:

• In the Framingham study (n=946), only 15.6% of hips in patients with frequent hip pain showed radiographic evidence of hip osteoarthritis, and 20.7% of hips with radiographic hip osteoarthritis were frequently painful.

• In the Osteoarthritis Initiative study (n=4,366), only 9.1% of hips in patients with frequent pain showed radiographic hip osteoarthritis, and 23.8% of hips with radiographic hip osteoarthritis were frequently painful.

• Clinicians should continue to evaluate and treat patients with hip pain suggestive of osteoarthritis despite negative radiographic findings.

Citation: Kim C, Nevitt MC, Niu J, et al. Association of hip pain with radiographic evidence of hip osteoarthritis: diagnostic test study. BMJ 2015;351:h5983. doi: 10.1136/bmj.h5983.

Commentary: This study validates an observation that I have heard many primary care physicians make, that patients who seem to have classic symptoms of osteoarthritis sometimes have negative x-rays. A challenge in this type of study is that there is no gold standard for making the diagnosis of osteoarthritis. The diagnosis of OA was made by the combination of pain in the groin associated with limited internal rotation or pain with internal rotation. While it is true that some people with a clinical diagnosis of OA might not have OA, the study makes an important point that clinical diagnosis, not just x-rays alone, should be an important criterion for making the diagnosis of osteoarthritis of the hip. —Neil Skolnik, MD