Paul S. Mueller, MD, MPH, FACP reviewing Kim C et al. BMJ 2015 Dec 2
Researchers have evaluated concordance between frequent hip pain and radiographic hip osteoarthritis (OA) in only a few studies. In this analysis, investigators used data from two cohort studies to calculate the accuracy of hip x-rays as a diagnostic test for hip OA. Hip pain “localized to the groin or anteriorly” was used as the clinical gold standard for hip OA.
In the Framingham study (946 patients; mean age, 64), 16% of hips in patients with frequent hip pain had radiographic OA, and 21% of hips with radiographic OA were frequently painful. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of radiographic hip OA for hip pain localized to the groin were 37%, 91%, 6%, and 99%, respectively. In the Osteoarthritis Initiative study (4366 patients; mean age, 61), 9% of hips in patients with
frequent hip pain had radiographic OA, and 24% of hips with radiographic OA were frequently painful. For hip pain localized to the groin, the sensitivity, specificity, PPV, and NPV of radiographic hip OA were 17%, 94%, 7%, and 98%, respectively. For both analyses, results were similar for hip pain at other sites and with internal rotation.
In these analyses, most patients with frequent hip pain did not have radiographic hip OA, and most patients with radiographic hip OA did not have frequent hip pain. The authors recommend that clinicians consider patients with typical anterior hip pain to have OA and to treat them accordingly, even if x-rays are negative. However, a limitation of this study is lack of a validated gold standard for determining when anterior hip pain in fact is due to OA.
Kim C et al. Association of hip pain with radiographic evidence of hip osteoarthritis: Diagnostic test study. BMJ 2015 Dec 2; 351:h5983. (http://dx.doi.org/10.1136/bmj.h5983) Abstract/FREE Full Text