Although mention of hip pain usually triggers a physical examination followed by an X-ray, hip osteoarthritis might be missed if practitioners rely only on hip radiographs, say researchers from Boston University, University of California, Tufts Medical Center, and others.
Their study found that most older patients with frequent hip pain did not have radiographic hip osteoarthritis and vice versa. They analyzed data from pelvic radiographs in 2 groups: the Framingham Osteoarthritis Study and the Osteoarthritis Initiative.
The Framingham study had radiographic evidence of hip osteoarthritis present in only 16% of 946 patients with frequent hip pain; 21% of hips with radiographic hip osteoarthritis were frequently painful. Sensitivity of X-ray for hip pain localized to the groin was 37%, specificity 91%, positive predictive value 6.0%, and negative predictive value 99%. Factoring in painful internal rotation did not change the outcomes.
Among the 4,366 Osteoarthritis Initiative patients, only 9% of those with painful hips showed X-ray evidence of osteoarthritis, and 24% of those with radiographic evidence of osteoarthritis were painful. The sensitivity was 17%, specificity 94%, positive predictive value 7%, and negative predictive value 98%.
The researchers note that inadequate recognition of osteoarthritis has consequences in older patients, such as increased morbidity from heart disease, lung disease, diabetes, and frailty. Health professionals should continue with the evaluation and treatment of osteoarthritis, they conclude, despite negative radiographic findings.
Source:
Kim C, Nevitt MC, Niu J. et al. BMJ. 2015;351:1-8.
doi: 10 .113 6/bmj.h5983.