Hip Pain and the Role of Diagnostic Imaging
Often in Physical Therapy we are asked if an image would help in our diagnosis or treatment of a patient's symptoms. The answer is very dependent on the individual patient's case but in most cases imaging has not been shown to improve outcomes. In prior posts we have discussed the strengths and limitations of diagnostic imaging such as MRI or x rays for musculoskeletal pain. One of the main limitations of these tests is the presence of both false negatives, the absence of pathology in those who have symptoms, or the more risky false positives, the presence of pathology in those who do not have symptoms. As our technology has improved we are able to view body structures in greater detail leading to "positive" findings even in asymptomatic people. These false positives may lead to unnecessary tests, medications, or procedures if they are not balanced by thorough clinical exam.
Recently researchers in the British Medical Journal published a study on the relationship between hip pain and x ray evidence of hip arthritis (OA) (Kim et al. 2015). The authors performed x rays on subjects and then interviewed these individuals for the presence of pain in the hip, groin, or low back. In one cohort of the study of >900 participants only 16% of painful hips showed evidence of OA (false negative) and only 21% of hips with the presence of OA were painful (false positive). Similarly, in a second cohort of >4300 patients the authors found only 9% of frequently painful hips showed signs of OA and 24% of hips with OA were painful.
The authors concluded that hip pain was not present in many hips with OA and many hips with pain did not not show signs of hip OA. The authors recommend utilization of a strong clinical examination prior to diagnosis based on diagnostic imaging alone. Visit your local Physical Therapist to assist in your evaluation and treatment of hip pain.