Accuracy of diagnostic injection in differentiating source of atypical hip pain.

It is not uncommon to encounter patients with atypical hip or lower extremity pain, ill-defined clinicoradiological features, and concomitant hip and lumbar spine arthritis. The purpose of this study is to present our experience using the response resulting from a combined anesthetic-steroid hip injection for treatment selection in these patients. A retrospective analysis of 204 consecutive diagnostic hip injections was undertaken. Patient charts were scrutinized for outcomes of injection and treatment. Our findings suggest that the relief of symptoms following injection of local anesthetic and steroid into the hip joint has a sensitivity of 91.5%, specificity and positive predictive value of 100%, and negative predictive value of 84.6% for response to total hip arthroplasty. We thereby believe that this is a reliable test with low morbidity and can predict the potential benefit of total hip arthroplasty in this diagnostically challenging group of patients. Copyright 2010 Elsevier Inc. All rights reserved.