Efficient radiological assessment of the internal snapping hip syndrome

The aim of this study was to evaluate the diagnostic value/significance of various imaging techniques for demonstrating the underlying causative patho logy of clinically suspected internal snapping hip syndrome. We intended to define the most efficient diagnostic imaging algorithm that leads to a spe cific definite therapy for this rare hip disorder. The imaging studies of 5 4 patients (43 women, 11 men, average age 58 years) with the clinical suspi cion of internal snapping hip syndrome were compared for their diagnostic v alue/significance for finding the underlying pathology. Radiological workup included plain radiographs of the pelvis and hip joints (n = 54), ultrasou nd (US) of the hip joints (n = 29), computed tomography (CT) of the pelvis and proximal femur (n = 17), and magnetic resonance imaging (MRI) of the pe lvis/hip joint (n = 21). In order to establish an efficient diagnostic algo rithm we compared the diagnostic value of each imaging technique alone and in combination with the other methods. The underlying causative pathology c ould be established in 37% of patients (n = 20) by the use of conventional radiographs alone and in 46% of the patients (n = 25) by US alone, and in c ombination in 83% of the patients (n = 45). By adding CT to the radiologica l workup, we established final diagnosis in 88% (in combination with X-ray; n = 15/17) and 94% (together with X-ray and US; n = 16/17) of the patients . Whenever MR imaging was used a causative pathology was found in all patie nts (100%; n = 21). The most efficient radiological algorithm in the assess ment of patients with internal snapping hip syndrome is the combination of plain radiography and US. MR imaging can be retained for unresolved and dif ficult cases.