Radiographic signs of retroversion of acetabulum in adult Indian population, retrospective observational study

Abstract

Introduction: Hip joint is commonly affected by osteoarthritis in Indian population and incidence of pain in hip and osteoarthritis is increasing in Indian population also. Retroversion of acetabulum is a type of hip dysplasia and a common cause of hip pain and Osteoarthritis of hip. Radiographic Diagnosis of the retroversion of Acetabulum is based on three signs: cross over sign (COS), posterior wall sign (PWS), prominent ischial spine sign (PRISS). All these signs are well described in literature and most of the Orthopedic surgeons don’t know the significance of these signs. Method: We evaluated 372 normal adult radiographs of pelvis from our radiology department to find out the prevalence of these signs in our hospital population. We also correlated the crossover ratio (percentage of crossover) to the presence of other two signs. In 372 normal pelvis radiographs 744 hips were analyzed for presence or absence of these 3 signs and the measurement of crossover ratio was done in AGFA workstation. Results: The prevalence of COS is 17.7%, PWS is 7.3%, PRISS is 23.4%, and all 3signs are present in 4.4% hips. Radiographs with only COS were 46 hips and the mean crossover ratio is 18.61%; while mean crossover ratio in 33 hips with all 3 sign positive was 21.95% which is statistically high. Conclusion: Thus Higher crossover ratio is associated with PRISS and PWS positive hips. Higher values of crossover ratio is associated with PRISS sign.