Diagnostic Value of Ischial Spine Sign in Patients with Acetabular Retroversion

Background: Acetabular Retroversion (AR) is a hip disorder and one of the causes of pain in this area. Evaluationof positive Cross Over Sign (COS) on AP X-Rays of the hip is currently the best method of diagnosis of AR. Severalstudies have measured co-existence of Ischial Spine Sign (ISS) in patients with AR. In this study we evaluated thediagnostic value of ISS in confirmation of AR and compared it with the diagnostic value of COS.Methods: In this study, 4120 AP hip X-Rays from Akhtar Hospital, Shahid Beheshti University of Medical Sciences,Tehran, were studied. Based on radiologic criteria, 1180 X-Rays were considered as standards and evaluated for ISS,COS and PWS (Posterior Wall Sign). Data analysis was done for correlation between ISS and COS.Results: A total of 1180 out of 4120 X-Rays were considered as standard; among which, 86 were diagnosed withAR based on positive COS in presence of PWS. Both ISS and COS were positive concurrently in 69 X-Rays. ISSwas positive in absence of COS in 11 X-rays. No significant difference in diagnostic value for diagnosis of acetabularretroversion was found between ISS and COS (P<0.05).Conclusion: According to our results, both ISS and COS signs can be employed for diagnosis of AR (acetabularretroversion). Considering the absence of a significant difference between these two signs in confirmation of AR, it canbe perceived that the diagnostic value of ISS in confirmation of AR is equal to COS. Validation of the mentioned resultsrequires further studies.Level of evidence: IV