Reliability of radiographic signs for acetabular retroversion

Abstract

Acetabular retroversion may contribute to femoroacetabular impingement and lead to osteoarthritis of the hip. Retroversion has been measured on computed tomography scans. In recent years, assessment of acetabular version on anteroposterior pelvic views has gained increasing attention. We therefore aimed to determine the reliability of radiographic signs of acetabular retroversion and its association with the rater's experience. Five orthopedic surgeons (o1 to o5) rated the crossover sign, ischial spine sign and posterior wall sign on X-rays of 40 hip joints. Also, we determined the rater's experience in recognizing acetabular retroversion with a questionnaire and correlated intraobserver reliability to the calculated experience score. The intraobserver results were 0.325 (o1), 0.848 (o2), 0.684 (o3), 0.701 (o4), and 1.000 (o5) for the crossover sign, 0.750 (o1), 0.890 (o2), 0.593 (o3), 0.483 (o4), and 0.946 (o5) for the posterior wall sign; and 0.578 (o1), 0.680 (o2), 0.595 (o3), 0.375 (o4), and 0.800 (o5) for the ischial spine sign. Interobserver reliability was 0.514 for the crossover, 0.633 for the posterior, and 0.543 for the ischial spine sign wall. The experience sum score correlated to the kappa results for the crossover (r = 0.527), posterior wall (r = 0.738), and ischial spine sign (r = 0.949). Assessing acetabular version on plain radiographs is subject to intra- and interindividual error and related to the observer's individual experience.

Prevalence of Radiographic Findings Thought to Be Associated with Femoroacetabular Impingement in a Population-based Cohort of 2081 Healthy Young Adults

“…We found high agreement both within and between observers for the reliability for most of the fi ndings, which is in accordance with data in studies by others ( 17,33 ). Jamali and colleagues ( 17 ) report on k values between 0.6 and 0.7 for both intra-and interobserver studies for the COS. Kappe and colleagues ( 33 ) report on the reliability of radiographic signs for acetabular retroversion, with k results for the COS ( r = 0.53) and the posterior wall sign ( r = 0.74).…”

New Developments in Hip Imaging

“…The crossover and posterior wall signs seem to be associated with progression of osteoarthritis of the hip (88). All three signs are subject to intra-and interindividual error, as a recent report has confirmed (89): Only the posterior wall sign had a substantial interindividual agreement with a k value of 0.633. The crossover sign had the least intra-and interobserver reliability.…”

Hip Imaging in Athletes: Sports Imaging Series

“…On radiographs, three signs can help to detect acetabular retroversion: the crossover sign, the posterior wall sign, and the ischial spine sign (72). However, these signs are prone to intra-and interrater variability (73) and are susceptible to pelvic rotation and tilt on radiographs (74). One method to measure the acetabular version on transverse MR images is at the level of the acetabular roof as the angle between the line connecting the anterior and posterior acetabular rim and a vertical line (sagittal plane) (75).…”