The reliability of postural X-rays in measuring pelvic obliquity

Objective: To assess the interrater and intrarater reliability of two methods of measurement of postural radiographs for determining the amount of pelvic obliquity. Design: Four blinded raters evaluated the amount of pelvic obliquity using two measurement methods. Setting: Physical medicine and rehabilitation outpatient clinic in a VA hospital. Participants: Fifty-two randomly chosen radiographs from 36 patients referred to a clinic to evaluate and treat pelvic obliquity. Measures: Amount of pelvic obliquity was determined by line of eburnation and by the intersulcate line. Pearson's correlation coefficients and percent a,agreements were calculated for each set of measurements. Results: Pearson's correlation coefficients and percent agreements were higher for both interrater and intrarater measurements for the intersulcate line. Conclusion: Intersulcate line is the more reliable method for determining the amount of pelvic obliquity and will be used in future studies to assess the effectiveness of correcting pelvic obliquity to improve chronic back pain.