title: Measurement of acetabular erosion. The effect of pelvic rotation on common landmarks.
abstract: Using dried bones which could be tilted and rotated, we assessed the accuracy of published radiographic methods for measuring the migration of prosthetic acetabular components and compared the results with a new method. The new line linking acetabular margins was significantly more accurate for proximal migration than the teardrop, the sacroiliac line or the sacroiliac-symphysis line. For medial migration, a new line tangential to the brim and through the horizontal mid-point of the obturator foramen was more accurate than Köhler's line, the ilio-ischial line or the iliopubic line. In combination, the two new lines can give a more accurate assessment of acetabular erosion than previous methods, since they are less affected by the differences in rotation commonly found in a series of radiographs.
authors.affiliation: Orthopaedic Academic Unit, Rayne Institute, St. Thomas' Hospital, London, England.
authors.forename: R G
authors.initials: RG
authors.lastname: Wetherell
authors.forename: A A
authors.initials: AA
authors.lastname: Amis
authors.forename: F W
authors.initials: FW
authors.lastname: Heatley
mesh_terms: D000077:Acetabulum / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000473:pathology; D001699:Biometry / Q000379:methods*; D006801:Humans; D010384:Pelvic Bones / Q000502:physiology; D011859:Radiography; D012399:Rotation