title: Dilemmas in imaging for peri-acetabular osteotomy: the influence of patient position and imaging technique on the radiological features of hip dysplasia.
abstract: Peri-acetabular osteotomy is an established surgical treatment for symptomatic acetabular dysplasia in young adults. An anteroposterior radiograph of the pelvis is commonly used to assess the extent of dysplasia as well as to assess post-operative correction. Radiological prognostic factors include the lateral centre-edge angle, acetabular index, extrusion index and the acetabular version. Standing causes a change in the pelvis tilt which can alter certain radiological measurements relative to the supine position. This article discusses the radiological indices used to assess dysplasia and reviews the effects of patient positioning on these indices with a focus on assessment for a peri-acetabular osteotomy. Intra-operatively, fluoroscopy is commonly used and the implications of using fluoroscopy as a modality to assess the various radiological indices along with the effects of using an anteroposterior or posteroanterior fluoroscopic view are examined. Each of these techniques gives rise to a slightly different image of the pelvis as the final image is sensitive to the position of the pelvis and the projection of the x-ray beam.
authors.affiliation: Centre for Orthopaedic and Trauma Research, The University of Adelaide and Royal Adelaide Hospital, Department of Orthopaedics and Trauma, Level 4 Bice Building, RAH, North Terrace, Adelaide, SA 5000, Australia.
authors.forename: D
authors.initials: D
authors.lastname: Kosuge
authors.affiliation: Centre for Orthopaedic and Trauma Research, The University of Adelaide and Royal Adelaide Hospital, Department of Orthopaedics and Trauma, Level 4 Bice Building, RAH, North Terrace, Adelaide, SA 5000, Australia.
authors.forename: T
authors.initials: T
authors.lastname: Cordier
authors.affiliation: Centre for Orthopaedic and Trauma Research, The University of Adelaide and Royal Adelaide Hospital, Department of Orthopaedics and Trauma, Level 4 Bice Building, RAH, North Terrace, Adelaide, SA 5000, Australia.
authors.forename: L B
authors.initials: LB
authors.lastname: Solomon
authors.affiliation: Centre for Orthopaedic and Trauma Research, The University of Adelaide and Royal Adelaide Hospital, Department of Orthopaedics and Trauma, Level 4 Bice Building, RAH, North Terrace, Adelaide, SA 5000, Australia.
authors.forename: D W
authors.initials: DW
authors.lastname: Howie
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging* / Q000601:surgery; D005471:Fluoroscopy; D006618:Hip Dislocation, Congenital / Q000000981:diagnostic imaging* / Q000601:surgery; D006621:Hip Joint / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D010027:Osteotomy / Q000379:methods; D056888:Patient Positioning; D016683:Supine Position; D016896:Treatment Outcome; D055815:Young Adult
keywords: Peri-acetabular osteotomy; PAO; Imaging; Pelvis tilt; Fluoroscopy