title: Calculating the hip center of rotation using contralateral pelvic anatomy.
abstract: Failure to place an artificial hip in the optimal center of rotation results in poor hip function and costly complications. The aim of this study was to develop robust methodology to estimate hip center of rotation (hCoR) from preoperative computed tomography (CT) scans, using contralateral anatomy, in patients with unilateral diseased hips. Ten patients (five male, five female) with normal pelvic anatomy, and one patient with a unilateral dysplastic acetabulum were recruited from the London Implant Retrieval center image bank. 3D models of each pelvis were generated using commercial software. Two methods for estimation of hCoR were compared. Method 1 used a mirroring technique alone. Method 2 utilized mirroring and automatic alignment. Predicted versus actual hCoR co-ordinates were compared using intraclass correlation coefficients and paired T-tests. Both methods predicted hCoR with excellent agreement to original co-ordinates (>0.9) in all axes. Both techniques allowed prediction of the hCoR within ± 5 mm in all axes. Both techniques provided useful clinical information for planning acetabular reconstruction in patients with unilateral defects. Method 1 was less complex and is suitable for patients with developmental and degenerative pathologies. Method 2 may provide greater accuracy in a discrete group of patients with normal development prior to pathology (e.g., acetabular fractures). © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1077-1083, 2016.
authors.affiliation: Institute of Orthopaedic and Musculoskeletal Science, University College London, London, United Kingdom.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Durand-Hill
authors.affiliation: Institute of Orthopaedic and Musculoskeletal Science, University College London, London, United Kingdom.
authors.forename: Johann
authors.initials: J
authors.lastname: Henckel
authors.affiliation: Institute of Orthopaedic and Musculoskeletal Science, University College London, London, United Kingdom.
authors.forename: Keshthra
authors.initials: K
authors.lastname: Satchithananda
authors.affiliation: Institute of Orthopaedic and Musculoskeletal Science, University College London, London, United Kingdom.
authors.forename: Shiraz
authors.initials: S
authors.lastname: Sabah
authors.affiliation: Institute of Orthopaedic and Musculoskeletal Science, University College London, London, United Kingdom.
authors.forename: Jia
authors.initials: J
authors.lastname: Hua
authors.affiliation: Institute of Orthopaedic and Musculoskeletal Science, University College London, London, United Kingdom.
authors.forename: Harry
authors.initials: H
authors.lastname: Hothi
authors.affiliation: The Hillingdon Hospital NHS Foundation Trust, London, United Kingdom.
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Langstaff
authors.affiliation: Institute of Orthopaedic and Musculoskeletal Science, University College London, London, United Kingdom.
authors.forename: John
authors.initials: J
authors.lastname: Skinner
authors.affiliation: Institute of Orthopaedic and Musculoskeletal Science, University College London, London, United Kingdom.
authors.forename: Alister
authors.initials: A
authors.lastname: Hart
mesh_terms: D019644:Arthroplasty, Replacement, Hip; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D014057:Tomography, X-Ray Computed
keywords: center of rotation; computed tomography; hip arthroplasty; preoperative planning