title: Change in Pelvic Sagittal Inclination From Supine to Standing Position Before Hip Arthroplasty.
abstract: Cup anteversion and inclination are important for avoiding implant impingement and dislocation in total hip arthroplasty. However, functional cup anteversion and cup inclination also change as the pelvic sagittal inclination (PSI) changes. Therefore, PSI in both supine and standing positions was measured in a large cohort in this study.
  
  
  
  A total of 422 patients (median age, 61; range, 15-87) who underwent total hip arthroplasty were the subjects of this study. There were 83 patients with primary osteoarthritis (OA), 274 patients with developmental dysplasia-derived secondary OA, 48 patients with osteonecrosis, and 17 patients with rapidly destructive coxopathy (RDC). Preoperative PSI in supine and standing positions was measured by automated computed topography segmentation and landmark localization of the pelvis followed by intensity-based 2D-3D registration, and the number of cases in which PSI changed more than 10° posteriorly was calculated. Hip disease, sex, and age were analyzed if they were related to a PSI change of more than 10°.
  
  
  
  The median PSI was 5.1° (interquartile range, 0.4°-9.4°) in supine and -1.3° (interquartile range, -6.5° to 4.2°) in standing position. There were 79 cases (19%) in which the PSI changed more than 10° posteriorly from supine to standing. Elder age and patients with primary OA and RDC were revealed to be the related factors.
  
  
  
  PSI changed more than 10° posteriorly from supine to standing in 19% of cases. Age and diagnosis of primary OA and RDC were the significant factors for the posterior rotation.
authors.affiliation: Department of Orthopaedic Medical Engineering, Osaka University Graduate School of Medicine, Suita City, Osaka, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Uemura
authors.affiliation: Department of Orthopaedic Medical Engineering, Osaka University Graduate School of Medicine, Suita City, Osaka, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Takao
authors.affiliation: Imaging-based Computational Biomedicine Lab, Nara Institute of Science and Technology, Ikoma City, Nara, Japan.
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Otake
authors.affiliation: Imaging-based Computational Biomedicine Lab, Nara Institute of Science and Technology, Ikoma City, Nara, Japan.
authors.forename: Koki
authors.initials: K
authors.lastname: Koyama
authors.affiliation: Imaging-based Computational Biomedicine Lab, Nara Institute of Science and Technology, Ikoma City, Nara, Japan.
authors.forename: Futoshi
authors.initials: F
authors.lastname: Yokota
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Suita City, Osaka, Japan.
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Hamada
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Suita City, Osaka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Sakai
authors.affiliation: Imaging-based Computational Biomedicine Lab, Nara Institute of Science and Technology, Ikoma City, Nara, Japan.
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Sato
authors.affiliation: Department of Orthopaedic Medical Engineering, Osaka University Graduate School of Medicine, Suita City, Osaka, Japan.
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Sugano
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000601:surgery; D010020:Osteonecrosis / Q000601:surgery; D010384:Pelvic Bones / Q000000981:diagnostic imaging / Q000502:physiology*; D010388:Pelvis; D011187:Posture; D012399:Rotation; D016683:Supine Position; D055815:Young Adult
keywords: automatic measurement; hip; pelvic sagittal inclination; standing position; supine position; total hip arthroplasty