title: The effect of acetabular and femoral component version on dislocation in primary total hip arthroplasty.
abstract: OBJECTIVE
  The purpose of the present study was to: (1) investigate the variation of both acetabular and femoral component version in a large series of consecutive primary THA patients, and (2) to better define the associations of acetabular and femoral component alignment and clinical factors with subsequent hip dislocation in those patients.
  
  
  METHODS
  We analyzed CT scans of 1,555 consecutive primary THAs and measured version of the components. We also documented the frequency and direction of subsequent dislocation as well as femoral head size, posterior tissue repair, any history of previous hip surgery, and gender.
  
  
  RESULTS
  The dislocation rate after THA was 3.22 %. The dislocation risk was 1.9 times higher if cup anteversion was not between 10° and 30°. Compared to hips that did not dislocate, those that experienced anterior dislocation had a significantly greater combined anteversion; those that dislocated posteriorly had a significantly smaller combined anteversion. Hips with previous rotational acetabular osteotomy or head size smaller than 28 mm correlated with an increased dislocation rate.
  
  
  CONCLUSIONS
  The dislocation risk could be higher if cup anteversion was not between 10° and 30°. Greater combined anteversion could be a risk factor of anterior dislocation, and posterior dislocation could be more common in smaller combined anteversion.
authors.affiliation: Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho Chuo-Ku, Kobe, Hyogo, 650-0017, Japan. taka2446@yg8.so-net.ne.jp.|Department of Orthopaedic Surgery and Joint Surgery Center, Takatsuki General Hospital, 1-3-13 Kosobe-Cho, Takatsuki, Osaka, 569-1192, Japan. taka2446@yg8.so-net.ne.jp.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Fujishiro
authors.affiliation: Department of Orthopaedic Surgery and Joint Surgery Center, Takatsuki General Hospital, 1-3-13 Kosobe-Cho, Takatsuki, Osaka, 569-1192, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Hiranaka
authors.affiliation: Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho Chuo-Ku, Kobe, Hyogo, 650-0017, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Hashimoto
authors.affiliation: Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho Chuo-Ku, Kobe, Hyogo, 650-0017, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Hayashi
authors.affiliation: Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho Chuo-Ku, Kobe, Hyogo, 650-0017, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kurosaka
authors.affiliation: Department of Orthopaedic Surgery, Eniwa Hospital, 2-1-1 Kogane Chuo, Eniwa, Hokkaido, 061-1449, Japan.
authors.forename: Taiki
authors.initials: T
authors.lastname: Kanno
authors.affiliation: Department of Orthopaedic Surgery, Eniwa Hospital, 2-1-1 Kogane Chuo, Eniwa, Hokkaido, 061-1449, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Masuda
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D005260:Female; D006617:Hip Dislocation / Q000209:etiology / Q000601:surgery*; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D012042:Registries; D012307:Risk Factors; D014057:Tomography, X-Ray Computed
keywords: Component version; Computed tomography; Dislocation; Total hip arthroplasty