title: Combined anteversion technique reduced the dislocation in cementless total hip arthroplasty.
abstract: OBJECTIVE
  The combined anteversion (CA) technique is a method in which the cup is placed according to the stem anteversion in total hip arthroplasty (THA). We examined whether the CA technique reduced the dislocation rate, and the distribution of CA with the manual placement of the cup.
  
  
  METHODS
  We retrospectively reviewed 634 hips in 579 patients with primary cementless THA. In 230 hips using the CA technique [CA(+)], a CA of 50 ± 10° was the aim. In the remaining 404 hips [CA(-)], the cup was first placed targeting 20° of anteversion. The post-operative CA was measured using the computed tomography (CT) images in 111 hips.
  
  
  RESULTS
  One hip (0.4%) had a dislocation in the CA(+) group, whereas ten hips (2.5%) had a dislocation in the CA(-) group. A multivariate analysis showed that primary diagnosis, head size and CA technique significantly influenced the dislocation rate. Patients in the CA(-) group were 5.8 times more likely to have a dislocation compared to the CA(+) group. In the 111 hips with CT images, 81 hips (73.0%) achieved the intended CA.
  
  
  CONCLUSIONS
  Although the manual placement of the cup resulted in 27% of outliers from the intended CA, the CA technique significantly reduced the dislocation after primary THA.
authors.affiliation: Department of Orthopaedic Surgery, Kyushu University, Fukuoka, Japan, yasunaka@ortho.med.kyushu-u.ac.jp.
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Nakashima
authors.forename: Masanobu
authors.initials: M
authors.lastname: Hirata
authors.forename: Mio
authors.initials: M
authors.lastname: Akiyama
authors.forename: Takashi
authors.initials: T
authors.lastname: Itokawa
authors.forename: Takuaki
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Goro
authors.initials: G
authors.lastname: Motomura
authors.forename: Masanobu
authors.initials: M
authors.lastname: Ohishi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hamai
authors.forename: Yukihide
authors.initials: Y
authors.lastname: Iwamoto
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation / Q000379:methods*; D060750:Bone Anteversion / Q000000981:diagnostic imaging / Q000601:surgery*; D005260:Female; D006617:Hip Dislocation / Q000453:epidemiology* / Q000517:prevention & control*; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D019637:Orthopedic Procedures / Q000295:instrumentation / Q000379:methods; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
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