title: Comparison of navigation accuracy in THA between the mini-anterior and -posterior approaches.
abstract: BACKGROUND
  The accuracy of a CT-based hip navigation might depend on surgical approaches, resulting in varying accuracy of implant alignment.
  
  
  METHODS
  We performed primary cementless total hip arthroplasty (THA) with mini-incision surgery (MIS) to 40 well-matched patients (anterior or posterior approaches, 20 hips each), using navigation with surface registration. We investigated cup alignment using postoperative computed tomography (CT) and compared the navigation accuracy between the two approaches, i.e. the difference between intra-operative and postoperative alignments of the cup.
  
  
  RESULTS
  There was no significant difference between the two approaches. The mean navigation accuracies in abduction and anteversion were 2.0 degrees (SD 1.4 degrees) and 2.7 degrees (SD 1.9 degrees), respectively, in the anterior approach, and 2.4 degrees (SD 2.0 degrees) and 2.0 degrees (SD 1.4 degrees), respectively, in the posterior approach. All cup alignments were within 10 degrees of the target orientation.
  
  
  CONCLUSIONS
  This CT-based navigation for MIS-THA provides navigation accuracy without significant differences between the two approaches and with favourable alignment of the cup.
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan. hana-osaka@umin.net
authors.forename: Takehito
authors.initials: T
authors.lastname: Hananouchi
authors.forename: Masaki
authors.initials: M
authors.lastname: Takao
authors.forename: Takashi
authors.initials: T
authors.lastname: Nishii
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Miki
authors.forename: Daiki
authors.initials: D
authors.lastname: Iwana
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshikawa
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Sugano
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000601:surgery*; D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000379:methods / Q000592:standards; D005260:Female; D006622:Hip Prosthesis / Q000592:standards*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000379:methods*; D016059:Range of Motion, Articular; D014057:Tomography, X-Ray Computed / Q000379:methods