title: Evaluation of the accuracy of femoral component orientation by the CT-based fluoro-matched navigation system.
abstract: OBJECTIVE
  Accurate orientation of acetabular and femoral components are important during THA. However, no study has assessed the use of the CT-based fluoro-matched navigation system during THA. Therefore, we have evaluated the accuracy of stem orientation by CT-based fluoro-matched navigation.
  
  
  METHODS
  The accuracy of stem orientation by CT-based fluoro-matched navigation was assessed by postoperative CT data. Furthermore, we compared the postoperative stem orientation with the intraoperative registration errors.
  
  
  RESULTS
  The average antetorsion error of the stem (navigation records - postoperative CT) was -0.5° ± 5.2°. The stem valgus error was 0.4° ± 2.7°. The accuracy of the navigation record for the orientation of the stem valgus was dependent on the intraoperative registration errors.
  
  
  CONCLUSIONS
  The clinical accuracy of CT-based fluoro-matched navigation is adequate for stem alignment orientation, and the intraoperative verification of registration errors is valuable for checking the accuracy of stem orientation by navigation.
authors.affiliation: Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan. shayashi@med.kobe-u.ac.jp
authors.forename: Shinya
authors.initials: S
authors.lastname: Hayashi
authors.forename: Takayuki
authors.initials: T
authors.lastname: Nishiyama
authors.forename: Takaaki
authors.initials: T
authors.lastname: Fujishiro
authors.forename: Shingo
authors.initials: S
authors.lastname: Hashimoto
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Kanzaki
authors.forename: Kotaro
authors.initials: K
authors.lastname: Nishida
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Kuroda
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kurosaka
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000601:surgery; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D060750:Bone Anteversion / Q000000981:diagnostic imaging; D017760:Bone Malalignment / Q000000981:diagnostic imaging / Q000517:prevention & control*; D060906:Coxa Valga / Q000000981:diagnostic imaging; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging* / Q000601:surgery; D005471:Fluoroscopy / Q000379:methods*; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000601:surgery; D006801:Humans; D008297:Male; D011184:Postoperative Period; D012189:Retrospective Studies; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*