title: Accuracy of navigation-assisted acetabular component positioning studied by computed tomography measurements: methods and results.
abstract: The postoperative position of the acetabular component is key for the outcome of total hip arthroplasty. Various aids have been developed to support the surgeon during implant placement. In a prospective study involving 4 centers, the computer-recorded cup alignment of 37 hip systems at the end of navigation-assisted surgery was compared with the cup angles measured on postoperative computerized tomograms. This comparison showed an average difference of 3.5 degrees (SD, 4.4 degrees ) for inclination and 6.5 degrees (SD, 7.3 degrees ) for anteversion angles. The differences in inclination correlated with the thickness of the soft tissue overlying the anterior superior iliac spine (r = 0.44; P = .007), whereas the differences in anteversion showed a correlation with the thickness of the soft tissue overlying the pubic tubercles (r = 0.52; P = .001). In centers experienced in the use of navigational tools, deviations were smaller than in units with little experience in their use.
authors.affiliation: Department of Radiology, Kaiser Franz Josef Hospital, Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Ybinger
authors.forename: W
authors.initials: W
authors.lastname: Kumpan
authors.forename: H E
authors.initials: HE
authors.lastname: Hoffart
authors.forename: B
authors.initials: B
authors.lastname: Muschalik
authors.forename: W
authors.initials: W
authors.lastname: Bullmann
authors.forename: K
authors.initials: K
authors.lastname: Zweymüller
mesh_terms: D000077:Acetabulum; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed