Accuracy of Navigation-Assisted Acetabular Component Positioning Studied by Computed Tomography Measurements
Thomas Ybinger; W. Kumpan; H. E. Hoffart; B. Muschalik; W. Bullmann; K. ZweymüllerHip
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° (SD, 4.4°) for inclination and 6.5° (SD, 7.3°) 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.
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