Genauigkeit eines bildfreien Navigationssystemes für die Hüftpfannenimplantation – eine anatomische Studie

The position of the acetabular cup is of decisive importance for.
the function of a total hip replacement (THR). Using the
conventional surgical technique, correct placement of the cup often
fails due to a lack of information about pelvic tilt. With CT-based
and fluoroscopically-assisted navigation procedures the accuracy of
implantation has been significantly improved. However, additional
radiation exposure, high cost and the increased time requirement
have hampered the acceptance of these techniques. The present
anatomical study evaluates the accuracy of an alternative
procedure-image-free navigation. This method requires little extra
effort, does not substantially delay surgery, and needs no
additional imaging. Press-fit cups were implanted in 10 human
cadaveric hips with the help of the image-free navigation system,
and the position of the cups was checked intraoperatively with a
CT-based navigation system and postoperatively by computed
tomography. All cups were implanted within the targeted safe zone
with an average inclination of 44degrees (range
40degrees-48degrees, SABW 2.7degrees) and an average anteversion of
18degrees (range 12-24degrees, SABW 4.1degrees). Analysis of
accuracy of the image-free navigation software revealed only a
small, clinically tolerable deviation in cup anteversion and cup
inclination in comparison with the CT-based navigation system and
the post operative CT scans. The evaluated image-free navigation
system appears to be a practicable and reliable alternative to the
computer-assisted implantation of acetabular cups in total hip
arthroplasty.