[Comparison of total hip replacements cup orientation and position. Navigation vs. conventional manual implantation of hip prostheses].
BACKGROUND
Aim of this in-vitro study was to compare the hip cup placement for total hip replacement when using different navigation systems compared with the traditional, non-navigated technique.


METHODS
Five different navigation systems were used: the CT-less systems Navitrack, Orthopilot and Surgetics Station, as well as the CT-based Navitrack and VectorVision. Three different surgeons carried out five cup implantations using all navigation systems and the manual approach on a surgery dummy. Cup orientation (inclination and anteversion) and the cup position (achieved cup center) were determined with a coordinate measuring machine.


RESULTS
In the manual group the variability of the cup orientation was higher in comparison and hardly influenced by the surgeon. Navigation was identified as a significant factor for smaller deviations from planned inclination and anteversion angles (p<0,001 for both). Cup position was not affected by surgeon in the manual group (p=0,966). Compared with manual technique, the cup misplacement vector was significantly smaller in the CT-Navitrack group (p<0,001) but higher in the Navitrack (CT-less) and VectorVision group (p<0,001).


CONCLUSIONS
The use of computer navigation will help the surgeon to orientate the acetabular component more accurately but not necessarily with regard to cup positioning.
Honl
M
M
Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL 60612, USA. matthias_honl@rush.edu
Schwieger
K
K
Gauck
C H
CH
Lampe
F
F
Morlock
M M
MM
Wimmer
M A
MA
Hille
E
E
D000077:Acetabulum / Q000473:pathology / Q000601:surgery; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation* / Q000379:methods*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D012371:Robotics / Q000295:instrumentation* / Q000379:methods; D025321:Surgery, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D016896:Treatment Outcome