Abstract
Purpose:
The use of computer navigation has been shown to improve the accuracy of femoral component placement compared to conventional instrumentation in hip resurfacing. Whether exposure to computer navigation improves accuracy when the procedure is subsequently performed with conventional instrumentation without navigation has not been explored. We examinedwhether femoral component alignment utilizing a conventional jig improves following experience with the use of imageless computer navigation for hip resurfacing.
Methods:
Between December 2004 and December 2008, 213 consecutive hip resurfacings were performed by a single surgeon. The first 17 (Cohort 1) and the last 9 (Cohort 2) hip resurfacings were performed using a conventional guidewire alignment jig. In 187 cases the femoral component was implanted using the imageless computer navigation. Cohorts 1 and 2 were compared for femoral component alignment accuracy.
Results:
All components in Cohort 2 achieved the position determined by the pre-operative plan. The mean deviation of the stem-shaft angle (SSA) from the pre-operatively planned target position was 2.2 degrees (SD, 2.2°, 95% CI, 0.8°, 3.7°) in Cohort 2 and 5.6 degrees (SD, 4.3°, 95% CI, 3.6°, 7.6°) in Cohort 1 (p = 0.01). Four implants in Cohort 1 were positioned at least 10 degrees varus compared to the target SSA position and another four were retroverted.
Conclusions:
Femoral component placement utilizing conventional instrumentation may be more accurate following experience using imageless computer navigation.
