The accuracy of image-free computer navigation in the placement of the femoral component of the Birmingham Hip Resurfacing: a cadaver study.

A cadaver study using six pairs of lower limbs was conducted to investigate the accuracy of computer navigation and standard instrumentation for the placement of the Birmingham Hip Resurfacing femoral component. The aim was to place all the femoral components with a stem-shaft angle of 135 degrees . The mean stem-shaft angle obtained in the standard instrumentation group was 127.7 degrees (120 degrees to 132 degrees ), compared with 133.3 degrees (131 degrees to 139 degrees ) in the computer navigation group (p = 0.03). The scatter obtained with computer-assisted navigation was approximately half that found using the conventional jig. Computer navigation was more accurate and more consistent in its placement of the femoral component than standard instrumentation. We suggest that image-free computer-assisted navigation may have an application in aligning the femoral component during hip resurfacing.