A custom-made guide for femoral component positioning in hip resurfacing arthroplasty: development and validation study

In the field of hip resurfacing arthroplasty, accurate femoral component placement is important to achieving a positive outcome and implant survival in both the short and long term. In this study, femoral component placement was defined preoperatively using virtual computed tomography-based surgical simulation of a classical posterior surgical approach. Custom-made surgical drill guides were produced to reproduce the surgical plan in the operating room. We first developed a custom-made guide for guide-wire placement to position the femoral resurfacing component. Then, to assess the accuracy in vivo, the custom-made guide was evaluated in five patients with normal anatomy. The first hypothesis of this patient study was that the use of custom-made neck guides would allow for an average accuracy within the range of +/- 4 degrees for the drill path and +/- 4 mm for the entry point of the guide-wire. A second hypothesis was that three-dimensional preoperative planning would enable the prediction of an implant size differing by a maximum of one size from the size eventually implanted. The presented hip resurfacing guide performed well in terms of fit, stability and accuracy. The in vivo accuracy study revealed an accuracy of 4.05 +/- 1.84 degrees for the drill path and 2.73 +/- 1.97mm for the entry point of the guide-wire. The predicted component sizes and the implanted component sizes differed maximally by one size, confirming our hypothesis. We conclude that these preliminary data are promising, but require further validation in a full clinical setting in larger patient groups