Abstract
In cementless hip replacement surgery, the evaluation of the optimal stem implantation into the femur is
subjectively determined by the surgeon. A sufficient fixation force can be obtained by firmly inserting the implant with strong force; however, excess force may cause a femoral fracture. We know empirically that the sound changes as it stabilizes, which has helped to evaluate the appropriateness of implant fixation. We are currently adjusting stem implantation depth with the aid of the change in “impact sound” generated at the time of stem insertion. We have evaluated this impact sound subjectively and used it as information for making intraoperative decisions. The impact sound includes sound of a hammer in addition to the stem and femur. Eliminating the sound of the hammer will improve the accuracy of the evaluation of implant fixation by the impact sound. In this study, we develop tapping hammer that meet our objectives.
