Femoral Component Insertion Monitoring Using Human Cadaveric Specimens

The purpose of this study is to identify a means to supplement a surgeon's tactile and auditory senses by monitoring the insertion of a tapered cementless femoral component and to identify features that indicate when the femoral component is optimally seated prior to intraoperative fracture from further impacts. This work is motivated by anecdotal evidence of an increase in fractures associated with the insertion of the component when using emerging minimally invasive surgical techniques. In this study, human cadaveric specimen femurs were prepared for a cementless femoral component by an orthopedic surgeon using standard implant-specific instrumentation. The femoral component was instrumented with accelerometers and acceleration data was obtained as the femoral component was being impacted. Acoustic measurements were also taken during impaction using a microphone. The experimental setup and protocol are explained. Results from the cadaveric femur testing are presented. Several signal processing techniques are discussed that were implemented to look for features in the data that were functions of the distance to seating. The signal processing techniques were applied to the data from this study as well as to data from a previous replicate composite femur study.