Acoustic test on hip prosthesis models using Frequency Resonance Monitoring (FRM)

In this study with tests A to B3 we now have determined sound patterns in bovine and human cadaver bone. The B3 experiment measured the sound behaviour of prosthesis in cow bone with an intact cement mantel in comparison with a loose-cemented prosthesis (hroken cement mantel) in the soft tissue simulator. The frequency measurements were performed with a special microphone, which could accurately detect very low frequencies and minor vibrations. According to our study protocols FRM was used in different sets of experiments (experiments A-B): Experiment A: In this experiment the sound behaviour of cow bone (femur with distal condyles) in a soft tissue simulator was measured as well as the sound behaviour of the combination of a loose prosthesis in cow bone. Experiments B: In this set of experiments the cow bone with different types of prostheses, i.e. the sound behaviour of different types of fixation with different stabilities of the implant were tested. The possible scenarios of loose and secure prostheses were observed. High frequencies of the spectrum were hardly observed. However, a closer look at the more common lower frequencies shows a specific bone pattern.