Assessment of Bone Vibrational Transmissibility in Tibia with External Fixator

Bone fractures occur in case of excessive force or stress, and they can be treated with different osteosynthesis devices. Depending on the severity and location, they take several weeks to months to heal completely. Thus, it is crucial to determine an accurate timing for the system removal, to avoid further complications. Nowadays, the bone healing process is periodically monitored through x-rays imaging. The drawback of this method relies on the use of ionizing radiation provided to the patient and the qualitative evaluation of the bone callus state. Alternative techniques should overcome these limitations. Indeed, the aim of this study is to propose a diagnostic method based on the analysis of the transmissibility of vibrational signals. It was conducted on a phantom tibia with an external fixator used as propagation medium for vibration. Results obtained on intact and fractured tibia appear to be encouraging. The presence of the simulated fracture reduces the transmissibility of the vibrational signal. Following the healing steps from a fracture condition to an intact one, there is a rising on the transmissibility going from 0.168 (fractured tibia) to 0.528 (intact tibia). This suggests the possibility to map the transmissibility throughout the entire healing process. Indeed, an increase of vibration transmission should be observed. Future studies need to further deepen this technique by simulating the whole healing process and monitoring the state of the bone callus in patients with external fixators.