Experimental investigation on a novel osseointegrated implant stability assessment using on vibration analysis

Osseointegrated prostheses are widely used as the treatment for femur amputation. However, this technique requires sufficient implant stability before and during the rehabilitation period to mitigate the risk of implant breakage and loosening. Hence, reliable assessment methods for the osseointegration process are essential to ensure initial and long-term implant stability. This paper aims to investigate a vibration analysis method with a novel implant design, which focuses on the analysis of the dynamic response of the femur-implant system during the simulated osseointegration process. The paper also proposes a concept of using normalized energy difference to formulate an energy index (E-index). A 133mm-long amputated artificial femur model was constrained at the proximal end with a customized clamp. The epoxy adhesives were applied at the interface between the aforementioned femur and implant to simulate the change in stiffness in mimicking the osseointegration process. A two-unidirectionalsensor setup attached to the bottom of the implant was used to record the dynamic response stimulated by an impact hammer. The results show a significant change in magnitude of the cross-spectrum during the osseointegration processes. The resonance modes in cross-spectrum for the frequency above 1000Hz are hard to distinguish suggested that the vibration of the system being hindered by the high dampening effect of the adhesive before the initial bonding of the adhesive at 300s. The plot of E-index shows a clear correlation that the E-index provided a potential quantitative approach for monitoring the stages of osseointegration. These findings highlight the feasibility of using the vibration analysis technique and E-index to quantitatively monitor the osseointegration process for future improvement on the efficiency of human health monitoring and patient rehabilitation.