ICSV26

Implants are routinely employed in orthopaedic and dental surgeries. However, risks of failure, which are difficult to anticipate, are still experienced and may have dramatic consequences. Failures are due to degraded bone remodeling at the bone-implant interface, a multiscale phenomenon which remains poorly understood. Implant stability is a key determinant for the surgical success and is determined by the quantity and biomechanical quality of bone tissue around the implant. The primary stability occurs at the moment of implant surgical insertion within bone tissue, while secondary stability is obtained through osseointegration process, a complex multiscale phenomenon, which strongly depends on primary implant stability. The objective of this presentation is to show how acoustical methods may be used in order to provide a better understanding of the multiscale mechanisms at work at the bone-implant interface. Moreover, we will show how acoustical techniques can be used to retrieve the primary and secondary stability of different implants. The first part of this presentation will describe a methodology combining experimental surgery and a multimodality approach. A dedicated coin-shaped implant model is used and has the advantage of providing reproducible and standardized conditions. We will show how quantitative ultrasound may be used to retrieve information on the evolution of the periprosthetic bone biomechanical properties.The second part of this presentation will focus on the development of non-invasive acoustical methods that may be used to retrieve implants stability. The first set-up uses quantitative ultrasound in order to assess dental implant primary and secondary stability. The second device consists in an impact hammer equipped with a piezoelectric sensor that allows to retrieve the primary stability of implants used in total hip replacement. The validation of both approaches has been done in vitro, in silico and in vivo.