A novel ex vivo model for investigation of fluid displacements in bone after endoprosthesis implantation

Tissue perfusion and mass transport in the vicinity of implant surfaces pri or to integration or bonding may play a crucial role in modulating cellular activities associated with bone remodeling, in particular, at early stages of the integration process. Furthermore, fluid displacements have been pos tulated to transduct mechanical stress signals to bone cells via loading-de pendent flow of interstitial fluid through the lacunocanalicular network of bone. Thus, an understanding and new possibilities for influencing these p rocesses may be of great importance for implant success. An ex vivo model w as developed and validated for investigation of fluid displacements in bone after endoprosthesis implantation. This model serves to explicate the effe cts of surgical intervention as well as mechanical loading of the implant-b one construct on load-induced fluid flow in the vicinity of the implant. Us ing this model, we intend to quantify perfusion and extravascular flow dyna mics in the vicinity of implants and define optimal conditions for enhancin g molecular transport of osteotropic agents from the implant surface to app osing bone as well as from the blood supply to the implant surface. Further more, the elucidation of main transport pathways may help in understanding the distribution of wear particles in bone surrounding implant, a process w hich has been postulated to cause osteolysis and implant loosening. (C) 199 9 Kluwer Academic Publishers.