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 prior 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 postulated to transduct mechanical stress signals to bone cells via loading-dependent flow of interstitial fluid through the lacunocanalicular network of bone. Thus, an understanding and new possibilities for influencing these processes may be of great importance for implant success. An ex vivo model was developed and validated for investigation of fluid displacements in bone after endoprosthesis implantation. This model serves to explicate the effects of surgical intervention as well as mechanical loading of the implant-bone construct on load-induced fluid flow in the vicinity of the implant. Using this model, we intend to quantify perfusion and extravascular flow dynamics in the vicinity of implants and define optimal conditions for enhancing molecular transport of osteotropic agents from the implant surface to apposing bone as well as from the blood supply to the implant surface. Furthermore, the elucidation of main transport pathways may help in understanding the distribution of wear particles in bone surrounding implant, a process which has been postulated to cause osteolysis and implant loosening. Copyright 1999 Kluwer Academic Publishers