In Vivo Murine Model of Continuous Intramedullary Infusion of Particles-A Preliminary Study

Continued production of wear debris affects both initial osseointegration and subsequent bone remodeling of total joint replacements (TJRs). However, continuous delivery of clinically relevant particles using a viable, cost effective, quantitative animal model to simulate the scenario in humans has been a challenge for orthopedic researchers. In this study, we successfully infused blue-dyed polystyrene particles, similar in size to wear debris in humans, to the intramedullary space of the mouse femur for 4 weeks using an osmotic pump. Approximately 40% of the original particle load (85 mu L) was delivered into the intramedullary space, an estimate of 3 X 109 particles. The visible blue dye carried by the particles confirmed the delivery. This model demonstrated that continuous infusion of particles to the murine bone-implant interface is possible. In vivo biological processes associated using wear debris particles can be studied using this new animal model. (C) 2008 Wiley Periodicals. Inc. J Biomed Mater Res Part B: Appl Biomater 88B: 250-253, 2009