Knee replacement operations usually involve reaming the intramedullary canal of the femur bone and the insertion of an intramedullary device (e.g., nail or stem). The effect of reaming velocity on the pressure distribution within the bone was investigated numerically by solving the full three-dimensional momentum, equations together with the continuity equation, using the finite element technique. Viscosity was also varied to obtain a pressure envelope. It was found that all the experimental data follow the same trends as the envelopes predicted by the finite element model. It was clear that an increase in either the insertion reaming rate or the viscosity resulted in an increase in pressure in the intramedullary canal. Furthermore, the effect of hammering an intramedullary nail/stem was also studied. The permeability was varied in order to establish a pressure envelope. It was found that all experimental data follow the same trend obtained by the numerical model.