Orthopaedic procedures often involve reaming of the intramedullary canal of the long bones to facilitate the insertion of an intramedullary device. The effect of this reaming on the pressure and temperature within the bone was investigated numerically by solving the full three-dimensional momentum equations, together with the continuity equation and energy equation, using the finite element technique. It was found that once the flutes of the reamer become clogged and congealed, the rotational rate had little effect on the pressure distribution. A temperature model for the reamer head during reaming procedures, which took into account parameters of both the bone and reamer, was implemented. The numerical simulation was found to accurately mimic the thermal results obtained during experimental procedures. Viscosity variations of marrow substitutes, which are commonly used in experiments, were found to have little effect on temperture distribution.