Femoral bone blood flow after reaming and intramedullary canal preparation - A canine study using laser Doppler flowmetry

This study was conducted to determine the effect of intramedullary reaming and canal preparation on bone blood now in the proximal femur. Thirty-five adult dogs were randomly assigned to have their intramedullary canals prepared after reaming in the following manner: group 1, ream only; group 2, lavage; group 3, methylmethacrylate cement introduction; group 4, cement pressurization after placing a cement restrictor; group 5, lavage then cement introduction; and group 6, lavage then cement pressurization. Bone blood now was measured at both metaphyseal and diaphyseal sites by using laser Doppler flowmetry before reaming, after reaming, after lavage, after cementing, and at 6 weeks after the procedure just before euthanasia. Reaming significantly decreased bone blood flow in the diaphysis (P =.046) but not in the metaphysis. Cement introduction and cement pressurization both significantly decreased bone blood now in the metaphysis (P =.035, P =.004) and diaphysis (P =.007, P =.029). Pressurization of cement had a significantly greater relative effect than cement introduction alone in the diaphysis (P =.006) but not in the metaphysis. Lavage had no effect on bone perfusion. Bone blood flow was significantly increased at 6 weeks after the initial procedure in both the metaphysis (P =.049) and the diaphysis (P =.004). The results suggest that reaming decreases diaphyseal cortical but not metaphyseal bone blood flow significantly, whereas lavage has no effect. Cement introduction with or without pressurization has a significant detrimental effect on metaphyseal and diaphyseal blood now. These findings have implications for intramedullary nailing and for canal preparation when performing arthroplasty.