An experimental model was designed to investigate the role of
intramedullary pressure on cardiopulmonary function and pulmonary pathology
during arthroplasty using cemented and non-cemented components. Twenty-four
dogs were divided randomly into three groups: a group that received a
non-cemented implant in which low intramedullary pressure was generated, a
group that received a cemented implant, and one that received bone wax and
an implant; high intramedullary pressures were generated in the latter two
groups. Bone wax was used to generate high intramedullary pressures without
the use of bone cement. In the group with the non-cemented implant, few
pulmonary microemboli and no significant cardiorespiratory changes were
found. In the groups that received bone wax and an implant or the cemented
implant, there were many pulmonary microemboli and significant
cardiorespiratory changes, including decreased arterial oxygen tension,
increased pulmonary arterial pressure, and increased intrapulmonary shunt
fraction. There was no evidence that methylmethacrylate monomer was
responsible for the cardiorespiratory changes in the group with the
cemented implant.