Osteomyelitis of the proximal portion of the tibia was consistently
produced in the dog by the instillation of a suspension of Staphylococcus
aureus about an intramedullary foreign body consisting of acrylic bone
cement. The clinical, histological, and roentgenographic manifestations of
the infectious process were consistent with those of subacute
osteomyelitis, such as may be encountered in infections following total
joint arthroplasty. The osteomyelitic process persisted in six of the seven
tibiae even after removal of the acrylic bone cement. Using this model,
gentamicin-impregnated acrylic bone cement (Palacos) prevented the
development of osteomyelitis in nine of ten tibiae that were concomitantly
exposed to Staphylococcus aureus in concentrations ranging from 1 x 10(3)
to 1 x 10(9) organisms. However, Palacos in bulk form was ineffective in
the treatment of three of five tibiae in which osteomyelitis caused by
Staphylococcus aureus was already established. Clinical Relevance: A
variety of new antimicrobial agents has been introduced, but evaluation of
the value of these agents in infections of the musculoskeletal system has
relied almost exclusively on clinical trials. Preclinical trials in an
animal model could permit earlier detection of promising agents and proper
dosage schedules. Newer surgical procedures utilized in the treatment of
osteomyelitis, such as local muscle flaps and free vascularized flaps,
could also be evaluated to determine how they influence the local blood
supply and microbial persistence. In addition, the animal model might aid
in the evaluation of newer and non-invasive diagnostic scanning techniques
used in the study of infection.