INFLUENCE OF BACTERIAL STRAINS ON BONE INFECTION

Experiments were performed on 120 rabbits to compare the probability o f infection after bone surgery without an implant, with polymethylmeth acrylate, and with bone autografts. Staphylococcus aureus phage type 9 4/96, isolated from a human osteomyelitis, was instilled into the intr amedullar cavity after reaming of the femoral canal and before inserti on of the implant. The different 50% infective doses were determined f or each of the groups for comparative purposes. The bacterial concentr ations required to produce infection in femora without an implant were two times less than those necessary in femora implanted with polymeth ylmethacrylate. The bone graft required bacterial concentrations nine times less than those necessary to infect femora containing polymethyl methacrylate and four times less than those required to infect femora without an implant. The results presented here confirm that the suscep tibility to infection in orthopaedic surgery is not only material depe ndent but also bacteria dependent.