In this study, the major goal was to evaluate in vitro and in vivo findings by macroscopy, radiology, and histology to determine the effectiveness of
therapy of
experimental implant-related
osteomyelitis with
antibiotic carrier rods constructed of microbial
polyesters. The
polymers used were poly(3-hydroxybutyrate-co-4-hydroxyvalerate) [P(3-HB-co-4-HB)] and poly(3-hydroxybutyrate-co-3-hydroxy- valerate) [P(3-HB-co-3-HV)]. Both the
Sulperazone and the Duocid-P(3-HB-co-4-HB) rods with a
drug to
polymer ratio of 1:1 (w/w) were effective in treating the bone
infection that was experimentally initiated by inoculation of a hemolytic strain of Staphylococcus aureus (
coagulase positive; phage type 52/52b) together with
metal implants into the medullary area of rabbit tibia. Macroscopical data revealed that the effectiveness of
therapy was apparent at week 6 for all categories tested. Radiological findings with Duocid- and
Sulperazone-loaded P(3-HB-co-4-HB) rods improved significantly when judged by changes in periosteal elevation, widening of bone shaft, new bone formation, and soft-tissue deformation after 6 weeks of implantation. Histologically the signs of
infection were found to subside by weeks 3 and 6. Inflammatory cells were replaced with bone-forming cells upon treatment with Sulperazone-P(3-HB-co-4-HB) and Duocid-P(3-HB-co-4-HB). Osteoblastic activity was prominent. Intramedullary
inflammation, although still present, started to be replaced by fibrous or bony tissue. Histological findings presented the subsidence of
infection. In summary, the
antibiotic-loaded biopolymeric rods appeared to have potential as a new controlled-release system for the treatment of implant related
osteomyelitis and chronic
osteomyelitis.