Behavior of the different implant materials in acute infection and efficacy of antibiotherapy: experimental study in rats.

In this study, we propose a comparison of the behaviors of four different implant materials in case of acute infection: expanded polytetrafluoroethylene (e-PTFE), porous high density polyethylene (PHDPE), silicone, and autogenous cartilage tissue. The efficacy of prophylactic and therapeutic antibiotic therapies was also investigated in a rat model as four groups: group A, acute infection and no antibiotic therapy (n = 24); group B, acute infection and prophylactic antibiotic therapy (n = 24); group C, acute infection and therapeutic antibiotic therapy (n = 24); and control, no infection and no antibiotic therapy (n = 24). All materials with dimensions of approximately 1 x 1 cm(2) diameter were implanted separately under the dorsal skin of rats. Staphylococcus aureus was used as the infectious agent and antibiotic therapy was done with seftriaxone (Desefin, I.M., 20 mg/kg/day). Tissue specimens were obtained on postoperative days 14 and 21. Semiquantitative and qualitative alterations existing in the connective tissue neighboring the implant material (reaction zone-capsule tissue), fixation to the host tissue, cellular ingrowth (interstice qualitatively), and infection signs were assessed either macroscopically or microscopically. In group A, all materials were affected negatively that led to continuous regression in the wound healing process. Fixation of the cartilage to the surrounding tissue was weak compared with other groups. Fibrovascular tissue ingrowth in porous implants was delayed, and no regular capsule formation was observed around silicone implants. In group B, outcomes were similar to control groups. Porous materials showed tissue ingrowth into the pores as good as the control group. Regular capsular tissue formed around the silicone implants and cartilage tissues. In group C, where silicone had been used, wound healing was not as good as in group B and the control group. In the e-PTFE group, the granulation tissue forming through the pores did not show a good quality as the control group, and capsule formation around the material was irregular, leading to insufficient fixation. While the wound healing properties of the PHDPE group were not as good as the control group, there was no difference in terms of fixation to the wound bed. On the other hand, wound healing of the cartilage group was as satisfying as the control group.