Porous orthopedic steel implant as an antibiotic eluting device: prevention of post-surgical infection on an ovine model.

Traumatology and orthopedic surgery can benefit from the use of efficient local antibiotic-eluting systems to avoid bacterial contamination of implanted materials. In this work a new percutaneous porous-wall hollow implant was successfully used as a local antibiotic-eluting device both in vitro and in vivo. The implant is a macroporous 316 L stainless steel filter tube with a nominal filtration cut-off size of 200 nm with one open end which was used to load the synthetic antibiotic linezolid and an opposite blind end. The antibiotic release kinetics from the device on a simulated biological fluid under in vitro conditions demonstrated an increased concentration during the first five days that subsequently was sustained for at least seven days, showing a kinetic close to a zero order release. Antibiotic-loaded implants were placed in the tibia of four sheep which were trans-surgically experimentally infected with a biofilm forming strain of Staphylococcus aureus. After 7 and 9 days post infection, sheep did not show any evidence of infection as demonstrated by clinical, pathological and microbiological findings. These results demonstrate the capability of such an antibiotic-loaded implant to prevent infection in orthopedic devices in vivo. Further research is needed to assess its possible use in traumatology and orthopedic surgery.