Assessing peri-implant tissue infection prevention in a percutaneous model.
BACKGROUND
Infection remains the main challenge to percutaneous, intramedullary osseointegrated implant technology. The purpose of this investigation was to determine if a broad spectrum antimicrobial, Ceragenin (CSA-13) could prevent pin track infections in a percutaneous tibial pin site in a sheep model.


METHODS
In 20 sheep, a smooth titanium alloy pin/implant was inserted percutaneously through the medial skin and both cortices of the proximal tibia. In 10 sheep, the pin/skin interface was treated with a CSA-13-embedded foam pad. Ten sheep served as controls receiving an untreated pad. At the end of 24 weeks, or if they presented with clinical signs of infection, the animals were euthanized. Histological stains were processed from soft tissue and bone, and bacterial cultures were taken from tissue, bone, and blood. In addition to clinical signs, sheep were considered infected if at least one tissue culture and/or histologically stained sample was positive.


RESULTS
Compared with the controls, CSA-13 did not prevent pin track infection (p = 0.88). Large gaps around the pin indicated a lack of skin-pin adhesion.


CONCLUSIONS
In this application, CSA-13 was not effective in preventing pin track infections. This study suggests that maintaining skin attachment, at the implant surface of osseointegrated implants, is essential as a primary barrier to infection. Local antimicrobial treatments should be considered a secondary barrier to bacterial invasion of the pin/skin interface and deeper tissues.
Perry
Emily L
EL
Bone and Joint Research Laboratory, Veterans Affairs Health Care System, Salt Lake City, Utah, USA.
Beck
J Peter
JP
Williams
Dustin L
DL
Bloebaum
Roy D
RD
D000497:Alloys; D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D000890:Anti-Infective Agents / Q000627:therapeutic use; D000891:Anti-Infective Agents, Local / Q000627:therapeutic use; D001672:Biocompatible Materials; D001846:Bone Development / Q000502:physiology; D001842:Bone and Bones / Q000382:microbiology / Q000473:pathology; D007091:Image Processing, Computer-Assisted; D053208:Kaplan-Meier Estimate; D008855:Microscopy, Electron, Scanning; D016613:Plastic Embedding; D019736:Prostheses and Implants; D011475:Prosthesis Failure; D016459:Prosthesis-Related Infections / Q000382:microbiology / Q000473:pathology / Q000517:prevention & control*; D011859:Radiography; D012756:Sheep; D013530:Surgical Wound Infection / Q000382:microbiology / Q000517:prevention & control; D013752:Tetracycline / Q000627:therapeutic use; D013977:Tibia / Q000000981:diagnostic imaging / Q000254:growth & development / Q000502:physiology; D014025:Titanium
D000497:Alloys; D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D000891:Anti-Infective Agents, Local; D001672:Biocompatible Materials; C031462:titanium alloy (TiAl6V4); D014025:Titanium; D013752:Tetracycline