FIXATION ELEMENT-SKIN INTERFACE CARE
There is a lack of consensus and research regarding the appropriate management of the fixation element-skin interfaces in
dogs and cats. Multiple cleansing agents have been advocated,3-8 though each has inherent benefits and faults.
Dilute chlorhexidine solutions are advocated by many surgeons.3,6 In a clinical study in people, a 0.2% chlorhexidine solution decreased fixation element tract infection compared with sterile
0.9% saline solution.9 Canine-specific studies evaluating the effects of varying concentrations of chlorhexidine diacetate on in vitro tissue samples
found concentrations of chlorhexidine greater than 0.013% to be cytotoxic to fibroblasts, though increased Staphylococcus aureus survival was noted when chlorhexidine concentrations were below 0.05%.10
A clinical study of the effects of various cleansing agents on canine wound infection rates and healing found that 0.05% chlorhexidine
solution showed greater antimicrobial effects than sterile saline solution or povidone-iodine solution, and healing of wounds
treated with 0.05% chlorhexidine solution was determined to be comparable to wounds cleansed with iodine solutions and superior
to wounds cleansed with sterile saline solution alone.11
Chlorhexidine will precipitate when diluted with saline solution; however, precipitation does not inhibit the solution's antimicrobial
effect.12 Precipitation can be prevented by diluting the chlorhexidine solution with sterile water instead of saline solution.
Some surgeons recommend povidone-iodine solutions as cleaning agents.5 Dilute iodine solutions have been found to have no benefit over sterile saline solution as a cleansing agent for fixation
element-skin interfaces in people.13 Cytotoxicity to canine fibroblasts has been documented when povidone-iodine concentrations exceed 0.5%, but concentrations
greater than 1% are necessary for antimicrobial effects against S. aureus.10 Iodophors also have diminished antimicrobial function when in contact with exudate and can cause corrosion of stainless
steel fixation pins.14
Hydrogen peroxide has been recommended by some surgeons and is economical and readily available to most owners.5,8 However, diluted hydrogen peroxide has been shown to exhibit cytotoxic effects on osteoblasts and fibroblasts even at concentration
dilutions that do not provide significant antimicrobial action.15,16
Hydrotherapy has also been recommended to help maintain cleanliness of the fixation element-skin interfaces, as well as to
decrease postoperative swelling.3,7 Hydrotherapy consists of subjecting the limb and frame to clean running water for periods of roughly 10 minutes with or
without application of an over-the-counter antimicrobial shampoo to the limb and apparatus once or twice weekly.7 Studies performed in people report statistically equivocal infection rates whether or not fixation element-skin interface
cleaning was performed when patients were allowed to shower daily.17,18 Hydrotherapy attempts to recreate a similar level of hygiene in pets.
We recommend that the owners clean the fixation element-skin interfaces daily with a 0.05% chlorhexidine solution followed
by application of a triple antibiotic (e.g. bacitracin, neomycin, and polymixin B) ointment to these sites. After the release incisions have healed, we also recommend
once or twice weekly hydrotherapy.