SLR - September 2018 - Jennifer Kep

Preoperative Disinfection of Foot and Ankle: Microbiological Evaluation of Two Disinfection Methods

Reference: Dingemans, S.A., Spijkerman, I.J.B., Birnie, M.F.N., Goslings, J.C., Schepers, T. Preoperative Disinfection of Foot and Ankle: Microbiological Evaluation of Two Disinfection Methods. Arch Orthop Trauma Surg. 2018 Jul 10.

Scientific Literature Review

Reviewed By: Jennifer Kep, DPM
Residency Program: St. Vincent Hospital, Worcester, MA

Podiatric Relevance: Skin preparation is essential for preoperative management and prevention of surgical site infections. It is especially important for foot and ankle procedures where there is an increase of surgical site infections compared to the rest of the body. The most frequently used substances are povidone-iodine, chlorhexidine and alcohols. The question is whether or not bathing the foot and ankle in alcohol for five minutes followed by chlorhexidine has an additive value.

Methods: Twenty-two healthy volunteers with each foot prepped in a two different manners then swab cultures taken at four different sites (subungual at hallux, first interspace, sinus tarsi and pretibial). The right foot was placed into a bag filled with 70 percent ethanol containing 10 percent IPA for five minutes then followed by painting with 0.5 percent chlorhexidine in 70 percent alcohol. The left foot was painted with 0.5 percent chlorhexidine in 70 percent alcohol. Then swab cultures taken at four sites.

Results: There were 30 positive cultures from the alcohol foot bath group and 35 from the paint-only group, which is not statistically significant. Statistically significant findings include the amount of colony forming units was lower in two sites (subungual and first interspace) in the foot bath group with alcohol; as well as number of cultures with heavy growth was lower at subungual for foot bath group.

Conclusions: In their study, they found high rates of positive cultures, even with using two substances, indicating the challenge to decontaminate the foot. Even so, a foot bath in alcohol prior to painting with chlorhexidine is an additive value in foot/ankle skin preparation as it significantly reduces the amount of bacteria in the subungual area and digital interspace. Iodine was not used in the study due to its irritant nature to the skin and appears less effective compared to chlorhexidine. In the OR, it is often difficult to prep the skin surrounding the toenail as well as digital interspaces. More often, we should consider a prescrub utilizing alcohol followed by regular skin prep.

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