Background: The most efficient way to prepare the skin for foot and
ankle surgery is unknown. In recent studies, >70% of aerobic bacterial
cultures of specimens taken from the nail folds following skin preparation
with povidone-iodine were positive. The goal of the current study was to
determine the effect of isopropyl alcohol on the eradication of bacteria from
the nails and skin of the normal foot and ankle. In addition, the effect of
using a bristled brush rather than sponges to scrub the foot was
investigated.
Methods: Four skin-preparation techniques were studied in two sets
of twenty-five volunteers. In phase I of the study, the right foot and ankle
of each member of the first set of volunteers was prepared with method 1,
which consisted of a two-stage povidone-iodine scrub and paint with use of
soft sponges. The left foot and ankle was prepared with method 2, which
consisted of method 1 as well as an additional prewash with 70% isopropyl
alcohol. In phase II, the right foot and ankle of each member of the second
set of volunteers was prepared with method 3, which consisted of a
povidone-iodine scrub and paint with use of a bristled brush to scrub the
foot. The left side was prepared with method 4, which consisted of an alcohol
scrub and paint with use of a bristled brush to scrub the foot. At the end of
the preparation process, specimens for aerobic bacterial cultures were
obtained from the hallucal nail fold, interdigital web spaces, and anterior
aspect of the ankle. Cultures were interpreted as positive or negative, and
the results were also assessed quantitatively.
Results: The rates of positive cultures of the nail-fold specimens
were 76% and 80% after methods 1 and 2 (soft sponges) and 76% and 12% after
methods 3 and 4 (bristled brush). The reduction in the percentage of positive
cultures with method 4 was highly significant (p < 0.001). Cultures of the
specimens from the web spaces showed a significant difference in the rates of
positive results between methods 1 and 2 (36% and 8%, p < 0.05) but no
significant difference between methods 3 and 4 (12% and 0%, p = 0.25). The
rates of positive cultures of specimens from the anterior aspect of the ankle
were consistently low (=4% for all methods). Quantitative analysis of
positive cultures demonstrated significant reductions (p < 0.01) in heavy
growth when bristled brushes had been used, both with povidone-iodine and
isopropyl alcohol.
Conclusions: The use of isopropyl alcohol and the use of a bristled
brush both have beneficial effects on the skin-preparation process before foot
and ankle surgery. In the current investigation, the most effective technique
was the use of isopropyl alcohol in conjunction with scrubbing with a bristled
brush. Merely washing the foot with alcohol-soaked sponges provided limited
benefit to the web spaces only.
Level of Evidence: Therapeutic Level I. See Instructions
to Authors for a complete description of levels of evidence.