Changing knives a wasteful and unnecessary ritual.

The use of two knives for making a surgical incision is a deeply ingrained practice of British surgery and a postal survey of the theatre superintendents in the South-West Thames Region revealed that out of 143 surgeons all but one use this technique. Therefore we undertook a bacteriological study of the knife blades used on a general surgical unit. This showed that under normal conditions pathogenic organisms do not contaminate the knife blade and are not carried into the wound by it. The use of only one knife to make an incision does not increase the incidence of wound infection. A survey of the world literature confirms these findings. The wasteful and unnecessary ritual of using two knives to make an incision through normal skin has no theoretical, scientific or clinical basis and can be discontinued.