The contaminated skin-knife--fact or fiction.

Three hundred and fifty-eight patients undergoing clean orthopaedic surgery were included in this prospective study. The knives used during surgery, i.e. the knife used for skin incision (the skin-knife) and the knife used to finish the operation were bacteriologically examined. We found no evidence that the practise of discarding the knife after skin incision reduced the incidence of wound infection after clean orthopaedic surgery. Laminar air flow significantly reduced the rate of knife contamination.