Primary total knee replacement: is suction a portal of infection?

Pulsed lavage during a total knee replacement usually leaves a pool of fluid on the surgical drapes. It is common practice to suck away this fluid using the same suction device used intra-operatively. This could be a cause of direct wound contamination. We hypothesised that bacteria contaminate fluid that collects around the foot in total knee replacement surgery and that suction equipment could be a portal of contamination. We also hypothesised that bacterial count in the fluid is lower if chlorhexidine, rather than saline, is used in the pulsed lavage.

Forty patients undergoing primary total knee replacement were divided into two groups. The first group had pulsed lavage with normal saline and the second with 0.05% chlorhexidine.

At the end of the operation, 20 ml of fluid, pooled on the surgical drapes was aspirated and cultured for bacterial growth. None of the fluid samples showed bacterial growth.

Suction device used peri-operatively during knee replacement is unlikely to be a cause of wound contamination. Pulsed lavage with normal saline is as effective as lavage with chlorhexidine.