Introduction: The curing of polymethylmethacrylate cement is an exothermic reaction, with temperatures reaching 80oC. Thus contact with cement can result in thermal injury. During orthopaedic procedures bone cement may be inadvertently left lying on surgical drapes. This study aims to investigate the effect of drapes on the contact temperature of such cement.

Methods: The experiment was carried out in an orthopaedic theatre with a constant temperature and humidity. Polymethylmethacrylate cement was prepared and pieces of cement of a specific size were investigated. Experiment one measured the contact temperature of curing cement in isolation. Experiment two and three investigated the effect of one and two layers of surgical drape respectively on contact temperature.

Results: The mean maximum temperature reached in experiments one, two and three was 75oC, 71oC and 69oC respectively. The maximum temperature was reached quickest in experiment three. In considering the time period that the contact temperature remained above 40oC this was longest in experiment three at 750s followed by experiment 2 and then experiment 1 at 525s and 330s respectively. Contact temperature graphs for each experiment have been plotted in figure.1

Discussion: One might think that drapes provide a protective barrier between a patient’s skin and bone cement, however this is incorrect. The drapes insulate the exothermic reaction of curing bone cement which tends to accelerate the reaction. Furthermore the insulating effect of drapes causes curing bone cement to lose heat at a slower rate resulting in the contact temperature remaining above 40oC for longer; this increases the potential for thermal injury. This study demonstrates that a specific effort should be made to ensure bone cement is not inadvertently left lying on surgical drapes.