Effects of stem design and pre-cooling prostheses on the heat generated by bone cement in an in vitro model

The necrotizing effects of the heat, particularly at more than 50 degrees C, produced by the exothermic polymerization process associated with the acrylic implant cement polymethylmethacrylate (PMMA) are well documented. The temperature changes that occur are dependent on the thickness of the PMMA. The current study investigates the hypothesis that the heat produced by the bone cement may be reduced by the choice of stem design and by pre-cooling the hip prosthesis. The thermal alterations at the bone-cement interface were measured in an in vitro model. The results indicated that a temperature decrease of approximately 7 degrees C could be achieved by pre-cooling the prosthesis, and by changing the shape of the prosthesis stem from flat and wide to round.