Does cement curing cause concerning increase of the temperature when delivered in the human humerus?

For the treatment of humeral fractures, numerous strategies exist to improve the clinical outcome of the reconstruction and to reduce the incidence of fixation failure. Injection of acrylic-based cements to reinforce the bone and/or augment the screws is one option. The heat generated during cement polymerization raises some concerns, as it could cause tissue damage. The first aim of this study was to measure the temperature over time during polymerization when acrylic cements are delivered inside the bone to treat fracture. The second aim was to assess if the ISO-5833:2002 standard can predict what happens in a real bone. Different tests were performed using two acrylic-based cements (Mendec and Cal-Cemex): (i) the ISO-5833:2002 standard (Annex C); (ii) tests on human bones (humeral diaphysis and humeral head) injected with cement to simulate fracture treatment. In the humeri, the highest temperature was measured in the diaphysis (68.6 °C for Mendec, 62.7°C for Cal-Cemex). These values are comparable with the temperature reached in other consolidated applications (vertebroplasty). Exposure to high temperature was shorter for the diaphysis than for the head. For both cements, in both the diaphysis and the head, temperatures exceeded 48°C for less than 10min. This is within the threshold for tissue necrosis. The ISO-5833:2002 yielded significantly different results in terms of maximum temperature (difference exceeding 15°C) and exposure to temperature above 48°C and 45°C. This discrepancy is probably due to a combination of factors affecting the amount of heat produced and dissipated (e.g., amount and shape of the cement, thermal conductivity).