Abstract
BACKGROUND AND OBJECTIVES: Polymethylmethacrylate (PMMA) bone cement remains a very important part of implant fixation in joint arthroplasty. Surgeons must find a way to balance the working time with the risk of excessive heat generated through polymerization that may contribute to thermal necrosis at the cement-bone interface. Handling and heat generation depend on the temperature of the cement components and the surrounding environment. This bench study examined component prechilling and ambient temperature in two arthroplasty cement formulations. METHODS: Sixteen batches of Simplex P (Stryker Corporation, Kalamazoo, MI, USA) and 16 batches of an antibiotic-loaded Simplex formulation were evaluated in a 2 × 2 temperature design: components conditioned at 21 °C or 4 °C and specimens cured at ambient temperatures of 21 °C or 16 °C. Cement was mixed manually for 30 s and formed into two 2-cm cylinders per batch. The recorded endpoints were an operational working-time measure, indentation-defined hardening time, and peak core temperature. RESULTS: With Simplex P, prechilling at an ambient temperature of 21 °C increased mean working time from 210.4 to 315.6 s and hardening time from 645.2 to 912.8 s, while peak temperature decreased from 78.4 to 62.1 °C. The combined 4 °C component and 16 °C ambient condition produced a working time of 398.1 s, a hardening time of 1054.3 s, and a peak temperature of 60.4 °C. Corresponding values for antibiotic-loaded Simplex were 228.1 s, 682.4 s, and 76.2 °C under baseline conditions and 418.5 s, 1098.6 s, and 59.1 °C under the combined-cold condition. CONCLUSIONS: Lower component and ambient temperatures prolonged the handling and hardening intervals and reduced peak core temperatures in this bench model. Component temperature produced larger descriptive changes than the 5 °C difference in ambient temperature. The completed factorial ANOVA confirmed significant main effects for component temperature, ambient temperature, and formulation without significant interaction effects. Lower component and ambient temperatures prolonged handling and hardening intervals and reduced peak core temperatures in this exploratory bench model. However, given the small sample size, non-randomized testing sequence, subjective handling endpoint, and simplified cylinder geometry, these findings do not establish a clinical cooling protocol. Clinical recommendations require further confirmation using verified commercial products, clinically representative cement geometries, and direct interface-temperature measurements.