The effect of cement mixing time on the biomechanics of cement augmented plated fractures in canine femora.

Abstract

The goal of this study was to determine the effect of cement mixing time and, hence, cement viscosity on the biomechanical behavior of femoral fracture fixation. Cadaveric plated canine femoral fracture model, comparing treatments in matched pairs. Orthopaedic biomechanics laboratory. Cement was inserted both as a liquid and as a paste in standard and oversized screw holes to augment fixation with plates and screws. Standard 4-point bending tests were performed to obtain stiffness and failure load values. Liquid cement had a 1.38 times increase in stiffness and a failure load 1.84 times greater compared with paste cement, regardless of hole size with a gap at the fracture site (P < 0.05). Liquid cement had a force to failure of 1.77 and 1.91 times in the standard-sized and oversized holes, respectively, when compared with paste cement (P < 0.05). When the cement was inserted in a liquid state in a plated femoral diaphyseal fracture with a gap, screw purchase augmentation achieved greater bending stiffness and resisted a greater failure load.