A biomechanical comparison of external skeletal fixation and plating for the stabilization of ilial osteotomies in dogs

Publication date 1st February 2008
Authors Noel Fitzpatrick, A. Cross, D. Lewis


This in vitro study compares the biomechanical properties of two methods of ilial fracture repair in dogs. Ten pelves were harvested from skeletally mature mixed breed dogs weighing 20–27 kg and bilateral oblique ilial body os- teotomies were created. One hemipelvis from each dog was stabilized with a 2.7 mm plate and screws and the contralateral hemipelvis was stabilized with a five pin lin- ear external fixator construct. Each hemipelvis was mounted at an angle of 30° to an actuator platform, such that the acetabulum was centrally loaded by a steel sphere attached to the load cell of a servohydraulic ma- terials testing machine. The construct was loaded at a constant rate of 20 mm/min. A load/displacement curve was generated for each hemipelvis by plotting the sus- tained load against the actuator movement. The stiffness, yield load and failure load for each hemipelvis were de- termined from the load/displacement curve. Bending stiffness was defined as the slope of the load/displace- ment curve from 100 N to yield load. The mode of failure was determined by observations made during testing and gross inspection of each specimen. The mean construct stiffness, yield load and failure load were compared be- tween stabilization groups using a Student’s paired t-test with statistical significance set at p