The strength of iliosacral lag screws and transiliac bars in the fixation of vertically unstable pelvic injuries with sacral fractures.

This study compares the relative strengths of iliosacral lag screws and transiliac bars in the fixation of vertically unstable pelvic injuries with sacral fractures. A vertical sacral fracture was artificially induced by vertical loading in eight pelvises from cadavers, which were then fixed with two 6.5 mm iliosacral lag screws or two 6.4 mm transiliac bars. The pelvises were then loaded again to failure. The mean strength of iliosacral lag screw fixation was 819 newtons and for transiliac bars it was 1066 newtons, but the study was too small for the difference to be judged as statistically significant. Various advantages and disadvantages of each method of fixation are discussed.