Sacroiliac screw fixation for tile B fractures.

Abstract

The purpose of this comparative cadaveric study was to investigate whether the stability of partially unstable pelvic fractures can be improved by combining plate fixation of the symphysis with a posterior sacroiliac screw. In six specimens, a Tile B1 (open-book) pelvic fracture was created. We compared the intact situation with isolated anterior plate fixation and plate with sacroiliac screw fixation. Using a three-dimensional video system, we measured the translation and rotation stiffness of the fixations and the load to failure. Neither absolute displacements at the os pubis or at the sacroiliac joint nor stiffness of the ilium with respect to the sacrum were significantly different for the techniques with or without sacroiliac screw or the intact situation. Load to failure was reached in only one of the six cases. In all other cases, the fixation of the pelvis to the frame failed before failure of the fixation itself. In these cases, a load of approximately 1,000 N or more could be applied. The addition of a sacroiliac screw in a Tile B1 fracture does not provide significant additional stability. Although cyclic loading was not tested, in these experiments forces could be applied that were similar to full body weight. Clinical experiments into direct postoperative weight bearing are recommended to examine the clinical situation.