the instant invention is a novel method for stabilization of the posterior pelvis when treating an unstable pelvic ring fracture . cannulated screws are inserted through the posterior of the ilium through the sacroiliac joint and into the sacrum . the screws are used to affix the iliosacral joint while it heals . the screws are used in conjunction with a bone plate to provide the construct / fixation with added strength and stability compared to iliosacral fixation using screws alone .