EVALUATION OF NEW PLATE DESIGNS FOR SYMPHYSIS PUBIS INTERNAL-FIXATION

The purpose of this study was to evaluate and compare biplanar and oth er newly designed plates used for pubic symphysis internal fixation to other standard plates. Our data demonstrate that neither of the newly designed symphyseal plates, curved (Zimmer four-hole plate with eithe r two or four 4.5-mm cortical screws) nor the biplanar (Zimmer six-hol e plate with four 4.5-mm cortical screws in one plane and two 4.5-mm c ortical screws in another) significantly reduce motion more than the o ther plates tested (Synthes two-hole 4.5-mm dynamic compression plate with two 6.5-mm cancellous screws and six-hole 3.5-mm reconstruction p late with four 3.5-mm cortical screws). All of the plate constructs we re able to restore motion to nearly that of the intact symphysis pubis and sacroiliac joint. In summary, using the anteroposterior compressi on disruption pattern and model, the disrupted symphysis does gap unde r load but has no effect on sacroiliac joint gapping. It does permit i ncrease in relative flexion angles between the wings of the pelvis. Al l of the plate systems tested restore normal gap motion at the symphys is and normal sacroiliac joint flexion.