THE EFFECTS OF PLATE-TYPE, ANGLE OF ILIAL OSTEOTOMY, AND DEGREE OF AXIAL ROTATION ON THE STRUCTURAL ANATOMY OF THE PELVIS

Unilateral triple pelvic osteotomy was performed with three variations in technique on canine cadaver pelves. The following variables were s tudied: the angle of the ilial osteotomy (perpendicular to the long ax is of the ilium and 10 degrees, 20 degrees, and 30 degrees off perpend icular); the degree of axial rotation (20 degrees, 30 degrees, and 45 degrees); and the type of fixation (canine pelvic osteotomy plate [CPO P] or a 2.7-mm dynamic compression plate [DCP]). Structural changes me asured were the pelvic inlet and acetabular area, interischiatic tuber osity distance, and degree of acetabular version. Means and standard e rror of the means were determined for all pelvic measurements and were analyzed by three-way analysis of variance (P <.05). As the axial rot ation increased from 20 degrees to 45 degrees an ilial osteotomy angle d 10 degrees, 20 degrees, or 30 degrees resulted in a significantly gr eater decrease in the pelvic inlet area and significantly less deviati on of the interischiatic tuberosity distance and degree of acetabular version from normal than an osteotomy directed perpendicular to the lo ng axis of the ilium. Compared with the CPOP, as the axial rotation in creased from 20 degrees to 45 degrees, the DCP resulted in a significa ntly greater decrease in the pelvic inlet area, an increase in the int erischiatic tuberosity distance and degree of acetabular version, and less of an increase in the acetabular area. The results of this study suggest that to maximize dorsal acetabular coverage, while minimizing disruption of normal pelvic architecture, a CPOP and an ilial osteotom y angled 10 degrees to 30 degrees are preferred for all degrees of axi al rotation. (C) Copyright 1994 by The American College of Veterinary Surgeons