PELVIC CANAL NARROWING CAUSED BY TRIPLE PELVIC OSTEOTOMY IN THE DOG .1. THE EFFECT OF PUBIC REMNANT LENGTH AND ANGLE OF ACETABULAR ROTATION

During a triple pelvic osteotomy, rotation of the free acetabular segm ent causes the pubic remnant on the acetabulum to rotate into the pelv ic canal. The resulting narrowing may cause complications by impingeme nt on the organs within the pelvic canal. Triple pelvic osteotomies we re performed on ten cadaver pelves with pubic remnants equal to 0, 25, and 50% of the hemi-pubic length and angles of acetabular rotation of 20, 30, and 40 degrees. All combinations of pubic remnant lengths and angles of acetabular rotation caused a significant reduction in pelvi c canal-width and cross-sectional area, when compared to the inact pel vis. Zero, 25, and 50% pubic remnants result in 15, 35, and 50% reduct ions in pelvic canal width respectively. Overrotation of the acetabulu m should be avoided and the pubic remnant on the acetabular segment sh ould be minimized to reduce postoperative complications due to pelvic canal narrowing.