Risk factors for screw migration after triple pelvic osteotomy.
The objective of this retrospective study was to identify risk factors for screw migration after triple pelvic osteotomy (TPO) in clinical patients. The medical records, radiographs made immediately after surgery, and follow-up radiographs documenting a healed osteotomy were reviewed for 52 dogs treated with unilateral TPO and 38 dogs treated with bilateral TPO. Signalment, surgeon expertise, length of surgery, sequence of surgery in dogs treated bilaterally, use of ischial or ilial wires or both, screw depth in the sacrum, and screw migration were documented for each of the 128 pelvic osteotomies. Screws placed in the first and second plate hole, securing the cranial portion of the plate, loosened most frequently. Factors associated with decreased screw migration included use of an ischial hemicerclage wire and increased depth of sacral purchase with the first and second cranial screws.