Effect of a Locking Triple Pelvic Osteotomy Plate on Screw Loosening in 26 Dogs.

OBJECTIVE:
To evaluate the complication rate of the double (DPO) and triple pelvic osteotomy (TPO) procedure (unilateral and bilateral) with a locking purpose-specific plate.
STUDY DESIGN:
Retrospective case series
ANIMALS:
Dogs (n = 26; 38 hips)
MATERIALS:
Medical records (January 2007-January 2011) of dogs that had unilateral or bilateral DPO or TPO were evaluated. Signalment, age, body weight, estimated preoperative subluxation and reduction angles, lameness, and complications were evaluated. Follow-up radiographs were evaluated for implant loosening or failure, femoral head coverage (FCH), pelvic dimensions, and radiographic evidence of healing.
RESULTS:
Screw loosening occurred in 1 of 266 (0.4%) screws placed and in 1 of 38 hips (2.6%). The rate of screw loosening was significantly lower than previously reported. Only 1 hip (2.6%) developed a major complication. Minor complications involving implants occurred in 2 hips (5.3%). Three to 5 locking screws were used per plate. There was a significant increase in FCH and Norberg angle (NA) compared with preoperative values. No clinically significant change in pelvic canal dimensions measured at 3 locations was identified.
CONCLUSION:
Locking 7-hole TPO plates with 3-5 locking screws resulted in a lower rate of major and minor implant associated complications than the reported complication rate for conventional 6-hole plates. En bloc pullout of the caudal aspect of the plate is an infrequent but repeatable complication associated with the locking TPO implant.