Fracture Repair Using a Polyaxial Locking Plate System (PAX)


Corresponding Author

Matthew Barnhart, DVM, MS, Diplomate ACVS, MedVet Medical and Cancer Centers, 300 E. Wilson Bridge Rd, Worthington, OH 43085




To report outcomes and complications of dog and cat fractures treated with the polyaxial locking plate system (PAX).

Study Design

Case series.


Dogs (n = 60) and 2 cats.


Medical records (December 2009–March 2011) of dogs and cats with fractures treated with the PAX system were reviewed. Cases with adequate follow-up to document a functional union, had surgery performed by an author, had no prior treatment of the fracture(s), and with complete operative records were included. Signalment, body weight, bone(s) fractured, area of bone fractured, fracture classification, concurrent orthopedic injuries, complications, time to functional union, if minimally invasive plate osteosynthesis (MIPO) techniques were used, plate size, number of plates, bone graft use, and ancillary methods of fixation were recorded. Additionally, fracture segment: plate length, screw, number of plate holes, number of empty screw holes overlying/adjacent to the fractures, number of cortices engaged above/below the fracture was evaluated. Variables were evaluated statistically for effect on complications and functional union.


Sixty-two animals were included. Mean time to functional union was 7.1 weeks. Complications occurred in 12 animals (19%) and plate failure occurred in 3 (5%). Statistically significant factors that affected time to functional union were the presence of multiple injuries and age. Those associated with complications were double plates and number of cortices engaged above and below fractures.


The PAX system allows for multidirectional screw insertion with an overall complication rate and time to functional union similar to other fracture repair implant systems.