Clinical and Radiographic Features of Implant Failure after Fracture Fixation in Dogs and Cats: 37 Cases (2013–2018)

Introduction: Orthopaedic implant failure is an important complication in small animal fracture fixation that can negatively impact bone healing. The objective of this study was to determine clinical and radiographic features of implant failure in dogs and cats after fracture fixation. We hypothesized that mechanical failure is a common feature of small animal fracture repair.

Materials and Methods: A total of 198 dogs and 19 cats that underwent fracture fixation between January 2013 and September 2018 were studied retrospectively. Medical and radiographic records were reviewed to identify patients that underwent fracture fixation with subsequent radiographic evidence of implant failure.

Results: Implant failure was found in 39 fractures in 37 animals (32 dogs and 5 cats), representing 23% of treated cases during the study period. Cases of implant failure had increased risk of delayed union, malunion, or nonunion (p < 0.0001). Implant failures included implant loosening (41%) and plate failure (21%). Bone grafting was used in eight fractures (21%). Major complications were found in 25/39 fractures (64%). Of these fractures, 49% underwent surgical revision. Complications were most often identified after treatment of humeral fractures (26%).

Discussion/Conclusion: Mechanical failure of implants increases the risk of abnormal fracture healing and often requires revision surgery. Constructs are often associated with implant failure if plate bending stiffness is insufficient. Implants of appropriate area moment of inertia (AMI) should be selected through preoperative planning. Our results suggest it is common to select undersized implants. Bone grafting should also be used routinely in adult fracture repairs to promote osteogenesis.

Acknowledgment: There was no proprietary interest or funding involved.