Plate failure by bending following tibial fracture stabilisation in ten cats

Objective: Describe the clinical findings and management of tibial fractures in cats in which plate osteosynthesis failed due to plate bending.Study Design: Multicentre, retrospective clinical study.Methods: Clinical histories and radiographs of 10 cats that suffered plate bending following plate or plate-rod fixation of tibial fractures were reviewed for signalment, fracture configuration and repair, post-operative and post-failure tibial alignment, ultimate treatment and outcome. Tibial alignment post-operatively and post-failure was compared using a paired T-test.Results: Mean age was 5.3 years and mean body weight was 5.0kg. All ten cats sustained complete fracture of the tibia with an accompanying fracture to the fibula. Tibial fractures were generally oblique (4/10) or spiral (4/10) with mild comminution (8/10) and located in the middle (3/10) or distal (6/10) third of the tibia. Initial fracture stabilisation was with aplate (6/10) or plate-rod combination (4/10) with the plate applied to the medial tibial surface. Non-reduced, lateral tibial wedge fragments were present in 5 fractures. Mean time to implant failure was 24 days. Mean tibial valgus angle increased from 12.9° to 30.9° following bending of the plate (p=<0.01). Revision surgery was performed in 6/10 cats using orthogonal plating (4/10); stacked medial plates (1/10) or a combination of a stacked medial plate with an orthogonal cranial plate (1/10). Short-term outcome following revision surgery was favourable with improvement in tibial valgus in all 5 fractures with follow-up data (p-<0.05).Conclusions: Bending of plates applied to stabilise tibial fractures in these 10 cats caused tibial valgus deformation. Implant failure was commonly associated with a reduced ciscortex, but a non-reduced lateral tibial wedge fragment. Attention to plate and/or pinselection and application should be made to avoid stress overload of the plate. Revision using orthogonal plating or stacked medial plates was uniformly successful