Complex Extra-articular Proximal Third Canine Tibial Fractures: In Vitro Biomechanical Evaluation of Four Methods of Fixation

Objectives
To compare (1) the biomechanical performance of a 3.5 mm locking compression plate (LCP) applied to an experimentally induced canine proximal tibial gap fracture with a 3.5 mm broad low-contact dynamic compression plate-rod (DCP-R) and a 6 mm standard interlocking nail (ILN) construct, and to evaluate (2) the biomechanical performance of a novel 3.5 mm proximal medial tibia locking plate (PMTLP) in comparison with a DCP-R construct.

Study design
Biomechanical cadaveric study.
Sample population: Cadaveric canine tibiae (n = 21 pairs) from skeletally mature dogs with a 10 mm gap ostectomy in the proximal third of tibiae mimicking a 41 A-3 fracture.

Methods
Tibiae were stabilised with one of 4 implants: LCP, DCP-R, ILN and PMTLP. For (1), LCP constructs acted as reference implants and were randomly assigned against matching tibiae with either DCP-R (n = 7) or ILN (n = 7). For (2), tibiae with PMTLP (n = 7) were matched with DCP-R (n = 7) constructs. Axial gap stiffness of all constructs was determined by non-destructive eccentric compression tests. LCP, ILN and DCP-R constructs were additionally tested in torsion. Axial gap stiffness and structural torsion stiffness were compared with paired T tests between paired constructs and independent sample T tests between unpaired constructs. The significance level for all statistical analyses was set as a value of p < 0.05.  [...]