| Abstract: | Objective: To compare the mechanical properties and failure modes of a standardized short oblique distal radial metaphyseal osteotomy stabilized using either a transfixation pin cast (TPC), a modular‐sidebar external skeletal fixator (ESF), or a solid‐sidebar ESF (modular‐ or solid‐ESF, respectively) using static or cyclic axial loading to failure. Study Design: In vitro study. Animals: Equine cadaver forelimbs. Methods: A 30° oblique distal radial osteotomy was created and stabilized using 1 of the 3 fixation methods: (1) TPC, (2) modular‐ESF, or (3) solid‐ESF. Limbs were tested using static (TPC, modular‐ESF, and solid‐ESF) or cyclic (TPC and solid‐ESF) axial loading to failure. The stiffness, yield load, yield displacement, failure load, and failure displacement for static loading and the cycles to failure for cyclic loading at 75% failure load were obtained. Data were analyzed using a Kruskal–Wallis test. Level of significance was P<.05. Results: The solid‐ESF had a greater stiffness, higher yield and failure load and a lower yield and failure displacement than the TPC (P=.01) and the modular‐ESF (P=.02). TPC had a higher yield load, failure load, and yield displacement than the modular‐ESF (P=.01). Mean cycles to failure for TPC was 2996±657 at a load of 16,000 N and for solid‐ESF 6560±90 cycles at a load of 25,000 N. Conclusions: The solid‐ESF was stiffer and stronger than the TPC and modular‐ESF and failed at a greater number of cycles in axial loading compared with the TPC. Clinical Relevance: This study is an initial step in evaluating the solid‐ESF. Further testing needs to be performed, but this fixation may offer a viable alternative to the traditional TPC for stabilization of long bone fractures in adult horses. |
