An in vitro biomechanical investigation of an interlocking nail for fixation of diaphyseal tibial fractures in adult horses.

The research focuses on the mechanical properties of a certain type of nail used for fixation of tibial fractures in adult horses. It compares how well these nails, when combined with bone segments, handle different forces compared to intact bones. Through this investigation, researchers found that modifications are needed for the nail-design to enhance its effectiveness in treating equine tibial fractures.

Objective and Methodology

• The goal of the study was to determine the clinical suitability of an interlocking intramedullary nail in repairing tibial fractures in adult horses.
• The researchers compared the mechanical properties of adult equine tibiae (lower leg bones), specifically their ability to sustain compressive, bending, and torsional forces, when fixed with these nails versus intact tibiae.
• The focus was on yield load (the amount of load that can be sustained before permanent deformation), failure load (the load capacity before breakage), and stiffness.

Findings

• When compared with intact tibiae, nail-tibia composites performed significantly worse across all load configurations.
• The nail-tibia composites could handle more compressive yield load than what was previously reported as the in vivo load for walking and trotting.
• However, the nail-tibia composites didn’t fare as well with torsional loads. Their yield loads were less than the one from another in vivo study that measured the load during a walk.

Recommendations

• Based on the study findings, modifications are needed in the design of interlocking nails to successfully treat adult equine tibial fractures.
• These modifications include enhancements to increase the torsional and compressive yield strengths, as well as torsional stiffness.
• The researchers recommend these improvements before any level of success could be anticipated for the nail’s use in equine fracture treatment.