An in vitro biomechanical comparison of interlocking nail constructs and double plating for fixation of diaphyseal femur fractures in immature horses.
Authors: Radcliffe R M, Lopez M J, Turner T A, Watkins J P, Radcliffe C H, Markel M D
Journal: Veterinary surgery : VS
Summary
# Editorial Summary: Femoral Fracture Fixation in Immature Horses When treating diaphyseal femoral fractures in young horses, surgeons must choose between interlocking intramedullary nailing and plating techniques, yet limited biomechanical data existed to guide these decisions. Radcliffe and colleagues conducted in vitro testing on 34 immature equine femurs (aged 1–15 months, weighing 68–236 kg), comparing three fixation constructs—interlocking nail alone, interlocking nail with cranial dynamic compression plate, and double dynamic compression plates—against intact bone under nondestructive and destructive loading in multiple planes. Double plating demonstrated superior structural stiffness in both lateromedial and caudocranial bending, matching intact bone properties, whilst all fixation methods proved inferior to intact bone under torsional loading. Significantly, double plating and combined interlocking nail/plate constructs exhibited failure loads comparable to intact bone in lateromedial bending, whereas interlocking nail alone performed less favourably. For practitioners managing comminuted or diaphyseal femoral fractures in immature horses, these findings suggest double plating offers the most robust mechanical stability across loading scenarios, particularly relevant given the young horse's need to return to weight-bearing and exercise.
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Practical Takeaways
- •Double plate fixation provides the best biomechanical stability for diaphyseal femoral fractures in young horses compared to intramedullary nail options, particularly for managing comminuted fractures
- •While all fixation methods tested showed inferior torsional stiffness compared to intact bone, double plating offers the most resistance to rotational forces during the healing phase
- •Consider double plating as the preferred surgical approach for immature horses with comminuted femoral fractures requiring maximum strength and stiffness during recovery
Key Findings
- •Double compression plate (2DCP) fixation demonstrated greater structural stiffness in bending compared to interlocking nail (IIN) and IIN with cranial dynamic compression plate (I/DCP) constructs
- •2DCP constructs had greater torsional stiffness than both IIN and I/DCP constructs, though all fixation methods showed lower torsional stiffness than intact bone
- •Only I/DCP and 2DCP fixations achieved bending stiffness similar to intact immature horse femurs in nondestructive testing
- •2DCP constructs were superior to IIN in resistance to lateromedial bending to failure, with no significant differences from intact bone in yield and failure loads