Biomechanical comparison of locking compression plate fixation and a novel pedicle screw external fixation to repair equine mandibular fractures.
Authors: Monck Samantha L, McGilvray Kirk C, Easley Jeremiah T
Journal: Veterinary surgery : VS
Summary
# Editorial Summary: Mandibular Fracture Fixation in Horses Mandibular fractures represent a significant clinical challenge in equine practice, and whilst locking compression plates (LCP) are commonly employed, alternative fixation methods warrant evaluation. Researchers biomechanically tested locking compression plates against a novel pedicle screw external fixation construct (PDW) using 12 fractured cadaveric equine mandibles (six per group), measuring stiffness, load at failure, and yield strength under quasi-static loading to destruction. Locking compression plates demonstrated substantially greater stiffness (4656 N-m/radian versus 2626 N-m/radian) and failure load (558 N-m versus 315 N-m), yet both constructs exhibited similar yield properties, suggesting comparable early-stage resistance to deformation. A critical finding emerged regarding iatrogenic trauma: tooth root involvement occurred in two LCP constructs with bone fracture failure, whilst PDW constructs failed through wire unraveling and screw bending—mechanical modes that spare dental structures. When contextualised against existing literature, PDW offered biomechanical properties equivalent to several alternative techniques including interdental wire splints and external fixators, positioning it as a viable option that reduces complications. For practitioners, this research suggests that whilst LCP constructs provide superior overall rigidity, the pedicle screw external fixation system merits consideration in cases where preserving tooth vitality is paramount or in patients where hardware removal may prove beneficial.
Read the full abstract on PubMed
Practical Takeaways
- •LCP provides superior rigidity and load-bearing capacity for mandibular fracture repair, but carries increased risk of dental root damage—consider PDW if tooth preservation is a priority
- •PDW (pedicle screw external fixation) offers comparable stability to several established techniques with the added benefit of avoiding iatrogenic tooth injury
- •Failure mode differs between techniques: LCP fails via bone fracture while PDW fails via wire unraveling or screw bending—tailor implant selection to your ability to monitor and maintain the construct
Key Findings
- •Locking compression plates (LCP) achieved significantly greater stiffness (4656 N-m/radian) and load at failure (558 N-m) compared to pedicle screw external fixation (PDW; 2626 N-m/radian and 315 N-m respectively)
- •Yield did not differ significantly between LCP and PDW fixation methods (P = 0.145)
- •LCP constructs caused tooth root involvement in 2 of 6 cases and failed via bone fracture, while PDW constructs failed via wire unraveling and screw bending
- •PDW offers biomechanical stability comparable to intraoral splints, external fixators, and dynamic compression plates while reducing risk of tooth root damage