Evaluation of locking compression plate fixation of the distal phalanx to the hoof wall as a potential therapy for laminitis.
Authors: Lean, Zedler, Van Eps, Engiles, Ford, Stefanovski, Walsh, Pollitt
Journal: Equine veterinary journal
Summary
# Editorial Summary Surgical stabilisation of the distal phalanx represents an intuitively appealing approach to severe acute laminitis, yet this 2023 study reveals critical limitations that clinicians must understand before considering the technique. Using a cadaver model of thermally-induced lamellar failure combined with vertical loading, researchers demonstrated that T-shaped locking compression plate (LCP) fixation to the dorsal hoof wall successfully prevented the characteristic radiographic markers of distal phalanx displacement—including changes in hoof-distal phalanx distance, coronary extensor process distance, and sole depth. However, when the construct was applied in 12 live Standardbred horses (six standing, six under general anaesthesia), clinical outcomes diverged sharply from mechanical success: whilst 10 of 12 horses remained sound at trot by day 8, histological examination revealed extensive dorsal lamellar pathology with keratinocyte apoptosis (caspase-3 positive cell counts approximately 20-fold higher adjacent to the plate compared to control tissue, p<0.001). The authors attribute this iatrogenic damage to disrupted microvascular perfusion and mechanostatic changes resulting from rigid fixation, highlighting that biomechanical restraint of bony displacement does not necessarily preserve lamellar tissue viability. For practitioners, this demonstrates that whilst LCP fixation prevents catastrophic coffin bone rotation, the technique as currently applied may inadvertently trigger regional tissue death—a sobering reminder that laminitis management demands restoration of vascular and functional integrity, not simply geometric stability.
Read the full abstract on PubMed
Practical Takeaways
- •LCP fixation successfully stabilizes the distal phalanx mechanically but causes significant tissue damage through apoptosis in living horses, limiting its current clinical utility
- •While horses remained clinically sound, microscopic lamellar pathology indicates this technique requires substantial refinement before clinical application for laminitis treatment
- •Future development should focus on understanding and preventing microvascular compromise and abnormal mechanostasis caused by rigid fixation to avoid iatrogenic injury
Key Findings
- •LCP fixation prevented significant DP displacement in cadaver limbs subjected to thermal lamellar failure and vertical load (p<0.05)
- •In vivo application was well-tolerated with 10/12 horses sound at trot on day 8, but induced dorsal lamellar pathology
- •Caspase-3 positive cell counts (indicating apoptosis) were approximately 20-fold higher adjacent to the LCP compared to control (p<0.001)
- •Regional lamellar pathology with extensive keratinocyte apoptosis suggests iatrogenic damage likely due to disturbed microvascular perfusion and/or mechanostasis