Equine ulnar fracture repair with locking compression plates can be associated with inadvertent penetration of the lateral cortex of the radius.
Authors: Kuemmerle Jan M, Kühn Karolin, Bryner Marco, Fürst Anton E
Journal: Veterinary surgery : VS
Summary
# Editorial Summary When surgeons repair equine ulnar fractures using locking compression plates applied to the caudal ulna, the standard perpendicular insertion of locking head screws (LHS) in the distal plate holes risks penetrating the lateral cortex of the radius—a complication that doesn't occur with angled cortex screws (CS). In this controlled cadaveric study, researchers compared two fixation approaches across eight paired equine forelimbs: distal holes secured with either standard 4.5 mm cortex screws inserted at an average angle of 17.6° from the sagittal plane in a caudolateral-craniomedial direction (group 1), or perpendicular 5.0 mm locking head screws (group 2). Imaging and dissection revealed that whilst no radial cortex penetration occurred in group 1, four of eight limbs in group 2 demonstrated iatrogenic injury, affecting 6 of 24 locking screws (p<0.05). The findings suggest that surgeons should consider either angling cortex screws away from the radius or repositioning locking plate placement entirely, as the anatomical proximity of the distal ulna to the radius cortex creates an inherent hazard when perpendicular screw insertion is used—a consideration that could prevent complications affecting implant stability and adjacent joint mechanics in clinical cases.
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Practical Takeaways
- •When using locking compression plates for ulnar fractures on the caudal aspect, avoid perpendicular insertion of locking head screws in distal holes due to high risk of penetrating the adjacent radius
- •Cortex screws inserted at an angle (caudolateral-craniomedial direction) provide safer osteosynthesis for distal ulnar plate fixation
- •Consider alternative screw types or plate positioning techniques when treating distal ulnar fractures to minimize iatrogenic injury to the radius
Key Findings
- •Locking head screws (LHS) in distal holes of caudal ulnar plates caused lateral radius cortex penetration in 4/8 limbs (50%), versus 0/8 with cortex screws
- •6 of 24 LHS (25%) resulted in iatrogenic radius cortex injury when inserted perpendicular to the plate
- •Cortex screws inserted at mean angle of 17.6° from sagittal plane (caudolateral-craniomedial) avoided radius injury
- •LHS perpendicular insertion technique is associated with significant risk of inadvertent radius cortex penetration