Objective: To compare the feasibility and biomechanical stability of two surgical techniques for fixation of vertical plane fractures of the accessory carpal bone (ACB).
Study design: Randomized experimental ex vivo study.
Sample population: Eight equine accessory carpal bones were included in a control group. A total of 20 equine cadaveric forelimbs were randomly assigned into two groups (n = 10 per group).
Methods: Vertical plane fractures were created palmar to the extensor sulcus using an oscillating saw. In Group 1 (CS), fractures were stabilized with two 4.5 mm cortical screws in lag fashion. In Group 2 (XP), fixation included one 4.5 mm cortical screw in lag fashion and a laterally applied angular stable X-plate with four 2.7 mm locking screws. Control ACBs were excised and tested under axial compression using a four-column testing machine. Postoperative specimens in Groups CS and XP were tested under the same conditions. The failure mode was assessed radiographically.
Results: The mean maximum strength of native bone was 11.26 (±2.14) kN. Two constructs per group were excluded due to cortical screw protrusion. No difference in failure load was observed (CS: 6.82 [±2.34] kN; XP: 8.02 [±1.10] kN; p = .7558). Failure mode analysis revealed a greater fracture gap size (p = .0039) and implant bending in CS specimens (p = 1.074e-7).
Conclusion: Both techniques were feasible, though neither restored native bone strength.
Clinical significance: A lateral X-plate with a single cortical screw demonstrated equivalent biomechanical performance to two cortical screws and was technically less demanding, offering a simpler fixation option for ACB fractures.
© 2025 The Author(s). Veterinary Surgery published by Wiley Periodicals LLC on behalf of American College of Veterinary Surgeons.