A biomechanical comparison of double-plate and Y-plate fixation for comminuted equine second phalangeal fractures.
OBJECTIVE
To compare the biomechanical properties, in full limb preparations, of intact second phalanx and a simulated comminuted second phalangeal fracture stabilized with either two bone plates or a custom Y-plate.


METHODS
In vitro biomechanical assessment of intact limbs and of paired limbs with a simulated second phalangeal fracture stabilized by one of two fixation methods. Animal Population-Thirteen pairs of equine cadaveric forelimbs.


METHODS
A comminuted second phalangeal fracture was created in six paired cadaveric limbs. For each limb pair, the fracture was stabilized with two plates in one limb, and with a Y-plate in the contralateral limb. These limbs and seven pairs of intact limbs were subjected to axial compression in a single cycle until failure. Mechanical properties were compared with a mixed-model ANOVA and post hoc contrasts. Joint contact pressure, screw insertion torque, and final screw torque remaining after mechanical testing were also evaluated for constructs.


RESULTS
No significant differences in mechanical testing variables were detected between construct types. However, the Y-Plate construct had significantly greater yield load, yield displacement and yield energy, and failure load and stiffness values than those for intact specimens, whereas the double-plate construct only had greater stiffness than intact specimens. There were no significant differences in joint contact pressures for both constructs. The final screw torque for proximal phalangeal screws was significantly greater for the Y-plate constructs than for double-plate constructs.


CONCLUSIONS
The Y-plate was as effective as the double-plate technique for stabilization of simulated comminuted second phalangeal fractures in monotonically tested equine cadaveric forelimbs.


CONCLUSIONS
This investigation supports evaluation of the Y-plate for repair of comminuted second phalangeal fractures in equine patients. Its specific design may facilitate repair of second phalangeal fractures, and may provide increased stability by allowing the proximal fragments of the second phalanx to be fixed with three screws placed through the plate.
Galuppo
L D
LD
J.D. Wheat Veterinary Orthopedic Research Laboratory, School of Veterinary Medicine, University of California, Davis 95616, USA.
Stover
S M
SM
Willits
N H
NH
D000704:Analysis of Variance; D000818:Animals; D001696:Biomechanical Phenomena; D001860:Bone Plates / Q000662:veterinary*; D002102:Cadaver; D005260:Female; D005552:Forelimb / Q000293:injuries / Q000601:surgery; D005592:Fracture Fixation / Q000662:veterinary*; D050723:Fractures, Bone / Q000601:surgery / Q000662:veterinary*; D006736:Horses / Q000293:injuries* / Q000601:surgery*; D008297:Male; D011897:Random Allocation; D014034:Toes / Q000293:injuries / Q000601:surgery