Biomechanical Comparison of ALPS, FIXIN, LCP And DCP Plates in a Feline Ilial Fracture Model

Introduction: Ilial fractures are a common encountered problem in cats after trauma. Complications after fixation are frequent. Biomechanical evaluation of different plate systems, including locking versus non-locking constructs are limited in the current literature. Therefore, our purpose was to biomechanically compare different locking-plate systems to a standard DCP for feline ilial fractures.

Materials and Methods: Fresh-frozen feline hemipelves (n = 24) were randomly assigned to one of the four lateral plating groups: (1) Advanced Locking Plate System (ALPS) (2), Locking Compression Plate (LCP), (3) FIXIN Plate (FIXIN) and (4) a standard Dynamic Compression Plate. A standardized long oblique osteotomy was performed before applying the plates according to group. Each specimen was subjected to sinusoidal cyclic axial loading until the test stop criterion of 10 mm axial displacement was reached. Statistical analysis was performed with parametric tests.

Results: Significant differences were detected for the LCP and FIXIN groups, withstanding significantly more cycles to 1 mm, 2 mm and 5 mm displacement compared with the DCP. No significant differences were found between the ALPS and DCP groups. No significant differences were found for construct stiffness. In the DCP group, screw loosening was the predominant mode of failure, which was not found in the locking plate groups.

Discussion/Conclusion: A significantly increased fatigue life was found for LCP and FIXIN when compared with DCP. Screw loosening as mode of failure was exclusively found in the DCP group resembling the findings in clinical patients and emphasizing the role of locking implants in feline ilial fractures.

Acknowledgement: Fixin Intrauma and Kyon donated the implants for this study.