Vet Comp Orthop Traumatol 2022; 35(03): 166-174
DOI: 10.1055/s-0042-1744175
Original Research

Biomechanical Comparison of Use of Two Screws versus Three Screws Per Fragment with Locking Plate Constructs under Cyclic Loading in Compression in a Fracture Gap Model

1   Université de Toulouse, ENVT, Toulouse, France
,
1   Université de Toulouse, ENVT, Toulouse, France
,
Pascal Swider
2   Université de Toulouse, IMFT UMR 5502, Toulouse, France
,
1   Université de Toulouse, ENVT, Toulouse, France
› Author Affiliations
Funding None.

Abstract

Objectives The aim of this study was to measure and compare the stiffness and cyclic fatigue of two plate-bone model constructs, with either two or three locking screws per fragment, under cyclic compression.

Methods A 10-hole 3.5 mm stainless steel locking compression plate (LCP) was fixed 1 mm from a synthetic bone model in which the fracture gap was 47 mm. Two groups of 10 constructs, prepared with either two or three bicortical locking screws placed at the extremities of each fragment, were tested in a load-controlled compression test until failure.

Results The three-screw constructs were stiffer than the two-screw constructs (196.75 ± 50.48 N/mm and 102.43 ± 22.93 N/mm, respectively) and the actuator displacements of the two-screw constructs were higher (18.02 ± 1.07 mm) than those of the three-screw constructs (14.48 ± 2.25 mm). The number of cycles to failure of the two-screw constructs was significantly lower (38,337.50 ± 2,196.98) than the that of the three-screw constructs (44,224.00 ± 1,515.24). Load at irreversible deformation was significantly lower in the two-screw constructs (140.93 ± 13.39 N) than in the three-screw constructs (184.27 ± 13.17 N). All constructs failed by plate bending at the gap between the two cylinders.

Clinical Significance Omission of the third innermost locking screw during bridging osteosynthesis subjected to compression forces led to a 13.3% reduction in the number of cycles to failure and a 23.5% reduction of the load withstood by the plate before plastic deformation occurred.

Author's Contribution

S.P. and A.A. were the primary investigators, adapted the study concept and design, performed data collection, data analysis and statistical analysis and wrote the manuscript. P.S. helped for setup of the study concept and design and critical review of the manuscript. M.B. helped with data collection as well as data analysis and and critical review of the manuscript. All authors agree to be publicly accountable for the content of the manuscript.




Publication History

Received: 18 May 2021

Accepted: 27 January 2022

Article published online:
10 March 2022

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