Comparison of Bending Stiffness between String of Pearls Plate-Bone Substitute Constructs with and without Bending Tees in a Fracture Gap Model

Abstract

Objective The aim of this study was to compare the bending properties of String of Pearls plate-bone substitute constructs with and without bending tees in the nodes over a simulated fracture gap. It is hypothesized that the constructs with tees will have higher bending stiffness.

Study Design Acetal polymer tubes and 12-hole, 3.5-mm String of Pearls plates were used to create plate-bone substitute constructs simulating stabilization in a bridging fashion over a 45-mm gap. Twenty-four constructs were made with 12 containing tees in the nodes over the fracture gap. Single-cycle load-to-failure 4-point bending was performed in mediolateral and craniocaudal planes. Bending stiffness was compared with a t-test (p < 0.05).

Results All plate-bone substitute constructs had a permanent loss of structural integrity via plastic deformation of the plate. The bending stiffness (mean ± standard deviation) of the craniocaudal group was 59.11 ± 1.98 N/mm with tees and 59.25 ± 1.69 N/mm without tees (p = 0.88). In the mediolateral group, the bending stiffness was 43.17 ± 0.75 N/mm with tees and 41.09 ± 0.91 N/mm without tees (p = 0.0042).

Conclusion In 4-point bending, the plate-bone substitute constructs with tees had equivalent bending stiffness in the craniocaudal plane and increased bending stiffness in the mediolateral plane. However, with a small absolute difference in values, the clinical significance is unclear. Future studies for cyclic bending, torsional, and axial compression tests should be performed to further investigate the value of tees in the nodes over a comminuted or gap fracture repaired in a bridging fashion.

Keywords

bending tees - mechanical testing - 4-point bending - String of Pearls - fracture gap model

Note

Content from this study was presented as an abstract at the Veterinary Orthopedic Society Annual Conference; March 11–18, 2023; Big Sky, Montana.

Authors' Contribution

P.-H.L. and K.M.C. contributed to the conception, study design, acquisition of data, data analysis and interpretation. R.F. contributed to acquisition of data, data analysis and interpretation. E.H. contributed to the study design, data analysis and interpretation. K.K. contributed to study design. B.M. contributed to the conception and study design. All authors drafted, revised, and approved the submitted manuscript and are publicly responsible for the relevant content.

Publication History

Received: 30 September 2023

Accepted: 09 August 2024

Article published online:
20 September 2024

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