Effect of bending direction on the mechanical behaviour of 3.5 mm String-of-Pearls and Limited Contact Dynamic Compression Plate constructs

J. Benamou; R. M. Demianiuk; S. Rutherford; C. Beckett; M. G. Ness; R. C. Haut; L. M. Déjardin

doi:10.3415/VCOT-15-01-0013

Veterinary and Comparative Orthopaedics and Traumatology, Table of Contents

Vet Comp Orthop Traumatol 2015; 28(06): 433-440
DOI: 10.3415/VCOT-15-01-0013

Original Research

Schattauer GmbH

Effect of bending direction on the mechanical behaviour of 3.5 mm String-of-Pearls and Limited Contact Dynamic Compression Plate constructs

J. Benamou

¹Collaborative Orthopaedic Investigations Laboratory, Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan

,

R. M. Demianiuk

¹Collaborative Orthopaedic Investigations Laboratory, Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan

,

S. Rutherford

²Croft Veterinary Hospital, Cramlington, Northumberland, United Kingdom

,

C. Beckett

³The Orthopaedic Biomechanics Laboratories, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan

,

M. G. Ness

²Croft Veterinary Hospital, Cramlington, Northumberland, United Kingdom

,

R. C. Haut

³The Orthopaedic Biomechanics Laboratories, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan

,

L. M. Déjardin

¹Collaborative Orthopaedic Investigations Laboratory, Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan

› Author Affiliations

Abstract

Summary

Objective: To compare the bending properties of String-of-Pearls^® (SOP) and Limited Contact Dynamic Compression Plate^® (LCDCP) constructs in orthogonal bending directions.

Methods: 3.5 mm SOP and LC-DCP plates were fixed to a bone model simulating a comminuted tibial fracture. Specimens were non-destructively tested in both mediolateral and craniocaudal bending for 10 cycles. Bending stiffness and total angular deformation were compared using parametric analyses (p <0.05).

Results: For both constructs, stiffness was significantly less when bending moments were applied against the thickness of the plates (mediolateral bending) than against the width (craniocaudal bending). When compared to the mediolateral plane, bending constructs in the craniocaudal plane resulted in a 49% (SOP group) and 370% (LC-DCP group) increase in stiffness (p <0.001). Mediolateral bending stiffness was significantly greater in the SOP than the LC-DCP constructs. Conversely, in craniocaudal bending, SOP constructs stiffness was significantly less than that of the LC-DCP constructs. The differences between the two constructs in total angular deformation had an identical pattern of significance.

Clinical significance: This study found that SOP showed less variability between the orthogonal bending directions than LC-DCP in a comminuted fracture model, and also described the bi-planar bending behaviour of both constructs. Although not exhibiting identical bending properties in both planes, SOP constructs had a more homogenous bending behaviour in orthogonal loading directions. The difference between the SOP with a circular cross sectional shape compared to the rectangular shape of standard plates is probably responsible for this difference.

Keywords

String-of-Pearls - SOP - Limited Contact- Dynamic Compression Plate - LC-DCP - craniocaudal bending - mediolateral bending - stiffness

Full Text

References

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