Vet Comp Orthop Traumatol 2022; 35(04): 246-254
DOI: 10.1055/s-0042-1748859
Original Research

Influence of the Near-Cortical Over-Drilling Technique on the Mechanical Behaviour of Locking Plate Constructs Applied in Maned Wolf's Femur

1   Department of Veterinary Surgery and Anesthesiology, School of Veterinary Medicine and Animal Science, São Paulo State University (UNESP), Rubião Júnior s/n, Botucatu, SP, Brazil
,
Sheila C. Rahal
1   Department of Veterinary Surgery and Anesthesiology, School of Veterinary Medicine and Animal Science, São Paulo State University (UNESP), Rubião Júnior s/n, Botucatu, SP, Brazil
,
Luciana R. Mesquita
1   Department of Veterinary Surgery and Anesthesiology, School of Veterinary Medicine and Animal Science, São Paulo State University (UNESP), Rubião Júnior s/n, Botucatu, SP, Brazil
,
Fabiana A. Voorwald
2   Department of Veterinary Surgery, Federal University of Viçosa, MG, Brazil
,
Martin F. Fernandes
3   Department of Materials and Technology, São Paulo State University (UNESP), Guaratinguetá, São Paulo, Brazil
,
Marcos Tosati
4   Solution Engineering Manager at SAMT - Structural Solutions for Finite Elements, Bauru, Brazil
,
Celso R. Ribeiro
5   Mechanical and Metallography Testing Laboratory – LEMM, Jaú, São Paulo, Rua Luiz Pengo 150, Brazil
,
6   Department of Veterinary Surgery and Anesthesiology, School of Veterinary Medicine and Animal Science, University of Marília (UNIMAR), Marília, São Paulo, Brazil
› Author Affiliations

Abstract

Objective The aim of this study was to evaluate the influence of near-cortical over-drilling holes on the mechanical behaviour of locking plate constructs applied in maned wolf's femur by using mechanical testing and finite element method (FEM).

Study Design Seven pairs of adult maned wolves (Chrysocyon brachyurus) femur bones were randomly distributed into four groups. In all groups, a 3.5 mm locking compression plate, designed with 12 combi-holes and one locked, was applied to the lateral surface of the femur. G1 (n = 4) received bicortical locking screws placed in holes 1, 3, 5, 8, 10 and 12. In G2 (n = 5), the plate was applied as used in G1, but the application of the locked screws involved the near-cortical over-drilling technique. In G3 (n = 4), the plate was applied as used in G2, but the size of the near-cortical over-drilling was larger. The combi-holes 6 and 7 were maintained over a 10 mm fracture gap without screws. All constructs were tested for failure in the axial load. The axial load was applied eccentrically to the femoral head.

Results Statistical differences were observed in the maximum load with G3 > G1 and G3 > G2, and in the deflection with G2 > G1 and G2 > G3. The FEM showed the lowest total displacement of the bone-plate constructs as well as of the plate in G1 compared with G2 and G3.

Conclusion The near-cortical over-drilling technique used in unstable fractures induced in the maned wolf's femur showed by static axial compression test that maximum load and deflection are dependent on drill hole size induced in the near-cortex. Based on FEM, the lowest total displacement of the bone-plate constructs was observed in Group 1.

Authors' Contributions

R.C.S. and S.C.R. contributed to conception of study, study design and acquisition of data and data analysis and interpretation. L.R.M., F.A.V. and P.S.S. contributed to acquisition of data and data analysis and interpretation. M.T. and M.F.F. contributed by performing the finite element analysis. C.R.R. contributed by performing the biomechanical tests. All authors drafted, revised and approved the submitted manuscript.




Publication History

Received: 17 August 2021

Accepted: 04 April 2022

Article published online:
24 May 2022

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