Evaluation of different shape-memory staple configurations against crossed screws for first metatarsophalangeal joint arthrodesis: A biomechanical study
File(s)MTPJ arthrodesis paper for Symplectic.pdf (597.17 KB)
Accepted version
Author(s)
Willmott, H
Al-Wattar, Z
Halewood, C
Dunning, M
Amis, A
Type
Journal Article
Abstract
BACKGROUND: The first metatarsophalangeal joint may be fused in order to treat arthritis or instability. The use of shape-memory staples for fixation is well recognised, but little work has been done into the optimal configuration of staples. METHODS: The structural behaviour of first metatarsophalangeal joint (MTPJ) arthrodeses using shape-memory staples or crossed screws was studied using cadaveric porcine joints. Five fixation configurations were tested: single vertical or horizontal staple, paired staples in dorsal-medial configuration (0-90° to the sagittal plane), paired staples in oblique orthogonal configuration (45-135°); or two crossed screws. Specimens were loaded in cyclical dorsiflexion for 1000 cycles. Plantar gapping and shearing were measured. Specimens were then loaded to failure. RESULTS: Cyclic testing caused more shear in the 45-135° staples than the crossed screws (1.0mm±0.5mm compared to 0.14mm±0.4mm, p<0.01). No significant difference was found in plantar gap formation. Single vertical and horizontal single staples failed at 15N and 19. CONCLUSIONS: N, respectively. Paired 0-90° staples failed at 43N±9N, significantly lower than the 45-135° staples (141N±25N; p<0.001) and crossed screws (180N±67N; p<0.001). There was no significant difference between the 45-135° staples and crossed screws. Screws failed by sudden cortical fracture; staples displayed gradual pull-out and shearing. First MTPJ arthrodeses fixed with single staples are not recommended. Arthrodeses fixed with staples at 0-90° to the sagittal plane were significantly less strong than two crossed screws. However, positioning oblique staples at 45-135° significantly improved stability, creating a construct as strong as, crossed screws. None of the constructs was strong enough for immediate weight bearing.
Date Issued
2018-06-01
Date Acceptance
2017-03-02
Citation
Foot and Ankle Surgery, 2018, 24 (3), pp.259-263
ISSN
1268-7731
Publisher
Elsevier
Start Page
259
End Page
263
Journal / Book Title
Foot and Ankle Surgery
Volume
24
Issue
3
Copyright Statement
© 2017 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/29409249
PII: S1268-7731(17)30052-8
Subjects
Arthrodesis
Biomechanics
Metatarsophalangeal joint
Screws
Staples
Publication Status
Published
Coverage Spatial
France
Date Publish Online
2017-03-18