PSI - Issue 68

Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2025) 000–000 Available online at www.sciencedirect.com ScienceDirect

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 68 (2025) 112–118

European Conference on Fracture 2024 The effect of thread length in cancellous bone fixation under shear loading: A biomechanical study P. Langourani-Kosteletou a *, G. Chelidonis b , E. D. Pasiou b , O. Savvidou c , S. K. Kourkoulis b a 1 st Department of Orthopedics, KAT Attica General Hospital, Nikis 2, Athens, 14561, Greece b National Technical University of Athens, School of Applied Mathematical and Physical Sciences, Department of Mechanics, Laboratory of Biomechanics and Biomedical Physics, Iroon Polytechniou 5, Athens, 15773, Greece c 1 st Department of Orthopedics, National and Kapodistrian University of Athens, School of Medicine, ATTIKON University General Hospital, Rimini 1, Athens, 12462, Greece Abstract The thread length of bone screws is a crucial design parameter directly related to the length of the thread engagement in the bone. For porous materials, like cancellous bone, the length of engagement is correlated with the holding power of screws. The objective of this study is to assess the effect of the thread length in fixation under shear loading, a relatively unexplored area of investigation. For this purpose, sawbone blocks were used as a substitute for cancellous bone, fixed with either a single 6.5 solid-core cancellous screw with a thread length of 16 mm or a single screw with a 32 mm thread length (lag by design). The experiments (shear loading of the constructs) were carried out using an MTS Insight frame. The stiffness, proportionality limit, conventional yield load, and yield displacement were determined for each test piece. The results indicated that the constructs fixed with longer threaded screws had statistically significantly greater stiffness, proportionality limit, and yield force compared to the constructs fixed with shorter threaded screws. This study suggests that the length of thread engagement may affect the resistance of fixation to shear loading. © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ECF24 organizers Keywords: Shear loading; Cancellous bone; Thread length; Biomechanics; Partially threaded screws; © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ECF24 organizers

* Corresponding author. Tel.: +30-697-457-7537. E-mail address: langourani.p@gmail.com

2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ECF24 organizers

2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ECF24 organizers 10.1016/j.prostr.2025.06.030