Observational Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Aug 6, 2021; 9(22): 6343-6356
Published online Aug 6, 2021. doi: 10.12998/wjcc.v9.i22.6343
Selection of internal fixation method for femoral intertrochanteric fractures using a finite element method
Jia-Xuan Mu, Shi-Yang Xiang, Qing-Yu Ma, Hai-Lun Gu
Jia-Xuan Mu, Shi-Yang Xiang, Qing-Yu Ma, Hai-Lun Gu, Department of Orthopedics, Shengjing Hospital, China Medical University, Shenyang 117004, Liaoning Province, China
Author contributions: Mu JX conceived and coordinated the study, designed, performed, and analyzed the experiments, and wrote the paper; Xiang SY, Ma QY, and Gu HL carried out data collection and analysis and revised the paper; all authors reviewed the results and approved the final version of the manuscript.
Institutional review board statement: The study was reviewed and approved by the ethic committee of Shengjing Hospital, China Medical University.
Informed consent statement: All study participants, or their legal guardian, provided informed written consent prior to study enrollment.
Conflict-of-interest statement: There are no conflicts of interest to report.
Data sharing statement: No additional data are available.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Hai-Lun Gu, PhD, Doctor, Department of Orthopedics, Shengjing Hospital, China Medical University, No. 36 Sanhao Street, Heping District, Shenyang 117004, Liaoning Province, China. guhailun_@163.com
Received: April 7, 2021
Peer-review started: April 7, 2021
First decision: April 23, 2021
Revised: May 23, 2021
Accepted: June 3, 2021
Article in press: June 3, 2021
Published online: August 6, 2021
Processing time: 111 Days and 23 Hours
Abstract
BACKGROUND

Failure to fix unstable intertrochanteric fractures impairs return to daily activities.

AIM

To simulate five different internal fixation methods for unstable proximal femoral fractures.

METHODS

A three-dimensional model of the femur was established from sectional computed tomography images, and an internal fixation model was established. Finite element analysis of the femur model was established, and three intertrochanteric fracture models, medial defect, lateral defect, and medial-lateral defects, were simulated. Displacement and stress distribution after fixation with a proximal femoral anti-rotation intramedullary nail (PFNA), integrated dual-screw fixation (ITN), PFNA + wire, PFNA + plate, and PFNA + wire + plate were compared during daily activities.

RESULTS

The maximum displacement and stress of PFNA and ITN were 3.51 mm/473 MPa and 2.80 mm/588 MPa for medial defects; 2.55 mm/288 MPa and 2.10 mm/307 MPa for lateral defects; and 3.84 mm/653 MPa and 3.44 mm/641 MPa for medial-lateral defects, respectively. For medial-lateral defects, reconstructing the medial side alone changed the maximum displacement and stress to 2.79 mm/515 MPa; reconstructing the lateral side changed them to 3.72 mm/608 MPa, when both sides were reconstructed, they changed to 2.42 mm/309 MPa.

CONCLUSION

For medial defects, intramedullary fixation would allow early low-intensity rehabilitation exercise, and ITN rather than PFNA reduces the risk of varus and cut-out; for lateral wall defects or weakness, intramedullary fixation allows higher-intensity rehabilitation exercise, and ITN reduces the risk of varus. For both medial and lateral defects, intramedullary fixation alone will not allow early functional exercise, but locating lateral or medial reconstruction will. For defects in both the inner and outer sides, if reconstruction cannot be completed, ITN is more stable.

Keywords: Hip fractures; Fracture fixation, Intramedullary; Finite element analysis

Core Tip: This study modeled different internal fixation methods for unstable proximal femoral fractures. Finite element analysis of the femur model was established and three intertrochanteric fracture models were simulated. For medial defects, intramedullary fixation would allow early low-intensity rehabilitation exercise, and integrated dual-screw fixation (ITN) rather than proximal femoral anti-rotation intramedullary nail reduces the risk of varus and cut-out; for lateral wall defects or weakness, intramedullary fixation allows higher-intensity rehabilitation exercise, and ITN reduces the risk of varus. For both medial and lateral defects, intramedullary fixation alone will not allow early functional exercise but locating lateral or medial reconstruction will.