Clinical and Translational Research
Copyright ©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Jul 16, 2023; 11(20): 4814-4823
Published online Jul 16, 2023. doi: 10.12998/wjcc.v11.i20.4814
Mechanical analysis of the femoral neck dynamic intersection system with different nail angles and clinical applications
Ying Wang, Jian-Xiong Ma, Hao-Hao Bai, Bin Lu, Lei Sun, Hong-Zhen Jin, Xin-Long Ma
Ying Wang, Jian-Xiong Ma, Hao-Hao Bai, Bin Lu, Lei Sun, Hong-Zhen Jin, Xin-Long Ma, Orthopaedics Institute, Tianjin Hospital, Tianjin University, Tianjin 300050, China
Author contributions: Wang Y, Ma JX and Bai HH contributed equally to this work; Wang Y, Ma JX, and Ma XL conceived the theme of study and drafted the manuscript; Wang Y and Bai HH recruited volunteers and collected CT data; Lu B and Sun L conducted three-dimensional model modeling and preprocessing; Jin HZ and Wang Y conducted finite element modeling and analysis; All authors have read and approved the final manuscript.
Supported by Tianjin Science and Technology planning Project, No. 21JCQNJC01060; Key Project of Tianjin Natural Science Foundation, No. 22JCZDJC00340; and National Key Research and Development Project of China, No. 2022YFC3601904.
Institutional review board statement: The study was reviewed and approved by the Tianjin Hospital ethics committee [Approval NO.2023.023].
Conflict-of-interest statement: All authors declare that they have no conflict of interest.
Data sharing statement: The datasets are available from the corresponding author at maxinlong@126.com.
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: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Xin-Long Ma, MD, Professor, Orthopaedics Institute, Tianjin Hospital, Tianjin University, Heping District Munan Road No. 155 Tianjin 300050, China. maxinlong@126.com
Received: May 11, 2023
Peer-review started: May 11, 2023
First decision: May 31, 2023
Revised: June 7, 2023
Accepted: June 25, 2023
Article in press: June 25, 2023
Published online: July 16, 2023
Abstract
BACKGROUND

The femoral neck dynamic intersection system (FNS) is mechanically more stable than other internal fixation techniques. Current studies have confirmed that the structural design of FNS has good biomechanical properties in European and American populations. However, whether the suitability of the FNS's 130° main nail angle design for Asian populations has been thoroughly investigated remains unclear.

AIM

To compare the biomechanical stability differences among different main nail angles of the FNS in the treatment of femoral neck fractures in Asian populations.

METHODS

Computed tomography data of the femur of healthy adult male volunteers were imported into Mimics software to create a three-dimensional model of the femur. The model was adapted to the curve using Geomagic software and imported into Solidworks software to construct the Pauwels I femoral neck fracture model and design the FNS internal fixation model using different main nail angles. Afterward, the models were assembled with the FNS fracture model and meshed using the preprocessing Hypermesh software. Subsequently, they were imported into Abaqus software to analyze and evaluate the biomechanical effects of different angles of the FNS main nail on the treatment of femoral neck fractures.

RESULTS

The peak displacement of the proximal femur under different angles of FNS fixation under stress was 7.446 millimeters in the 120° group and 7.416 millimeters in the 125° group; in the 130°, 135°, and 140° FNS fixation groups, the peak displacement was 7.324 millimeters, 8.138 millimeters, and 8.246 millimeters, respectively. In the 120° and 125° FNS fixation groups, the maximum stresses were concentrated at the main nail and the anti-rotation screw, which intersected the fracture line of the femur neck, resulting in peak stresses of 200.7 MPa and 138.8 MPa, respectively. Peak stresses of 208.8 MPa, 219.8 MPa, and 239.3 MPa were observed on the angular locking plate distal to the locking screw in the 130°, 135°, and 140° fixation groups.

CONCLUSION

FNS has significant stress distribution properties, a minimal proximal femoral displacement, and an optimal stability for treating femoral neck fractures in Asian populations when performed with a 130° main nail angle.

Keywords: Femoral neck dynamic intersection system, Biomechanics, Three-dimensional reconstruction, Nail angle, Finite element analysis, Stress

Core Tip: Current studies have confirmed that the structural design of the femoral neck dynamic intersection system (FNS) has good biomechanical properties in European and American populations. However, no relevant research report currently addresses the suitability of the 130° staple design of FNS for Asian populations. Herein, we compared the biomechanical stability differences in various FNS main nail angles for treating femoral neck fractures in Asian populations. We found that, in Asian populations, a main nail FNS angle of 130° has the best stability for treating femoral neck fractures with quantifiable stress distribution and minimal proximal femoral displacement.