Associations of age and nail-tract bone density with postoperative stability in proximal femoral nail anti-rotation-Ⅱ fixation for geriatric intertrochanteric fractures: a finite-element analysis
10.3760/cma.j.cn115530-20250403-00144
- VernacularTitle:亚洲型股骨近端防旋髓内钉固定老年股骨转子间骨折中年龄及钉道骨密度与术后稳定性的有限元分析
- Author:
Yufeng GE
1
;
Chen YI
;
Dongchen YAO
;
Yu LI
;
Rui ZHANG
;
Ling WANG
;
Yong XUN
;
Minghui YANG
;
Shiwen ZHU
;
Xinbao WU
Author Information
1. 首都医科大学附属北京积水潭医院创伤骨科，国家骨科医学中心，北京 100035
- Publication Type:Journal Article
- Keywords:
Hip fractures;
Fracture fixation, intramedullary;
Bone density;
Finite element analysis;
Aged;
Proximal femoral nail anti-rotation-Ⅱ
- From:
Chinese Journal of Orthopaedic Trauma
2025;27(9):806-812
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate how age and nail-tract volumetric bone mineral density (vBMD) are associated with postoperative mechanical performance of proximal femoral nail anti-rotation (PFNA-Ⅱ) fixation for geriatric intertrochanteric fractures using a finite-element analysis.Methods:Fifteen elderly patients with intertrochanteric fracture of the femur were selected for this study. They were 11 females and 4 males and divided into 5 groups based on their ages ( n=3): 55-year-old, 65-year-old, 75-year-old, 85-year-old, and 95-year-old groups. After three-dimensional models of the proximal femur were constructed using the preoperative CT data of their healthy contralateral hip, 31-A1.2 fractures of the AO/OTA type were created and PFNA-Ⅱ fixations simulated. Two loading schemes were created: graded quasi-static axial loads (700 N, 1,400 N, 2,100 N, and 2,800 N) were applied to compute equivalent plastic strain volumes in the femoral head region; displacement-controlled loading was applied to failure to derive load-displacement curves for stiffness and the maximum failure load. Nail-tract vBMD and regional hip vBMDs were measured by quantitative CT. Pearson correlation analysis was conducted to investigate the associations of age and nail-tract vBMD with the aforementioned mechanical indicators. Results:Under the same load, compared with the 55-year-old, 65-year-old, and 75-year-old groups, the plastic strain unit volumes of the fracture models in the 85-year-old and 95-year-old groups increased significantly. Under a load of 700 N, no plastic strain was observed in the fracture models in the 55-year-old, 65-year-old, and 75-year-old groups, while an average plastic strain of approximately 50 mm 3 was observed in the fracture models in the 85-year-old group. Under a load of 2,800 N, the high strain areas in the fracture models in the 85-year-old and 95-year-old groups were mainly concentrated at the tip of the head nail and the junction between the head nail and the main nail. Load-displacement curves showed a marked reduction in the failure load in patients aged ≥85 years. Under loads of 1,400 N, 2,100 N, and 2,800 N, there was a strong association between the nail-tract vBMD and the volume of the plastic strain unit ( r=-0.82, -0.88, -0.89, respectively), which was stronger than those for total-hip vBMD. Conclusions:Finite-element analysis indicates that age and nail-tract vBMD are closely related to local plastic strain and overall stiffness of the proximal femur after PFNA-Ⅱ fixation for the geriatric intertrochanteric fractures. Patients aged ≥85 years old are more prone to plastic yielding, which compromises fixation stability.
