Finite element analysis of the influence of intra-articular impacted fragment area and volume on joint contact stress in ankle fractures
10.3760/cma.j.cn121113-20241031-00608
- VernacularTitle:踝关节骨折中关节面嵌入骨块面积和体积对关节面接触应力影响的有限元分析
- Author:
Wenyong XIE
1
;
Qingpeng SONG
1
;
Yuan LIU
1
;
Qing LIU
1
;
Jian LIU
1
;
Guanglei CAO
1
;
Ye HUANG
1
Author Information
1. 首都医科大学附属北京积水潭医院保膝外科，北京 100035
- Publication Type:Journal Article
- Keywords:
Finite element analysis;
Ankle fractures;
Intra-articular Fractures;
Stress, mechanical
- From:
Chinese Journal of Orthopaedics
2025;45(16):1066-1071
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To explore the effect of the defect area and volume of intra-articular impacted fragments (IAIF) on the contact stress of the ankle joint surface.Methods:A 23-year-old male volunteer, 168 cm in height and 60 kg in weight, with no history of trauma or anatomic abnormality of the ankle, was selected. On the basis of a normal ankle finite-element model, IAIF-defect finite-element models were established. The first group consisted of IAIF-defect models with identical area but different volumes: on the distal tibial articular surface the defect area was 4 mm × 5 mm (20 mm 2), and the heights were 2 mm, 3 mm, 4 mm, 5 mm and 6 mm. The second group consisted of IAIF-defect models with identical defect volume but different areas. The defect volume was 90 mm 3, while the defect areas on the distal tibial articular surface were 2 mm×3 mm, 3 mm×3 mm, 3 mm×5 mm, 3 mm×6 mm, and 5 mm×6 mm, with corresponding heights of 15 mm, 10 mm, 6 mm, 5 mm, and 3 mm. Under a 600 N vertical load the contact stress of the ankle joint was calculated, and the finite-element data were recorded and analyzed. Pearson correlation analysis was used to analyze, separately for the two groups, the correlation between IAIF defect and the maximum contact stress (MCS) of the distal tibial articular surface, and simple linear regression analysis was performed to obtain regression equations. Equivalence zero testing was used to verify the correlations and to compare their differences. Results:For IAIF defects with the same area but different volumes, including 4 mm×5 mm×2 mm, 4 mm×5 mm×3 mm, 4 mm×5 mm×4 mm, 4 mm×5 mm×5 mm, and 4 mm× 5 mm×6 mm, the corresponding maximum contact stress (MCS) on the distal tibial joint surface were 3.846 MPa, 3.839 MPa, 3.835 MPa, 3.833 MPa, and 3.831 MPa, respectively, with an average of 3.837 MPa. The mean ±1% range is from 3.799 MPa to 3.875 MPa. The correlation analysis showed that the IAIF defects with the same area but different volumes were negatively correlated with contact stress ( r=-0.956, P=0.011). The linear regression equation was MCS=-0.0002×VI+3.851, where VI denotes IAIF volume. Equivalence zero testing confirmed that all measured values lay within the predefined ±1 % margin, satisfying the equivalence null hypothesis. For IAIF defects of identical volume (90 mm 3) but varying articular surface areas—2 mm×3 mm, 3 mm×3 mm, 3 mm×5 mm, 3 mm×6 mm and 5 mm×6 mm—the corresponding MCS values were 2.147 MPa, 2.812 MPa, 3.622 MPa, 4.476 MPa and 6.186 MPa, respectively (mean 3.849 MPa; equivalence band 3.811-3.887 MPa at ±1% of the mean). Correlation analysis demonstrated a strong positive relationship between identical-volume varying-area IAIF defects and contact stress ( r=0.996, P<0.001). The linear regression equation was MCS=0.168×AI+1.236, where AI denotes IAIF area. Equivalence zero testing indicated that none of the measured values fell within the predefined ±1% margin, failing to satisfy the equivalence null hypothesis. Conclusion:In posterior ankle fractures, the volume change of IAIF defects has no clinical significance in relation to MCS, showing a small negative correlation. However, the area change of IAIF defects is clinically significant in relation to MCS, demonstrating a larger positive correlation.
