Effect of fracture level on optimal Kirschner wire configuration in pediatric supracondylar humerus fractures: A finite element analysis
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Published on: August 14, 2018
Turkay Yilmaz, Ismail Hakki Dur, Tugce Kabakci
1TOBB ETÜ Ekonomi ve Teknoloji Üniversitesi, Ortopedi ve Travmatoloji Anabilim Dalı, 06510 Çankaya, Ankara, Türkiye. bakircioglusancar@gmail.com.
Insights
The best pin configuration for transverse supracondylar humerus fractures depends on the fracture level. Finite element analysis (FEA) shows varying stability for different pin setups in pediatric cases.
Area of Science:
- Orthopedic biomechanics
- Pediatric trauma surgery
- Finite element analysis in medicine
Background:
- Transverse supracondylar humerus fractures are common in children.
- Optimal fixation strategies are crucial for stable healing and minimizing complications.
- Previous studies have explored various pin configurations, but biomechanical data is limited.
Purpose of the Study:
- To evaluate and compare the biomechanical stability of three distinct pin configurations for transverse supracondylar humerus fractures.
- To analyze stability across different fracture levels (low, transolecranon, high, ultrahigh) using finite element analysis (FEA).
Main Methods:
- A pediatric humerus bone model was created from CT data.
- Four fracture levels and three pin fixation techniques (1-1M, 1-1C, 2-1C) were simulated.
- Translational and rotational stiffness were analyzed using FEA under various loading conditions.
Main Results:
- Pin configuration 1-1M offered highest stability in ultrahigh fractures under valgus load.
- Configuration 2-1C showed superior stability in low and transolecranon fractures for valgus/varus loading.
- Configuration 1-1M excelled in transolecranon/high fractures during extension/flexion, while 2-1C was better in low/ultrahigh fractures.
Conclusions:
- No single pin configuration is universally superior for all transverse supracondylar humerus fracture types.
- Fixation selection should be tailored to the specific fracture characteristics and level.
- FEA provides valuable insights into biomechanical stability for pediatric fracture management.
Objectives:
This study aims to evaluate the biomechanical stability of three pin configurations for transverse supracondylar humerus fractures at various levels using finite element analysis (FEA).
Materials And Methods:
Computed tomography data from a six-year-old child were used to generate a humerus bone model. Four different fracture levels (low, transolecranon, high, and ultrahigh) and three pin fixation techniques (one lateral and one medial cross-pin [1-1M], two lateral capitellar pins [1-1C], and three lateral capitellar pins [2-1C]) were designed for the study. Translational stiffness and rotational stiffness in all directions were analyzed in the mesh models. Convergence data and stiffness data were obtained in the FEA.
Results:
The translational and rotational stiffness values varied across fracture levels and pin configurations. Under valgus loading, the 1-1M configuration provided the highest stability in ultrahigh fractures (3289 N/mm), while the 2-1C configuration showed superior valgus and varus stability in low and transolecranon fractures. During extension and flexion loading, the 1-1M configuration yielded the highest stiffness values for transolecranon and high fractures, while the 2-1C configuration demonstrated increased stability in low and ultrahigh fractures. For rotational loading, 1-1M produced the highest inward and outward stiffness values in low-level fractures (9175 and 11035 N·mm/degree, respectively), whereas 2-1C displayed greater rotational stiffness in ultrahigh fractures.
Conclusion:
This preliminary study suggests that no single pin configuration is ideal for all fracture types, and the choice should be based on the specific fracture case.
