Effect of fracture level on optimal Kirschner wire configuration in pediatric supracondylar humerus fractures: A finite element analysis

Turkay Yilmaz; Ismail Hakki Dur; Tugce Kabakci; Muhammed Abdulkadir Bulut; Bengu Akgok; Ulas Can Kolac; Mustafa Ozkaya; Sancar Bakircioglu

doi:10.52312/jdrs.2025.2248

Turkay Yilmaz¹, Ismail Hakki Dur², Tugce Kabakci², Muhammed Abdulkadir Bulut³, Bengu Akgok², Ulas Can Kolac³, Mustafa Ozkaya⁴, Sancar Bakircioglu⁵

¹Department of Orthopedics and Traumatology, Alaca State Hospital, Çorum, Türkiye
²TOBB University of Economy and Technology, Faculty of Medicine, Ankara, Türkiye
³Department of Orthopedics and Traumatology, Hacettepe University Faculty of Medicine, Ankara, Türkiye
⁴Department of Mechanical Engineering, KTO Karatay University, Konya, Türkiye
⁵Department of Orthopedics and Traumatology, TOBB University of Economy and Technology, Ankara, Türkiye

Keywords: Biomechanics, finite element, fracture level, fracture type, Kirschner-wire, pediatric elbow fractures, pin configuration, supracondylar humerus fractures.

Abstract

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.

Citation: Yilmaz T, Dur IH, Kabakci T, Bulut MA, Akgok B, Kolac UC, et al. Effect of fracture level on optimal Kirschner wire configuration in pediatric supracondylar humerus fractures: A finite element analysis. Jt Dis Relat Surg 2025;36(3):648-658. doi: 10.52312/jdrs.2025.2248.