Quantitative analysis of protective Kirschner wire diameters in lateral opening wedge distal femoral osteotomy: A finite element study
Alican Baris1
, Emre Özmen1, Esra Circi1, Serdar Yuksel1, Ozan Beytemür2
1Department of Orthopedics and Traumatology, İstanbul Physical Medicine and Rehabilitation Training and Research Hospital, İstanbul, Türkiye
2Department of Orthopedics and Traumatology, Bağcılar Training and Research Hospital, İstanbul, Türkiye
Keywords: Biomechanics, distal femoral osteotomy, finite element analysis, hinge fracture, protective K-wire.
Abstract
Objectives: This study aims to investigate quantitatively the protective effect of a 1.6-mm or a 2.5-mm Kirschner wire (K-wire) on the medial hinge at different gap distances through finite element analysis (FEA) and to establish whether using a 2.5-mm K-wire can offer benefits compared to a 1.6-mm in preventing medial hinge fractures.
Materials and methods: Between June 2024 and July 2024, three different models simulating a lateral opening wedge (LOW) osteotomy of the distal femur were created from a femoral computed tomography (CT) scan of a 36-year-old male patient: no K-wire (Model I), 1.6-mm K-wire (Model II), and 2.5-mm K-wire (Model III). Finite element analysis was performed to simulate 7- to 13-mm gaps at the osteotomy site. Loads, principal stress, strain, and equivalent stress were analyzed around the medial hinge.
Results: Model I required 123.0±5.2 N, Model II required 181.7±12.2 N, and Model III required 228.7±13.6 N (p<0.001). Cracked shell elements were the lowest in Model II and the highest in Model I. While the average equivalent/yield stress ratio was not significantly lower in Model II compared to Model III (87.0±10.9% vs. 92.7±12.1%), the maximum equivalent/yield stress ratio values in Model II were significantly lower than both Model I and Model III (1206.2±138.3% vs. 1836.2±165.4% and 1689.1±404.0%, respectively), suggesting a superior dispersion of forces.
Conclusion: Using a 1.6-mm K-wire during LOW osteotomy of the distal femur provides a balance between structural reinforcement and stress distribution, significantly improving stability and reducing the risk of medial hinge fractures compared to a 2.5-mm K-wire or no K-wire. The 1.6-mm K-wire optimizes stress dispersion, making it the preferred choice for surgical planning in lateral opening wedge distal femoral osteotomy.
Citation: Baris A, Özmen E, Circi E, Yuksel S, Beytemür O. Quantitative analysis of protective Kirschner wire diameters in lateral opening wedge distal femoral osteotomy: A finite element study. Jt Dis Relat Surg 2025;36(1):i-x. doi: 10.52312/ jdrs.2025.1806.