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DOI: 10.1055/s-0044-1782092
Finite Element Analysis Investigating the Impact of Positive Reduction on Femoral Neck Fracture
Introduction: Achieving an anatomic reduction is paramount in the management of femoral neck fractures (FNFs), but can be challenging in certain cases. The concept of 'Gotfried positive reduction' represents an alternative strategy for addressing such complexities. This technique involves positioning the distal femoral neck fragment at the inferior medial edge of the proximal fragment in the anteroposterior (AP) view. However, it is noteworthy that in certain clinical scenarios, augmenting the Gotfried positive reduction may lead to internal fixator failure and potentially induce hip varus.The aim of this study is to analyze the effect of Gotfried's positive reduction on the FNF with different Pauwels angles.
Methode: 3D models representing negative, anatomic, and positive femoral neck fracture (FNF) reductions stabilized with dynamic hip screws (DHS) and cannulated screws (CS), each associated with different Pauwels groups (Types I, II, and III), were generated based on CT data. A 2100N load was applied to the femoral head in alignment with the mechanical axis of the femur. The peak von Mises stress, displacement and peak von Mises strain were investigated. The peak von Mises stress distribution of the internal fixation was chosen as the key indicator to assess stability.
Results: The anatomic reduction model showed the minimum peak von Mises stress of the internal fixator for three groups (68.487 MPa, 98.991 MPa, and 161.11 MPa). With increasing positive reduction, there was a proportional increase in von Mises stress within the internal fixation. For Pauwels type I and type II, positive reductions of 1 mm (86.042 MPa, 115.3 MPa) and 2 mm (108.77 MPa, 151.7 MPa) were considered acceptable. For Pauwels type III, a positive reduction of 1 mm (167.9 MPa) was acceptable. Negative reduction should be avoided.
Discussion: Excessive positive reduction may increase the risk of internal fixation failure in FNF.
Keywords: Femoral neck fracture, Positive reduction, Finite element analysis
Korrespondenzadresse: XIANG ZHOU, Georg-August-University of Göttingen, Department of Trauma, Orthopedics and Reconstructive Surgery, Department of Trauma, Orthopedics and Reconstructive Surgery, Robert-Koch-Str.38/APP.1013 37075 Nied, 37075 Göttingen, Germany, E-Mail: xiang.zhou01@stud.uni-goettingen.de
Publication History
Article published online:
13 March 2024
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