COUPLED 2025

Biomechanical Evaluation of a Novel Compression Pin Fixation for Distal Humerus Transcondylar Fractures Using Finite Element Modeling

  • Gomez, Mario (Embry-Riddle Aeronautical University)
  • Dhainaut, Jean-Michel (Embry-Riddle Aeronautical University)
  • Hidalgo, Victor (Escuela Politécnica Nacional)
  • Huffman, Russell (Rothman Orthopaedics Florida at AdventHealth)
  • Eygendaal, Denise (Erasmus Medical Center)
  • Kachooei, Amir (Rothman Orthopaedics Florida at AdventHealth)
  • Huayamave, Victor (Embry-Riddle Aeronautical University)

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Distal humerus fractures, particularly low lying fractures in the older adults with osteoporosis, present significant challenges due to limited bone real estate to accommodate the plate and screws and provide a rigid enough fixation to allow early mobilization. Drawbacks with the current osteosynthesis plate fixation is a risk of fixation failure despite an extensive dissection in this type of fractures. This study investigates a fixation method using compression pins, aiming to improve stability and prevent pin or screw backing-out in distal humerus transcondylar fractures. To evaluate the mechanical outcomes of this technique, a finite element model (FEM) was developed based on the anatomical geometry of the distal humerus from an 82-year-old male, representing the elderly population. Initial simulations, derived from this patient-specific model, assessed stress, strain, and inter-fragmentary displacement, revealing promising results within acceptable medical limits for fracture stability. The statistical shape model, which will represent a broader population, is still in progress, with the current work involving the creation of volumetric models using a database to develop the shape model. While the shape model is not yet finalized, the existing FEM allows for quick modifications of the geometry once the statistical shape model is obtained, ensuring that future simulations will be representative of a wider patient cohort. The FEM simulations aim to assess the biomechanical performance of the compression pin fixation, evaluating stress distribution, strain, and displacement under typical loading conditions to simulate the daily activities including getting up in an armchair. Preliminary findings suggests using one medial and two lateral compression pins with a diameter of 3.5mm transfixing the distal humerus fracture which can withhold the forces allowing early elbow range of motion and potentially reducing complications such as fixation failure and nonunion. If further validated, this fixation method could offer a significant advancement in the treatment of distal humerus fractures, especially for elderly patients, by providing a more reliable and effective solution. Long-term clinical trials will be necessary to establish the technique's effectiveness in improving patient outcomes and reducing recovery times. This study underscores the potential of computational models in refining surgical techniques and optimizing fracture management strategies.