Optimizing Reduction Guide Stability in Osteotomy Using Patient-Specific Instrumentation: A Basic Guideline

Area of Science:

• Orthopaedic Surgery
• Biomechanical Engineering
• Medical Device Design

Background:

• Patient-specific instruments (PSIs) are increasingly used in orthopaedic surgery for osteotomies to correct deformities.
• Intraoperative deformation of PSI reduction guides can compromise procedural accuracy.

Purpose of the Study:

• To analyze design parameters influencing intraoperative stability of PSI reduction guides using finite element analysis (FEA).

Main Methods:

• FEA was employed to evaluate a simplified PSI reduction guide with varying width, height, profile design, and K-wire slot configurations.
• Bending and torsional moments were applied to simulate intraoperative forces, measuring guide deformation and stress.

Main Results:

• Increasing guide profile height by 25% reduced bending deformation by 44% and torsional deformation by 37%.
• A 25% increase in profile width decreased bending deformation by 18% and torsional deformation by 22%.
• Transverse K-wire slots reduced torsional deformation by 51% compared to longitudinal slots; closer K-wire placement reduced bending and torsional deformation.

Conclusions:

• Increasing reduction guide height and reducing the central K-wire distance to the osteotomy are the most effective strategies for enhancing intraoperative stability.
• Guide design recommendations vary by osteotomy type: high-profile guides with longitudinal K-wire slots for bending-dominant procedures, and transverse slots for rotational osteotomies.