Flexure-Based Locking Plates Can Modulate Interfragmentary Motion in Distal Femur and Diaphyseal Fractures: A...

Area of Science:

• Orthopedic biomechanics
• Biomaterials engineering
• Computational modeling

Background:

• Axial interfragmentary motion is crucial for stimulating fracture healing.
• Current rigid fixation plates may limit this essential motion.
• Developing mechanically compliant fixation is a potential strategy to optimize fracture healing.

Purpose of the Study:

• To computationally model and assess the feasibility of a novel compliant fracture fixation plate designed to provide controlled axial micromotion.
• To compare the performance of compliant plates against traditional rigid plates for diaphyseal and distal femur fractures.

Main Methods:

• Finite element analysis (FEA) was employed to model diaphyseal and distal femur fractures with both rigid and compliant fixation plates.
• A FEA model for compliant plates was validated against experimental data.
• Parametric analysis was conducted on compliant plate designs with varying geometry and materials.

Main Results:

• Compliant plates generated significantly greater and more symmetric axial interfragmentary motion (1.03 mm vs. 0.22 mm) than rigid plates under axial loading.
• Steel compliant plates with thicker flexures (0.3-0.6 mm) showed promising performance with enhanced motion and adequate rigidity.
• For distal femur fractures, compliant plates modulated interfragmentary motion, increasing near cortex motion under low loads and decreasing far cortex motion under high loads.

Conclusions:

• Flexure-based compliant plates represent a promising advancement for treating diaphyseal and distal femur fractures by optimizing interfragmentary motion.
• These novel plates offer a potential improvement over rigid fixation by providing controlled micromotion essential for fracture healing.
• Further in vivo investigation is warranted to confirm the clinical efficacy of these compliant fixation systems.