Biomechanical Behavior of Dynamic vs. Static Distal Locking Intramedullary Nails in Subtrochanteric Femur Fractures

Area of Science:

• Orthopedic surgery
• Biomechanical engineering
• Trauma care

Background:

• Hip fractures, particularly subtrochanteric fractures, are common emergencies.
• Optimal treatment selection for these fractures is crucial for patient outcomes.

Purpose of the Study:

• To identify the best indications and techniques for subtrochanteric fractures.
• To establish criteria for selecting the most suitable intramedullary nail.

Main Methods:

• Finite Element Method (FEM) simulation was used.
• A femur model with a subtrochanteric fracture was stabilized with a long Gamma intramedullary nail.
• The influence of nail material (titanium) and distal locking type (static vs. dynamic) was analyzed.

Main Results:

• Titanium nails demonstrated greater micromobility at the fracture site, potentially aiding callus formation and consolidation.
• Distal locking type primarily influenced fracture site mobility and stress on cortical bone around screws.
• Observed mobility and stress levels did not compromise assembly viability or hinder fracture consolidation.

Conclusions:

• Treatment of subtrochanteric fractures with titanium nails and static distal locking is a safe option.
• This approach does not impede the bone consolidation process.