Intramedullary nail design for Thais with novel multi-femur shape optimization approach

Area of Science:

• Biomedical Engineering
• Orthopedic Surgery
• Computational Mechanics

Background:

• Intramedullary nails are standard for femoral fractures but often ill-suited for Asian populations due to anatomical differences.
• Current designs based on Caucasian anatomy can lead to increased stress and nail tip penetration in Asian femurs.

Purpose of the Study:

• To design a novel long intramedullary nail optimized for the Thai femoral medullary canal using a multi-femur shape optimization approach.
• To reduce stress on the femur and improve implant fit for the Thai population.

Main Methods:

• Analyzed 60 Thai femur CT scans, selecting ten representative femurs using k-means clustering.
• Modeled nail curvature with four circular arcs, optimizing radii using a multi-objective genetic algorithm (MOGA) in Ansys.
• Performed finite element analysis to compare stresses induced by the optimized nail versus commercial nails.

Main Results:

• The multi-femur shape optimized nail significantly reduced maximum principal stress in representative Thai femurs compared to commercial designs.
• Optimized nail design showed substantially lower stress under simulated physiological loading conditions.

Conclusions:

• A multi-femur shape optimization approach effectively designs intramedullary nails that better fit diverse femoral anatomies, specifically the Thai population.
• The optimized nail design offers a promising solution to reduce stress and improve outcomes in treating femoral fractures in Asian patients.