A Scientific Proposal for Surgical Decision-Making in Occult Intertrochanteric Fractures Based on Finite Element...

Area of Science:

• Biomechanics
• Orthopedic Surgery
• Computational Modeling

Background:

• Treatment consensus for isolated greater trochanteric and insufficient intertrochanteric fractures remains unclear.
• Limited patient numbers and MRI assessment challenges hinder treatment strategy development.
• Finite element (FE) analysis can elucidate fracture extension risks under various loads.

Purpose of the Study:

• To analyze stress distribution at the fracture line of insufficient intertrochanteric fractures using FE analysis.
• To investigate the influence of different loading conditions on fracture extension.
• To provide evidence-based support for surgical interventions.

Main Methods:

• A proximal femur FE model was generated from CT scan data.
• Two models were created: healthy proximal femur (HF) and femoral insufficient intertrochanteric fracture (FIF).
• Von Mises stress analysis was performed under simulated walking (3 W) and reduced weight-bearing (1/3 W) conditions with varying hip flexion angles (0°, 15°, 23°).

Main Results:

• The FIF model showed significantly elevated stress at the posterior fracture line during 3 W loading, indicating potential extension.
• Stress-induced element destruction (yielding) was observed in cortical and cancellous bone of the FIF model under 3 W loading.
• Minimal stress elevation and no yielding occurred in either model under 1/3 W loading, irrespective of flexion angle.

Conclusions:

• Elevated stress at the fracture line in the FIF model during walking suggests a higher risk of extension, especially with hip flexion.
• Reduced weight-bearing conditions appear to mitigate fracture extension risk by keeping stress within yield limits.
• Findings support surgical protocols that emphasize patient compliance with weight-bearing restrictions.