Dynamic trapezoid external fixation: Enhancing temporary stability in unstable pelvic ring fractures

Area of Science:

• Orthopedic biomechanics
• Trauma surgery
• External fixation devices

Background:

• Unstable pelvic fractures necessitate emergency external fixation before definitive internal fixation.
• Improving posterior pelvic ring stability during temporary fixation is crucial for patient outcomes.

Purpose of the Study:

• To evaluate if a temporary pelvic external fixator with dual compression and distraction bars enhances posterior pelvic stability.
• To determine the effectiveness of a dynamic trapezoid external fixator in stabilizing the pelvic ring.

Main Methods:

• Four supracetabular fixation setups, including a dynamic trapezoid external fixator, were tested on foam pelvis models with simulated sacroiliac disjunction.
• Biomechanical testing assessed stability under cranial and lateral traction forces, with varying supra-acetabular pin insertions.
• Statistical analysis, including Student's t-test and ANOVA, compared displacement across configurations.

Main Results:

• The dynamic trapezoid construct demonstrated the lowest sacroiliac displacement under both lateral and vertical forces.
• Fully inserted supra-acetabular pins significantly reduced displacement compared to partial insertion (p < 0.001).
• The dynamic construct and full pin insertion yielded the most stable outcomes (p < 0.0001).

Conclusions:

• A dynamic trapezoidal supra-acetabular external fixator with dual rods enhances resistance to pelvic SI joint displacement.
• This construct offers superior stability compared to other tested configurations.
• The findings support a streamlined approach to temporary pelvic stabilization in unstable pelvic fractures.