A computer aided measurement method for unstable pelvic fractures based on standardized radiographs

Area of Science:

• Orthopedic Surgery
• Radiology
• Medical Imaging Analysis

Background:

• Unstable pelvic ring fractures require precise displacement measurement for effective treatment.
• Standardized radiographic assessment is crucial for surgical planning and outcomes.
• Existing methods may lack the reliability and precision needed for complex fractures.

Purpose of the Study:

• To develop and validate a novel method for quantifying radiographic displacement in unstable pelvic ring fractures.
• To assess the reliability and validity of this software-based measurement technique.
• To establish a standardized approach for describing pelvic fracture displacement.

Main Methods:

• Simulated standardized X-ray images (inlet, outlet, AP) from CT data of 25 patients with AO/OTA type B or C pelvic fractures.
• Developed a formula to calculate translational and rotational displacement using 2D coordinates from digitized X-rays.
• Assessed interobserver reliability using intraclass correlation coefficient (ICC) and kappa statistics, comparing the formula method with 3D CT reconstruction and surgeon's overall impression.

Main Results:

• The formula-based method demonstrated high interobserver reliability for both translational and rotational measurements (ICCs > 0.9).
• Rotational outcome measurements using the new method perfectly matched those from 3-matic software.
• The agreement among surgeons for rotational outcome based on overall impression was poor (kappa: 0.250–0.426).

Conclusions:

• The developed formula-based method is a reliable tool for measuring pelvic fracture displacement.
• This technique minimizes measurement errors and enhances the precision of pelvic fracture descriptions.
• The method provides a foundation for standardizing operative plans and potentially guiding robot-assisted pelvic fracture surgery.