A simple method to determine the pelvic inclination angle based on anteroposterior radiographs

Area of Science:

• Orthopedics
• Radiology
• Biomedical Engineering

Background:

• Pelvic inclination angle is crucial in hip biomechanics and surgical planning.
• Accurate measurement of pelvic inclination angle is often challenging with standard imaging.
• Existing methods may require specialized views or complex calculations.

Purpose of the Study:

• To introduce a straightforward method for calculating pelvic inclination angle.
• To validate the proposed formula using anteroposterior (AP) hip radiographs.
• To assess the reliability and reproducibility of the new measurement technique.

Main Methods:

• A trigonometric formula was derived to calculate pelvic inclination angle from AP radiographs.
• Measurements included pelvic foramen height (H) and pelvic foramen distance (D).
• Two formulas were tested: sin θ = H/D and sin θ = H/average pelvic foramen distance.

Main Results:

• A significant correlation was found between the calculated angle (θ1) and the measured angle (θ0) from lateral radiographs.
• Another significant correlation was observed between the two calculated angles (θ1 and θ2).
• The proposed formula demonstrated adequate reliability and reproducibility.

Conclusions:

• Pelvic inclination angle can be reliably estimated using a simple formula based on pelvic foramen height from AP radiographs.
• The developed method offers a practical and reproducible approach for clinical assessment.
• This technique simplifies the determination of pelvic inclination angle, aiding in surgical planning and patient management.