Normative Relationships Between Spinopelvic Alignment and Femoroacetabular Orientation: A Cross-Sectional Study

Area of Science:

• Orthopedics
• Biomechanical Engineering
• Radiology

Background:

• Detailed normative data on spinopelvic and femoroacetabular alignment is lacking.
• Understanding these relationships is crucial for orthopedic surgery and biomechanics.

Purpose of the Study:

• To investigate associations between femoroacetabular parameters (acetabular anteversion, acetabular inclination, femoral version) and spinopelvic parameters (pelvic incidence, pelvic tilt, lumbar lordosis) in healthy young adults.

Main Methods:

• Cross-sectional study of 395 healthy volunteers.
• Full body EOS scans used for 3D reconstructions of hips and spine.
• Multiple linear regression analyses to test associations between femoroacetabular and spinopelvic parameters.

Main Results:

• Acetabular anteversion (AA) was associated with pelvic incidence (PI), pelvic tilt (PT), age, sex, and weight (R² = 0.381).
• Acetabular inclination (AI) showed less variability but was associated with femoral version (FV), PT, age, height, and weight (R² = 0.0949).

Conclusions:

• Normative relationships between acetabular orientation and spinopelvic parameters were identified.
• Residual variability in AA suggests spinopelvic parameters alone do not fully predict it.
• Findings provide a basis for understanding age-related alignment changes and guiding surgical restoration in THA and spinal fusion.