Femoral version: Comparison among advanced imaging methods.

Area of Science:

• Orthopaedic Surgery
• Medical Imaging
• Biomechanical Analysis

Background:

• Accurate femoral version measurement is vital for surgical planning in lower extremity deformities.
• The optimal imaging modality and technique for assessing femoral version remain debated.
• Existing methods include 2D CT, MRI, and biplanar radiography, with varying sectional approaches.

Purpose of the Study:

• To compare the accuracy of femoral version measurements using 2D CT, 2D MRI, and 3D biplanar radiography against a 3D CT model.
• To evaluate differences in femoral version measurements between axial and oblique sections of the proximal femur for CT and MRI.

Main Methods:

• Eight adult cadaver lower extremities were scanned using CT, MRI, and biplanar radiography.
• Femoral version was measured from axial and oblique CT/MRI slices and biplanar radiography reconstructions.
• Measurements were compared to a 3D CT-derived model.

Main Results:

• All five tested techniques (2D CT axial/oblique, 2D MRI axial/oblique, biplanar radiography) showed excellent correlation with the 3D CT model (r > 0.81).
• All techniques slightly underestimated femoral version compared to the 3D model, but differences were not statistically significant.
• Oblique CT and MRI slices yielded slightly greater femoral version measurements (5.4° and 1.4°, respectively) than axial slices.

Conclusions:

• Multiple imaging modalities (CT, MRI, biplanar radiography) provide accurate femoral version measurements.
• The choice of imaging modality can be individualized based on patient factors rather than solely on measurement accuracy.
• Utilizing femoral neck oblique slices in CT and MRI may offer slightly more precise measurements.