Femoral anteversion in the hip: comparison of measurement by computed tomography, magnetic resonance imaging, and physical examination
Authors
Botser IB, Ozoude GC, Martin DE, Siddiqi AJ, Kuppuswami S, Domb BG
DOI: 10.1016/j.arthro.2011.10.021
Purpose
To assess the correlation between femoral anteversion measurements using CT and MRI, and to evaluate the relationship between anteversion and physical examination or radiographic findings.
Methods
129 hips undergoing preoperative CT, MRI, and clinical exams were analyzed. Anteversion was measured by two musculoskeletal radiologists. Patients were divided into low, medium, and high anteversion groups to compare findings across modalities and with physical exams.
Key Findings
- CT and MRI correlated strongly (r = 0.80), but CT consistently showed higher anteversion (mean difference of 8.9°).
- CT had better interobserver reliability than MRI.
- Internal hip rotation correlated with CT anteversion (r = 0.36).
- Cam impingement was more common with low anteversion; pincer impingement with high anteversion.
Conclusion
Although CT and MRI correlate well, their absolute values differ, meaning they shouldn’t be used interchangeably. CT is more reliable for measuring femoral anteversion and better correlates with clinical internal rotation.
What this means for patients
If your surgeon is assessing your femoral rotation to guide treatment, CT scans may provide more accurate and consistent information than MRI or physical exams alone.