Variability in Bilateral Femoro-Tibial Leg Rotation: CT Analysis of 105 Healthy Adults

Overview

This study analyzed bilateral femoral and tibial rotational alignment in 105 healthy adults using CT angiography. Significant intra-individual side-to-side differences were identified, highlighting the variability in normal lower limb rotation. The findings provide valuable reference values to improve assessment of axial-plane deformities in clinical practice.

Background

Rotational malalignment of the lower limb can arise from congenital or acquired conditions, including fractures treated with intramedullary nailing. Accurate reconstruction of femoral and tibial rotation is challenging due to limited bony landmarks, and malalignment may lead to functional impairment and knee disorders. CT-based imaging is the standard for assessing axial rotational alignment, typically comparing the affected limb to the contralateral side. However, individual side-to-side differences in healthy subjects are not well characterized, which may lead to misjudgment in clinical evaluation.

Data Highlights

Key Findings

• Significant side-to-side differences exist in femoral, tibial, and overall lower leg rotation among healthy individuals.
• Femoral anteversion was measured relative to the posterior condylar line, with positive values indicating internal rotation.
• Tibial torsion was assessed by the angle between proximal tibial condyles and the bimalleolar axis.
• Contralateral limbs cannot be assumed to be perfectly symmetrical in rotational alignment.
• Current clinical thresholds allowing up to 15° rotational difference may not account for normal physiological variability.

Clinical Implications

Clinicians should consider inherent bilateral variability in femoro-tibial rotation when evaluating suspected rotational deformities. Using contralateral limb measurements as the sole reference may lead to misinterpretation. The provided reference values from healthy subjects can aid in more accurate diagnosis and surgical planning, particularly in fracture management and deformity correction.

Conclusion

This study establishes normative data demonstrating significant bilateral variability in femoral and tibial rotation among healthy adults. Incorporating these findings into clinical practice can enhance the assessment and treatment of lower limb rotational deformities.

References

1. Folinais et al. -- Measurement of Femoral and Tibial Rotation
2. Reikerås and Høiseth -- Femoral and Tibial Torsion Assessment
3. Liodakis et al. -- Validation of Rotational Measurement Techniques
4. Hernandez et al. -- Definition of Femoral Neck Axis