A Novel Approach to Lower-limb Axial Alignment Analysis: A CT Study.

Area of Science:

• Orthopedics
• Biomechanics
• Anatomy

Background:

• Lower extremity torsion is a critical factor in joint function and alignment.
• Understanding the specific contributions of femur and tibia segments to overall torsion is essential for diagnosing and treating related conditions.

Purpose of the Study:

• To analyze lower extremity torsion in a healthy cohort.
• To determine the specific contributions of different femur and tibia segments to overall lower limb torsion.

Main Methods:

• A cross-sectional study involving 32 healthy patients.
• CT angiography was used to measure lower limb, femoral, and tibial torsion, including specific segment contributions (proximal, shaft, distal).

Main Results:

• Median total lower limb torsion was 25° external.
• Femoral torsion was -9° (internal), with proximal and distal metaphyses showing internal torsion, compensated by external torsion in the femoral shaft.
• Tibial torsion was 30° (external), with the proximal metaphysis contributing one-third and the diaphysis/distal segment contributing two-thirds.

Conclusions:

• The diaphysis and distal metaphysis are the primary contributors to external tibial torsion.
• The proximal metaphysis is the main contributor to internal femoral torsion.