Three-dimensional assessment of lower limb alignment: Reference values and sex-related differences

Area of Science:

• Orthopedic surgery
• Biomechanical analysis
• Medical imaging

Background:

• Three-dimensional (3D) preoperative planning is increasingly utilized in orthopedic surgery, particularly for deformity correction and joint replacement.
• Standardized reference ranges for 3D lower limb alignment are currently lacking, hindering precise preoperative planning and analysis.

Purpose of the Study:

• To establish reference ranges for three-dimensional (3D) lower limb alignment parameters.
• To identify and quantify sex-related differences in lower limb alignment.

Main Methods:

• Analysis of 60 three-dimensional (3D) bone models derived from computed tomography (CT) scans of lower limbs.
• Assessment of fifteen alignment parameters per leg using validated 3D analysis techniques.
• Generation of reference values based on mean and standard deviation, with evaluation of sex-based differences.

Main Results:

• Significant sex-related differences were observed in the mechanical lateral distal femoral angle, joint line convergence angle, hip knee ankle angle, and femoral torsion.
• Women exhibited a tendency towards valgus alignment, while men showed a tendency towards varus alignment.
• No significant sex differences were found in the medial proximal tibial angle or mechanical axis deviation.

Conclusions:

• This study provides comprehensive, sex-specific reference ranges for lower limb alignment parameters in three dimensions (3D).
• Acknowledging sex-related variations in alignment is essential for accurate analysis and effective surgical planning in orthopedic procedures.