Gender-based differences exist in the functional knee phenotypes classification of the osteoarthritic knee

Area of Science:

• Orthopedics
• Biomechanical Engineering
• Radiology

Background:

• Osteoarthritis (OA) affects knee alignment, with varying phenotypes.
• Understanding gender-specific differences in knee morphology is crucial for personalized treatment.
• Previous research has not fully elucidated gender-based variations in coronal alignment and joint line convergence angle (JLCA) within OA phenotypes.

Purpose of the Study:

• To investigate gender-based disparities in coronal alignment of functional knee phenotypes.
• To analyze the joint line convergence angle (JLCA) in relation to specific knee phenotypes and gender.

Main Methods:

• Retrospective analysis of 12,099 knee CT scans (5025 male, 7074 female) with osteoarthritis.
• Utilized Medacta software to measure hip-knee-ankle angle (HKA), femoral mechanical angle (FMA), tibial mechanical angle (TMA), and JLCA.
• Data were categorized by gender and functional knee phenotypes.

Main Results:

• Identified 17 common phenotypes between genders out of 127 (male) and 131 (female) identified phenotypes.
• Commonest phenotypes showed similar HKA, FMA, and TMA values across genders.
• Males demonstrated significantly greater femoral varus compared to females (p < 0.001).
• Mean JLCA was -2.96° (SD ±2.6°) for males and -2.66° (SD ±2.87°) for females (p < 0.001).

Conclusions:

• Distinct gender differences exist in osteoarthritic knee phenotypes.
• Male varus phenotype is primarily influenced by femoral mechanical angle (FMA), while tibial mechanical angle (TMA) is similar across genders.
• JLCA variations correlate with both TMA and FMA, suggesting bone morphology is a key determinant, rather than gender alone.
• These findings aid in tailoring surgical strategies for primary total knee arthroplasty (TKA).