Knee alignment differences between Chinese and Caucasian subjects without osteoarthritis

Area of Science:

• Orthopedics
• Osteoarthritis Research
• Biomechanical Engineering

Background:

• Osteoarthritis (OA) prevalence varies across ethnic groups, with higher rates of lateral tibiofemoral OA in Chinese communities despite lower obesity.
• Obesity is a known risk factor for OA, suggesting other factors influence disease distribution.

Purpose of the Study:

• To investigate differences in knee alignment indices between Chinese and Caucasian populations.
• To determine if variations in knee morphology contribute to the observed ethnic differences in OA prevalence.

Main Methods:

• Analysis of knee radiographs from the Framingham Osteoarthritis Study (Chinese) and Beijing Osteoarthritis Study (Caucasian) cohorts.
• Measurement of anatomic axis (AA), condylar angle (CA), tibial plateau angle, and condylar-plateau angle (CP) in individuals without knee OA.
• Comparison of alignment indices between groups using linear regression, adjusting for age and BMI, stratified by sex.

Main Results:

• Significant differences in mean AA, CA, and CP were observed between Chinese (BOA) and Caucasian (FOA) participants.
• Chinese women showed significantly more valgus AA and CA.
• Chinese men exhibited significantly more valgus AA and CP.

Conclusions:

• Distinct knee morphology exists between Chinese and Caucasian populations, characterized by more valgus distal femur alignment in Chinese individuals.
• This valgus alignment shifts mechanical loading to the lateral knee compartment.
• The findings provide a potential explanation for the higher prevalence of lateral tibiofemoral OA in Chinese communities.