Body mass index moderates the association between gait kinetics, body composition, and femoral knee cartilage characteristics

Abstract

This study compared femoral cartilage characteristics between age‐ and sex‐matched individuals with (n=48, Age=22.8±3.5 years; BMI=33.1±4.1 kg/m²) and without obesity (n=48 Age=22.0±2.6 years; BMI=21.7±1.7 kg/m²) and evaluated the associations between body composition, quadriceps function, and gait kinetics with femoral cartilage characteristics. Medial and lateral femoral cartilage thickness, medial:lateral thickness ratio, and medial and lateral cartilage echo intensity were measured using ultrasound imaging. Body composition was assessed using air displacement plethysmography. Quadriceps function was assessed via maximal isometric knee extension. Three‐dimensional gait biomechanics were recorded to extract peak external knee flexion and adduction moments, and peak loading rate of the vertical ground reaction force. Cartilage outcomes were compared between groups using one‐way MANOVA. Stepwise moderated regression evaluated the association between body composition, quadriceps function, and gait kinetics with femoral cartilage outcomes in individuals with and without obesity. Medial (75.24 vs. 65.84; p2=0.09–0.12) in individuals with obesity. A higher knee adduction moment was associated with a larger medial:lateral thickness ratio (ΔR²=0.09) in individuals without obesity. No associations were found between quadriceps function and cartilage outcomes. These findings suggest that high body fat in adults with obesity is associated with cartilage echo intensity. Obese BMI was also associated with a lack of a positive relationship between cartilage thickness and joint loading during walking.