Immediate effects of lateral wedge insoles on inter-joint coordination in women with knee osteoarthritis: A comparative study of footwear.

Abstract

Knee osteoarthritis is a degenerative condition characterized by pain and increased gait variability. Lateral wedge insoles are prescribed to reduce medial knee joint loading; however, their effects on lower-limb joint coordination variability, pain, and comfort when combined with different footwear remain unclear. This study examined lateral wedge insoles worn with conventional sandals and researcher-made slipper socks in women with knee osteoarthritis. A within-subject design was conducted with 23 women (aged 45-65) diagnosed with bilateral medial compartment knee osteoarthritis (Kellgren-Lawrence grades II and III). Participants walked barefoot, in sandals with lateral wedge insoles, and in slipper socks with lateral wedge insoles. Lower-limb inter-joint coordination was assessed using three-dimensional motion capture, and pain and comfort were evaluated using the Visual Analog Scale and Likert scale. Mann-Whitney U tests compared coordination variability, and Spearman correlations explored relationships between variability, pain, and comfort. Coordination mode distributions varied across gait subphases and footwear conditions, but no significant pairwise differences were observed. Slipper socks with lateral wedge insoles showed significantly lower coordination variability for hip-knee (P < 0.001) and knee-ankle (P = 0.04) coupling compared to sandals. Pain was negatively correlated with coordination variability in the sandal condition, while reduced variability in slipper socks was associated with lower pain and improved comfort. Lateral wedge insoles in sandals increased coordination variability and pain, while slipper socks reduced variability, improving comfort and pain outcomes. Footwear design plays a crucial role in optimizing gait stability and symptom management in knee osteoarthritis.