Medial knee joint loading during stair ambulation and walking while carrying loads

Area of Science:

• Biomechanics
• Orthopedics
• Kinetics

Background:

• Knee osteoarthritis (OA) is linked to elevated external knee adduction moment (KAM) during walking.
• Understanding how stair negotiation and load carrying affect KAM is crucial for OA management.

Purpose of the Study:

• To investigate the impact of different motion types (walking, stair ascent, stair descent) and load conditions on peak KAM.
• To quantify the changes in KAM during these activities in healthy individuals.

Main Methods:

• Sixteen healthy participants underwent 3D gait analysis.
• KAM was measured during walking, stair ascent, and stair descent under no load, front load, and backpack load conditions (13.6kg each).

Main Results:

• Both motion type and load significantly affected peak KAM (p<0.001).
• Stair ascent produced approximately double the peak KAM compared to stair descent and higher KAM than walking.
• Carrying loads significantly increased KAM compared to no-load conditions.

Conclusions:

• Carrying a moderate load during stair climbing substantially elevates peak KAM.
• Increased KAM during loaded stair negotiation may represent a significant risk factor for developing or exacerbating knee osteoarthritis.