Knee adduction moment decomposition: Toward better clinical decision-making

Area of Science:

• Biomechanics
• Orthopedics
• Gait Analysis

Background:

• Knee adduction moment (KAM) progression is linked to medial knee osteoarthritis (OA).
• Generic gait modifications may not reduce KAM effectively for all patients.
• Understanding KAM components is crucial for targeted interventions.

Purpose of the Study:

• Introduce the "decomposed ground reaction vector" (dGRV) model to analyze KAM components.
• Investigate the influence of medial knee OA, gait speed, and bracing on KAM components.
• Provide a basis for personalized gait rehabilitation in knee OA.

Main Methods:

• Calculated KAM using inverse dynamics as a reference.
• Applied the dGRV model to healthy participants and knee OA patients under various conditions (brace, speed).
• Analyzed four distinct KAM components derived from ground reaction force and lever arms.

Main Results:

• The dGRV model accurately predicted KAM profiles (R²=0.98).
• The second KAM component, a major contributor to increased KAM in OA, was reduced by bracing in healthy individuals.
• Increased walking speed elevated the first KAM peak and decreased KAM impulse, with no significant change in the second peak.

Conclusions:

• The dGRV model successfully quantifies KAM components across different conditions.
• The model explains variability in patient responses to gait modifications.
• Personalized rehabilitation targeting specific KAM components is a promising approach for knee OA management.