Thigh-calf contact force measurements in deep knee flexion

Area of Science:

• Biomechanics
• Orthopedics
• Human Movement Analysis

Background:

• Knee models often neglect thigh-calf contact during deep knee flexion.
• This contact is hypothesized to reduce muscle forces and alter internal knee joint stresses.

Purpose of the Study:

• To quantify thigh-calf contact forces during deep knee flexion activities.
• To investigate the influence of squatting and kneeling on these forces.

Main Methods:

• Ten healthy subjects underwent measurements of thigh-calf contact pressures using Tekscan sensors.
• Knee flexion angles were tracked using infrared motion capture.
• Contact forces were averaged, and correlations with anthropometric data were analyzed.

Main Results:

• Thigh-calf contact typically initiated below 130 degrees of knee flexion.
• Average maximal contact forces reached 34.2% bodyweight (squatting) and 30.9% bodyweight (kneeling).
• Contact forces correlated with thigh and calf circumferences.

Conclusions:

• Substantial thigh-calf contact occurs during deep knee flexion, potentially reducing internal knee joint loads.
• This finding may imply lower loads on total knee replacements, reducing failure risks.
• Results are valuable for refining knee models simulating deep flexion.