Patellofemoral Joint Contact Area Quantified In Vivo During Daily Activities

Area of Science:

• Biomechanics
• Orthopedics
• Human Movement Analysis

Background:

• In vivo patellofemoral joint contact area measurements are limited, especially during dynamic activities.
• Previous studies primarily focused on static knee conditions.

Purpose of the Study:

• To measure and compare patellofemoral joint contact area in healthy individuals during various daily activities.
• To investigate the influence of knee flexion angle and activity type on patellofemoral contact area.

Main Methods:

• Utilized mobile biplane X-ray imaging for 3D tibiofemoral and patellofemoral kinematics.
• Combined kinematic data with magnetic resonance imaging to determine patellofemoral contact area.
• Assessed activities including level walking, downhill walking, stair ascent/descent, and open-chain knee movements.

Main Results:

• Knee flexion angle explained a significant portion of the variability in total (83%), lateral (80%), and medial (72%) patellofemoral contact areas.
• Patellofemoral contact areas increased up to 60° flexion and then decreased, with less sensitivity to activity type.
• Lateral patellofemoral contact area was consistently larger than the medial contact area across all activities (p < 0.001).

Conclusions:

• Knee flexion is a primary determinant of in vivo patellofemoral contact area during dynamic activities.
• Understanding these contact areas aids in comprehending patellofemoral joint biomechanics.
• Findings can help validate computational models of the patellofemoral joint.