Load Distribution at the Patellofemoral Joint During Walking

Area of Science:

• Biomechanics
• Computational modeling
• Knee joint mechanics

Background:

• Understanding patellofemoral (PF) joint load distribution is crucial for treating PF disorders.
• Previous studies lacked detailed analysis of load sharing between medial and lateral patellar facets during dynamic activities like walking.

Purpose of the Study:

• To describe and explain the distribution of load across the medial and lateral patellar facets during normal walking.
• To identify the contributions of individual knee muscles to patellofemoral contact forces.

Main Methods:

• Developed a 13-segment, 32-degree-of-freedom (DOF) musculoskeletal model with a 12-DOF knee joint model.
• Incorporated deformable articular cartilage surfaces and validated model responses against cadaver data and biplane X-ray imaging.
• Calculated joint motion, contact trajectories, and forces during normal walking.

Main Results:

• The lateral patellar facet experienced considerably higher forces than the medial facet throughout the gait cycle.
• Quadriceps muscle forces, particularly from vastus lateralis, vastus intermedius, and rectus femoris, were primary drivers of higher lateral patellar contact forces.
• Specific muscle contributions were identified for distinct peaks in PF contact force during stance and swing phases.

Conclusions:

• Individual knee muscle contributions to patellofemoral load distribution are significant.
• Higher lateral patellar forces are mainly attributed to quadriceps muscle action.
• This detailed understanding may inform improved surgical and physiotherapy interventions for PF disorders.