Altered loading in the injured knee after ACL rupture

Area of Science:

• Biomechanics
• Orthopedics
• Sports Medicine

Background:

• Articular loading is a key factor in joint degeneration following anterior cruciate ligament (ACL) rupture.
• Assessing joint loading in injured individuals requires models that account for individual muscle activation strategies.

Purpose of the Study:

• To evaluate knee joint contact forces in patients with ACL deficiency.
• To utilize an EMG-driven musculoskeletal modeling approach for estimating muscle and joint forces.

Main Methods:

• Gait analysis was performed on 30 athletes with acute, unilateral ACL rupture.
• Electromyography (EMG) data from 14 lower extremity muscles were collected bilaterally.
• Musculoskeletal modeling was employed to estimate muscle and joint contact forces.

Main Results:

• Gait mechanics were consistent with previous findings in ACL-deficient individuals.
• A significant finding was altered joint loading in the injured limb, with decreased knee contact forces compared to the uninjured limb.
• Both medial and lateral compartment forces were reduced, without altering the tibiofemoral load distribution.

Conclusions:

• This study is the first to estimate medial and lateral compartment contact forces in acute ACL rupture patients using an EMG-driven model.
• The observed early decrease in injured limb loading warrants further investigation regarding its role in osteoarthritis development.
• Understanding altered joint mechanics post-ACL injury is crucial for long-term joint health management.