Stress and strain changes of the anterior cruciate ligament at different knee flexion angles: A three-dimensional finite element study

Objective

This study aimed to analyze the stress and strain changes of the anterior cruciate ligament (ACL) at different knee flexion angles using a three-dimensional finite element model.

Methods

Computed tomography and magnetic resonance imaging scans were performed on the right knee of 30 healthy adult volunteers. The imaging data were used to construct a three-dimensional finite element model of the knee joint. The magnitude and concentration area of stress and strain of ACL at knee flexion angles 0°, 30°, 60° and 90° were assessed.

Results

The magnitude of stress remained consistent at 0–30° (P > 0.999) and decreased at 30–90° (P < 0.001, P = 0.005, respectively), while the magnitude of strain increased between 0° and 30° (P = 0.004) and decreased between 30° and 90° (P < 0.001, P = 0.004, respectively). The stress concentration area remained consistent at the proximal end, midsubstance, and distal end between 0° and 60° (P > 0.05). The concentration area of strain increased at the proximal end, decreased at the midsubstance between 0° and 30°, and remained consistent between 30° and 90° (P < 0.001).

Conclusion

At the low knee flexion angle, ACL's magnitude of stress and strain reached the peak, and the concentration area of ACL strain gradually shifted from midsubstance to the proximal end.