The anterior cruciate ligament. A functional analysis based on postmortem studies

Area of Science:

• Orthopedic Surgery
• Biomechanics
• Human Anatomy

Background:

• The anterior cruciate ligament (ACL) is crucial for knee stability.
• The ACL has distinct functional components: the anteromedial band and the posterolateral part.
• Understanding the specific roles of these components is vital for diagnosing and treating knee injuries.

Purpose of the Study:

• To investigate the functional contribution of the anterior cruciate ligament (ACL) and its two main parts (anteromedial band and posterolateral part) to knee stability.
• To determine the role of the ACL in limiting anterior translation, rotation, and hyperextension of the knee joint.

Main Methods:

• The study involved forty fresh human cadaver knees.
• Ligaments, including the ACL and medial collateral ligament, were sectioned in various combinations.
• Manual stress tests, including the anterior drawer test, were performed to assess knee laxity and rotational stability.

Main Results:

• The anteromedial band of the ACL is essential for preventing the anterior drawer sign; its severance is required to elicit this sign.
• The posterolateral part of the ACL and the medial collateral ligament act as secondary and tertiary restraints, respectively, against anterior translation.
• The entire ACL significantly restrains both internal and external rotation, particularly in knee extension, and also limits hyperextension.

Conclusions:

• The anteromedial band is the primary dynamic stabilizer preventing anterior tibial translation.
• The ACL, as a whole, plays a critical role in controlling rotational knee stability and preventing hyperextension.
• These findings enhance the understanding of ACL function and have implications for surgical reconstruction and rehabilitation strategies.