Which knee structure is most likely injured in an anterior cruciate ligament tear during a non-contact pivoting injury?

Which knee structure is most likely injured in an anterior cruciate ligament tear during a non-contact pivoting injury?

• A. Anterior cruciate ligament
• B. Lateral collateral ligament
• C. Medial collateral ligament
• D. Posterior cruciate ligament

Answer: (A)

In a non-contact pivoting injury, the knee is forced through rapid change of direction with the foot planted, causing internal rotation of the tibia and often a valgus collapse. The ACL runs through the center of the knee and is the main restraint against anterior tibial translation and internal rotation. Those twisting and deceleration forces place the greatest tensile load on the ACL, making it the structure most likely to tear in this scenario. The collateral ligaments, while important, are more typically stressed by direct valgus or varus forces or contact injuries, not the twisting pivot seen here. The posterior cruciate ligament is stressed by posterior tibial translation, such as in a dashboard-type injury or hyperflexion. So the mechanism points to tearing of the ACL.

In a non-contact pivoting injury, the knee is forced through rapid change of direction with the foot planted, causing internal rotation of the tibia and often a valgus collapse. The ACL runs through the center of the knee and is the main restraint against anterior tibial translation and internal rotation. Those twisting and deceleration forces place the greatest tensile load on the ACL, making it the structure most likely to tear in this scenario. The collateral ligaments, while important, are more typically stressed by direct valgus or varus forces or contact injuries, not the twisting pivot seen here. The posterior cruciate ligament is stressed by posterior tibial translation, such as in a dashboard-type injury or hyperflexion. So the mechanism points to tearing of the ACL.