Acute Knee Ligament Injuries

Ligament Tears and Forces

• A valgus force applied to the knee is most likely to cause a medial collateral ligament (MCL) tear.
• A valgus force with rotation applied to the knee is most likely to cause an ACL (anterior cruciate ligament) tear.
• A valgus force, rotation, and weight bearing applied to the knee is most likely to cause an ACL and MCL tear.
• A varus force applied to the knee is most likely to cause a lateral collateral ligament (LCL) tear.
• A varus force with rotation applied to the knee is most likely to cause an LCL and posterior cruciate ligament (PCL) tear.

Diagnostic Tests and Imaging

• The anterior drawer test is used to diagnose ACL tears.
• The Lachman test is used to diagnose ACL tears.
• The posterior sag sign indicates a posterior cruciate ligament (PCL) tear.
• The Lachman test is used to assess for anteroposterior glide in the knee.
• MRI is used to differentiate partial from complete tears.

Treatment and Management

• The initial treatment for a partial tear is conservative management.
• The initial treatment for a complete MCL or LCL tear is surgical reconstruction.
• The initial treatment for a complete ACL or PCL tear is surgical reconstruction.
• The initial treatment for a combined collateral ligament tear and ACL or PCL tear is surgical reconstruction.
• Avulsion injuries should be surgically treated if they are displaced or involve a large fragment of bone.
• Arthroscopy is used to assess the extent of an ACL tear and perform surgical reconstruction.

Examination Techniques

• The posterior sag sign test is performed with the hip and knee in 90 degrees of flexion.

Test your knowledge on acute knee ligament injuries and their mechanisms of injury with this quiz. Learn about the various ligaments involved and how they contribute to knee stability. Perfect for athletes, healthcare professionals, and anyone interested in understanding common knee injuries.