About Combined Knee Ligament Injuries

Combined knee ligament injuries refer to damage to more than one of the four main ligaments in the knee joint at the same time. This type of complex injury is often caused by trauma, such as a sports injury or high-impact accident.

The four primary ligaments in the knee are:

• Anterior cruciate ligament (ACL) – controls rotation and forward movement of the tibia
• Posterior cruciate ligament (PCL) – controls backward movement of the tibia
• Medial collateral ligament (MCL) – provides stability to the inner knee
• Lateral collateral ligament (LCL) – provides stability to the outer knee

Combined ligament injuries typically involve tears of the ACL and PCL, along with at least one collateral ligament (MCL or LCL). The LCL is often injured in combination with other structures due to the complex anatomy on the outside of the knee.

Common Symptoms

Symptoms of combined ligament injuries include:

• Knee instability and feeling of giving way
• Swelling and intense pain
• Difficulty with certain movements like side-to-side motion
• Possible nerve damage or vascular injury in severe cases

Cause & Anatomy

Combined knee ligament injuries are typically caused by severe trauma or impact to the knee joint, such as:

• Direct contact to the knee, like in football, hockey, or other contact sports
• Sudden twisting of the knee, especially when the feet stay planted one way but the knees turn the other way, as can happen in sports like skiing, basketball, and football
• Sudden direct impact to the knee, such as in a car accident or football tackle
• Falls from a height or other major trauma

The knee joint relies on ligaments and surrounding muscles for stability, making it vulnerable to injury from these types of forces.

While the medial collateral ligament (MCL) is the most commonly injured ligament in isolation, MCL injuries are sometimes associated with tears of the anterior cruciate ligament (ACL) or other ligaments. Lateral collateral ligament (LCL) tears are often accompanied by injuries to other structures in the knee due to the complex anatomy on the outside of the joint.

In severe cases, multiple ligament injuries can also disrupt blood supply to the leg or affect the nerves that supply the limb’s muscles. This can lead to serious complications like amputation if major blood vessels or nerves are damaged.

Diagnosis

Diagnosing combined knee ligament injuries may involve the following:

Clinical Examination

• A detailed patient history about the cause of injury and any previous knee problems is essential.
• A thorough physical examination is crucial to assess the extent of ligament damage.
• The Lachman test is reliable for detecting anterior cruciate ligament (ACL) injuries, but its accuracy may be affected by muscle guarding or certain tear patterns.
• The pivot shift test is best performed under anesthesia for reproducible results.

Imaging

• MRI is highly accurate for diagnosing acute ACL injuries and can detect partial tears, chondral lesions, and posterior joint injuries.
• MRI is the most effective imaging test to confirm the diagnosis and guide surgical planning for complex multi-ligament injuries.

Arthroscopy

• Diagnostic arthroscopy can be combined with open surgery to directly visualize the extent of ligament and cartilage damage.
• Arthroscopy allows the surgeon to make a precise diagnosis and formulate the optimal treatment plan.

Vascular Assessment

• Careful evaluation of the extremity’s vascular status is essential, as multi-ligament injuries can disrupt blood supply to the leg.
• Vascular surgeons may need to be consulted if there are concerns about arterial or venous injuries.