Multiligament Knee Injuries

The knee joint is supported by four primary ligaments: the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL), and lateral collateral ligament (LCL). Each plays a specific role in maintaining stability and coordinated movement. When two or more of these structures are injured simultaneously, the result is a multiligament knee injury. These can vary in severity, from partial sprains to complete ligament tears, and often involve damage to surrounding tissues such as the joint capsule, meniscus, or neurovascular structures behind the knee.

Because of the combined instability, individuals with multiligament injuries typically cannot bear weight or perform normal activities. Such injuries are often accompanied by knee dislocation, which temporarily disrupts joint alignment and can endanger nearby nerves and blood vessels.

The symptoms of a multiligament knee injury typically appear immediately after trauma and are more severe than those of a single-ligament tear. Common signs include:

• Significant swelling and bruising within hours of the injury
• Severe pain that worsens with movement or pressure
• A feeling that the knee has “given out” or cannot support weight
• Visible deformity or abnormal alignment of the leg
• Restricted range of motion or inability to fully straighten or bend the knee
• Numbness, tingling, or coldness in the foot, which may indicate vascular or nerve involvement

Because the knee’s blood vessels and nerves are located close to the joint, any loss of sensation or color in the lower leg is considered a medical emergency and requires immediate evaluation.

Multiligament knee injuries typically occur during events that place excessive force or abnormal rotation on the knee joint. Common causes include:

• Motor vehicle collisions – High-speed impacts or dashboard injuries that push the tibia backward can rupture the PCL and other stabilizing ligaments.
• Sports accidents – Contact sports such as football, soccer, and skiing are common sources of hyperextension, twisting, or side impacts that cause complex ligament damage.
• Falls or trauma – Landing awkwardly from a jump or sustaining a blow to the side of the knee can create forces strong enough to tear multiple ligaments.
• Workplace or industrial accidents – Sudden slips, crush injuries, or heavy equipment trauma may lead to extensive ligamentous disruption.

Certain factors can increase the risk or severity of these injuries. Athletes who participate in high-impact or pivoting sports are more vulnerable. Previous ligament injuries or existing knee instability can also predispose an individual to further damage. In addition, patients with weak quadriceps or poor neuromuscular control may experience greater instability and delayed recovery following trauma.

Accurate diagnosis of a multiligament knee injury requires a detailed physical examination and advanced imaging studies. During evaluation, Dr. Collon will inquire about your symptoms and how your injury occurred. He will assess joint stability, range of motion, and neurovascular function. Special tests help identify which ligaments are affected.

Imaging plays a critical role in confirming the diagnosis and planning treatment.

• Magnetic resonance imaging (MRI) is the gold standard for visualizing soft tissue structures and determining the extent of ligament tears.
• X-rays may be used to assess bone alignment, identify fractures, or detect knee dislocations.
• In severe trauma cases, CT angiography may be ordered to ensure that the major arteries and veins behind the knee are intact, as vascular injury is a serious potential complication.

Prompt diagnosis is essential not only to restore stability but also to prevent long-term complications such as chronic instability, cartilage damage, and early-onset arthritis. When blood vessel injury is suspected, surgical intervention may be required within hours to preserve limb function.

If untreated or inadequately managed, multiligament injuries can lead to chronic pain, stiffness, and progressive joint degeneration. The loss of ligament stability increases stress on cartilage surfaces, accelerating wear and contributing to osteoarthritis. Persistent instability can also cause repeated episodes of knee buckling, making physical activity and daily movement difficult. In cases involving vascular or nerve injury, complications can extend to impaired circulation or muscle weakness in the lower leg. For athletes and active individuals, recovery may require a prolonged rehabilitation process to regain full function and confidence in the joint.