Multi-Ligament Knee Injury

The knee is the most complex joint in your body and uses a delicately balanced system of bones, ligaments, and other structures to allow you to run, jump, perform cutting movements, and other advanced activities. The knee is made up of three bones: the femur (thigh bone), the tibia (shin bone), and the patella (kneecap). The two joints of the knee are the tibiofemoral joint (between the femur and tibia bones, this is the main knee joint) and the patellofemoral joint (between the kneecap and the trochlea, a groove on the front of the femur). The fibula bone is a thin bone on the outside of your lower leg that does not contribute to the knee joint, but is important to ankle stability. 

Due to the geometry of the knee joint, it is inherently unstable and relies on ligaments, tendons, and other soft tissue (non-bony) structures for stability. 

• Ligaments: The knee ligaments support the knee through range of motion

  • Anterior cruciate ligament: This ligament is the most commonly discussed ligament, as it is commonly injured. It is located in the middle of the knee and runs from the back of the femur to the tibia. The ACL prevents the tibia from moving too far forward.

  • Posterior cruciate ligament: This ligament is also located in the middle of the knee and runs from the front of the femur to the back of the tibia. The PCL prevents the tibia from sliding too far backward.

  • Medial collateral ligament: This ligament is located along the inside of the knee and runs from a bony prominence on the inside of the femur to the inside of the tibia. It prevents the knee from collapsing inward.

  • Lateral collateral ligament: This ligament is located along the outside of the knee and runs from a bony prominence on the outside of the femur to the top of the fibula bone. This ligament works in concert with other soft tissue structures to prevent the knee from collapsing outward.

Multi-ligament knee injuries occur as a result of a major traumatic event to the knee, such as a motor vehicle collision, fall from height, or high-speed sports injury. These injuries involve damage to multiple ligaments in the knee and often have associated bony and other soft tissue injuries.

Symptoms & Diagnosis

Patients with multi-ligament knee injuries will note knee instability with activity and occasionally with low-impact activities, such as walking. Initially, patients will experience significant knee swelling and will have difficulty with knee range of motion and ambulation. Multi-ligament knee injuries are diagnosed using physical examination and imaging studies to confirm the diagnosis. The physical examination is used to identify areas of pain, changes in range of motion, and knee instability. X-rays help evaluate for the presence of any associated bony injuries. MRI (magnetic resonance imaging) is an important part of the diagnosis and will allow evaluation of all the knee ligaments, meniscus, cartilage, and any other structures that may have been injured.

Treatment

Multi-ligament knee injuries can be treated with non-surgical or surgical means. Specific injuries with minimal ligament damage can be amenable to non-surgical treatment. Non-surgical options can include:

• Rest and activity modification: All sports and active pursuits should be stopped until the knee swelling resolves. Occasionally, patients require several weeks of crutch use to regain a normal gait.

• Non-steroidal anti-inflammatory medications (NSAIDs) and use of ice can help decrease inflammation.

• Brace: Use of a knee brace can help the patient feel more confident and secure when walking

• Physical therapy: This is an important tool to help you strengthen and retrain the muscles of the knee to work better together

Patients with significant injury to the ligaments of the knee or those with a persistent feeling of instability of the knee benefit from surgical treatment. Surgery is best if performed within 1-2 weeks after the injury to reduce scar tissue formation and improve post-operative function. The complexity of multi-ligament knee injuries means that each patient has an individualized plan of care based on the structures that are injured. Surgical intervention involves reconstruction of injured ligaments with either autograft (from the patient) or allograft (from a deceased donor) tissue and repair of associated injuries to the meniscus, cartilage, bone, etc.

Multi-ligament knee injuries can be severe injuries and require prolonged rehabilitation with slow progression of physical therapy. Patients can anticipate a return to activities at 12 months after surgery.