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Multi-Ligamentous Knee Instability

What is Multi-Ligamentous Knee Instability?

Knee ligaments are short bands of tough, flexible connective tissue that connect bones together and give the joint stability and strength. There are four main ligaments in the knee, which connect the thigh bone (femur) to the shin bone (tibia):

The cruciate ligaments are found inside your knee joint, and cross each other to create an X. They control the back and forth motion of your knee as well as rotational or pivoting motions.

  • Anterior cruciate ligament (ACL). The ACL is in the center of your knee, and is primarily responsible for controlling the back and forth and rotational motion of your knee.
  • Posterior cruciate ligament (PCL). The PCL is behind the ACL. The primary function of the PCL is to control the backward motion of your shin bone.

The collateral ligaments are found on the sides of your knee. The medial collateral ligament (MCL) stabilizes the inner part of the knee, while the lateral collateral ligament (LCL) stabilizes the outer part of the knee. They control the sideways motion of your knee, and prevent it from sliding too far to one side.

  • Medial collateral ligament (MCL). This ligament gives stability to the inner knee.
  • Lateral collateral ligament (LCL). This ligament gives stability to the outer knee.

There are smaller, more intricate, ligaments that are associated with each the MCL and LCL that help form complexes.  Dr. Patel will discuss those ligaments with you after evaluation. 

A knee ligament injury can involve any of the four main ligaments. Most knee ligament injuries involve a single ligament injury, with a tear to the ACL being the most common. When several  ligaments are torn at the same time, it is known as a multi-ligamentous knee injury (MLKI).

Knee ligament injuries most often happen while participating in sports that involve sudden turns, pivoting, or cutting maneuvers. Multi-ligamentous knee injury is a rare but serious injury usually occurs when there is a direct blow to the knee (such as a football tackle or a motor vehicle collision), hard muscle contraction (changing direction rapidly while running) or a fall from a height.

While a knee can be dislocated without tears of both cruciate ligaments, a combined anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) injury can be associated with a knee dislocation (KD). Schenck’s classification of KDs is based on the number of ruptured ligaments.

  • KD I. Injury to a single cruciate ligament (ACL or PCL)
  • KD II. Injury to both cruciate ligaments (ACL and PCL)
  • KD III. Injury to both cruciate ligaments (ACL and PCL) and either collateral ligaments (MCL or LCL)
  • KD IV. Injury to both cruciate ligaments (ACL and PCL) and both collateral ligaments (MCL or LCL)
  • KD V. Knee fracture

These are very traumatic injuries and can unfortunately be associated with injury to the nerves or arteries of the leg as well.

When ligaments are damaged, the knee joint may become unstable (buckle or give way). Range of motion in the knee joint is limited, so the patient may not be able to pivot, turn, or twist the leg.

Other symptoms include:

  • Severe pain
  • Swelling
  • Instability of the knee joint
  • Inability to walk
  • Lack of control of the limb
  • Damage to nerves or arteries in the leg

Swelling can make it difficult to diagnose a knee injury, so it is important to seek medical attention right away after a traumatic injury to the knee. In addition to a very a thorough physical exam and X-rays (including stress x-rays), an MRI (magnetic resonance image) will confirm a diagnosis of injury to multiple knee ligaments.

While treatment for single ligament tears may be conservative, most patients with a diagnosis of MLKI require the surgical reconstruction of ligaments (using grafts or tendon tissue from the patient or human donors) and extensive post-operative rehabilitation. If there is artery or nerve damage this can require emergent attention and intervention. These injuries may often be staged or done in a single procedure depending on all of the associated injuries.

Surgery for combined ligament tears is often performed carefully after the injury, as multi-ligamentous knee injuries can have serious complications, such as disrupting blood supply to the leg or affecting the nerves that supply the muscles of the limb.

Dr. Patel is the leading expert in Multi-ligamentous knee injuries in the Chicagoland area. He performs more multi-ligamentous knee surgeries than any other surgeon given his affiliation with multiple Level 1 trauma hospitals in the area. Other Orthopaedic surgeons in the midwestern states frequently consult Dr. Ronak Patel for his expertise in this area and transfer patients to his care.

In the past, a combined ligament injury could end your sports career. Today, it is possible to return to professional sports after a multi-ligamentous knee injury. However, it is important to note that surgical outcomes for multi-ligamentous knee injuries are not as consistent as they are for single ligament surgery. Dr. Patel will spend time with you and your family going over the specific injury pattern, the recovery timeline and prognosis.

Anatomic treatment provides the best results, allowing for greater function and mobility, a return to an active lifestyle, and less risk of developing arthritis in the future.

At a Glance

Ronak M. Patel M.D.

  • Double Board-Certified, Fellowship-Trained Orthopaedic Surgeon
  • Past Team Physician to the Cavaliers (NBA), Browns (NFL) and Guardians (MLB)
  • Published over 49 publications and 10 book chapters
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