Medial and Lateral Collateral Ligament Injuries

What Causes Collateral Ligament Injuries?

Before you start, it will be very helpful to review knee anatomy, specifically, where the medial and lateral collateral ligaments are located, and how the knee works. You can always refer to this information later in the article.

Ligaments are not meant to be very elastic. They typically function to stabilize bones to one another. The collateral ligaments of the knee stabilize the knee by limiting side-to-side movement of the tibia and femur in relation to one another. There are two collateral ligaments of the knee — the medial (MCL or inner) and lateral (LCL or outer) collateral ligaments.

The collateral ligaments are commonly injured structures in the knee. Injuries happen in many ways. Injury to a collateral ligaments usually result from a forceful injury to the knee, such as a fall while skateboarding or skiing or a hard direct hit to the side of the leg or knee. Ligaments can be stretched, partially torn, or fully torn. Injuries to ligaments are typically referred to as sprains. 

If the force against the knee or leg is great enough, other ligaments can tear as well. A common ligamentous injury pattern of the knee is a combined tear of the medial collateral ligament (MCL) and a tear of the anterior cruciate ligament (ACL).

Symptoms of Collateral Ligament Injuries

Sudden tearing of a ligament may cause pain, swelling or difficulty in walking. Oftentimes, ligamentous injuries are associated with damage to the soft tissue structures in and around the knee. This can result in bleeding within the joint (or hemarthrosis). Initially, the knee can become stiff and painful. However, as the initial stiffness and pain go away, your knee joint may begin to feel unstable.

How Collateral Ligament Injuries are Diagnosed

The diagnosis of a torn collateral ligament will begin with your doctor asking you questions about your initial injury and the symptoms that you have been experiencing. Your doctor will perform an examination of your knee to give him/her clues regarding your injury. Ligamentous injuries are oftentimes easily diagnosed off of your physical exam. X-rays typically do not show ligamentous injuries and are mainly useful in making sure that there are no associated bony injuries. Depending on your symptoms, your doctor may order a MRI scan to get a better look at the soft tissue structures around the knee, including the collateral ligaments.

Treatment of Collateral Ligament Injuries

Most injuries to the collateral ligaments will heal on their own with simple brace support, physical therapy, and time. An isolated injury to the lateral collateral ligament or medial collateral ligament usually does not require surgical repair or reconstruction.

The initial treatment for a collateral ligament injury focuses on reducing the inflammation (pain and swelling) in the knee. This can be accomplished with rest, initial icing, and anti-inflammatory medications (such as ibuprofen, alleve).  Bracing helps to support the ligaments to promote healing. As the ligaments are allowed to heal, a physical therapy program will further help to reduce pain and inflammation, improve motion, and regain strength.

Here are some examples of what your therapy may consist of:

Range of motion: Range-of-motion exercises help you to get back the normal movement of joints and muscles if your knee has become stiff. Early on, these exercises must be done slowly and carefully to avoid further irritation or injury to the ligaments. You will likely be taught how to do exercises at home so that these exercises can be performed daily.

Early strengthening exercises: The goal of early strengthening exercises is to help you get back your muscle strength, prevent muscle atrophy (or wasting away), and to reduce pain. These strengthening exercises may include:

  • Resistance training – as your symptoms improve, you can begin a progression of resistance exercises to restore strength and control to the muscles in your hip and knee.
  • Closed kinetic chain exercises – these exercises are done with the foot planted on the ground. This allows the muscles around the knee to be exercised while easing stress on the ligaments. These exercises are “functional” because they represent ordinary activities that we do throughout the day. Examples include stepping, squatting, lunging, and half kneeling.
  • Balance/proprioception exercises – these exercises are very important after a ligament injury. Proprioception is the awareness of posture, movement and balance in relation to the body. Healthy ligaments inform the brain regarding the position of the joint. This is how we subconsciously know that our limbs are safely positioned at all times — even with our eyes closed. Therefore, when a ligament has been injured, these receptors may be unable to receive and send this information to the brain — which may increase the chances of sustaining another injury. Balance and proprioception exercises help to restore our sense of position by heightening the sensitivity of the uninjured receptors. These exercises include standing or walking on uneven or very soft surfaces, balancing on one leg, balancing on a mini-trampoline, and progressive agility drills.

Ultimately, during the rehabilitation period, you will continue to progress to more intensive exercises as your knee pain and strength improves.  High-level exercises like agility drills, running and cutting, combination strength and speed exercises for power (plyometrics), and heavy resistance training can be done to prepare your knee for return to a specific high demand job or sport.

Surgery for a Collateral Ligament Injury

If there are injuries in addition to the collateral ligament or you have persistent symptoms, surgery may be warranted. Usually ligaments are reconstructed or reinforced, rather than repaired (i.e. put directly back together).

Which reconstructive option will be best for you depends on the type of injury you have sustained. Additionally, there are numerous ways to reconstruct each ligament.

Finally, ligament injuries can be associated with other ligamentous, meniscal or cartilage injuries.  These are oftentimes concomitantly addressed at the time of surgery if the surgeon thinks that it is necessary.

Its important to remember that ligaments take a long time to heal. You may have to limit the amount of weight you put on your knee or your motion around the knee for several weeks after a ligament reconstruction. You’ll likely need crutches to get around initially and your surgeon may ask that you wear a brace to help support your knee while it heals. At some point, strength and range-of-motion exercises will be needed to get your muscles strong enough to support your knee. It can sometimes take up to a year to get back to your normal activities.

Note that the information in this article is purely informative and should never be used in place of the advice of your treating physicians.

Dr. Andrew Chung
Dr. Andrew Chung

Dr. Andrew Chung is a Spine Surgeon at Sonoran Spine in Tempe, Arizona. He is a graduate of the Philadelphia College of Osteopathic Medicine and was formerly Spine Surgeon Clinical Fellow at Cedars-Sinai, Spine Surgery Fellow at Keck Hospital, University of Southern California and Chief Resident and an Instructor of Orthopedic Surgery in the Department of Orthopedic Surgery at the Mayo Clinic in Arizona. Dr. Chung's research.