Anatomy and Function of the Knee
Before you start, it will be very helpful to read our information to better understand knee anatomy, 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.
What Causes Collateral Ligament Injuries?
The collateral ligaments are commonly injured structures in the knee. Injuries happen in many ways. Injury to a collateral ligament usually involves a significant force to the knee, such as a fall while skateboarding, skiing or a hard direct hit to the side of the leg or knee.
Ligaments connect or attach bones to bones. The collateral ligaments stabilize the knee by limiting side-to-side movement of the tibia and femur. Ligaments are not meant to be very elastic. If the collateral ligaments are forced to stretch too far, they can tear. The medial collateral ligament can tear in the middle of the ligament, where the medial collateral ligament attaches to the tibia, or where the medial collateral ligament attaches to the femur.
If the force against the knee or leg is great enough other ligaments can tear as well. The most common ligament injury combination is a tear of the medial collateral ligament and a tear of the anterior cruciate ligament.
The lateral collateral ligament on the side of the knee opposite where the force hit can also be torn, but it is less common than a medial collateral tear. The lateral collateral ligament can be torn in areas similar to tears of the medial collateral ligament.
Symptoms of Collateral Ligament Injuries
A force strong enough to cause a knee injury that actually tears one of the collateral ligaments also causes significant damage to the soft tissues in the knee. There is bleeding into the tissues, swelling of the tissues and sometimes bleeding into the knee joint itself, called effusion. The knee becomes stiff and painful. As the initial stiffness and pain goes away your knee joint will feel unstable, and may give away and not support your body weight.
How Collateral Ligament Injuries are Diagnosed
The history (your story of what happened to cause the injury) and physical examination usually gives a very good idea of what ligaments have been torn in and around the knee.
X-rays may be taken to rule out the possibility that bone damage has also happened. Stress x-rays can be helpful to confirm that one of the collateral ligaments has been torn. Stress x-rays plain x-rays taken with someone attempting to open the side of the knee that might have the torn ligament. If instability is present, x-rays will show a widening of the joint space on the torn side.
An MRI scan may be ordered if there is evidence that multiple injuries have occurred, including injury to the meniscus or anterior cruciate ligament.
Treatment of Collateral Ligament Injuries
Most injuries to the collateral ligaments will heal with immobilizing the knee joint in a cast or brace for 4-6 weeks. 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. Rest and anti-inflammatory medications, such as aspirin or NSAIDs, can help reduce the pain and swelling. As the ligament heals, a physical therapy program will further help reduce pain and inflammation, improve motion, and regain strength.
Controlling Pain and inflammation: Your physical therapist has a wide assortment of ways to help control pain and inflammation including electrical stimulation, cold packs or wraps, and ultrasound.
Rest: Rest is beneficial in the early stages of healing to give your knee a chance to recover. Your brace may be locked in place at first to avoid painful movements in your knee. Don’t "overdo it" during the early stages of recovery. You’ll must remove the brace several times during the day and do careful range-of-motion exercises followed by applying ice packs.
Range of motion: Range-of-motion exercises help you to get back the normal movement of joints and muscles. While you’re sore, these exercises must be done slowly and carefully to avoid further irritation or injury. You will likely be taught how to do exercises at home to increase the motion in your knee. As your soreness goes away, more vigorous stretching can be used to get back the full, normal movement in your knee.
Early strengthening exercises: The goal of early strengthening exercises is to help you get back your muscle strength, prevent wasting of the muscles, and reduce pain.
Isometric exercises: Isometrics are strengthening exercises where the muscles are working but the joint doesn’t move. Isometrics allow you to exercise safely with the knee at different angles, helping you stay away from painful positions of the knee. The benefit of Isometrics is to reduce overall pain and swelling in the knee.
Early resistance exercises: As your symptoms get better, 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 to 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 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 awareness of posture, movement and balance in relation to the body. Healthy ligaments tell the brain the position of the joint. This is how we know right where our limbs are positioned—even with our eyes closed. Once a ligament has been injured, these receptors are unable to receive and send this information to the brain increasing the chances of another. Balance and proprioception exercises help to restore our sense of position by heightening the sensitivity in 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.
Program progression: You can do more intensive exercises as the pain and irritation in your knee are controlled. 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 a specific job or sport.
Surgery for a Collateral Ligament Injury
If there are injuries in addition to the collateral ligament, surgery may be needed. Some orthopedic surgeons feel that a combination tear of the anterior crucial ligament and medial collateral ligament should be treated with surgery. Other surgeons do not, and feel that the medial collateral ligament tear should be treated with casting and arthroscopy done later to reconstruct the anterior crucial ligament.
The meniscus is not likely to be injured in combination with an injury to the collateral ligaments.