Knee Ligament Sprains and Tears, Causes and Symptoms

Knee ligament sprains and tears occur when the ligaments in the knee joint get overstretched or torn. The knee is one of the most complex joints in the body because it connects the thighbone and shinbone and is used for so many essential functions, such as walking and jumping. When the knee functions correctly, it uses the ligaments and bone to help bend the knee, which is essential for movement. When one or more of these ligaments get torn or sprained, movement can become difficult, if not impossible. These strains and tears are some of the most common sports injuries.

While these injuries can occur in people of any age, the majority of people who incur these knee ligament sprains and tears are athletes between the ages of 25 and 45. This is because athletes put more strain on their joints while playing sports and working out. While these are debilitating injuries, they are treatable and most people are able to return to regular activity after treatment.

Anatomy of the Knee
The knee is the joint where the thighbone and shinbone meet. It consists of the following:

  • The patella (the kneecap)
  • The femur (the thighbone)
  • The tibia (the shinbone)
  • Collateral ligaments (those around the sides of the kneecap)
  • Cruciate ligaments (those inside the knee joint)

The knee is one of the most complex joints because it brings together two large bones and provides mobility for important daily functions. The ligaments in the knee are there to help stabilize the body.

Types of Knee Ligament Sprains and Tears
Knee ligament sprains and tears can occur to any of the 4 main ligaments:

Anterior Cruciate Ligament (ACL) – This is the most common ligament to tear and one of the worst, as it provides the most stability in the knee. These injuries affect approximately 95,000 people each year, and are more common in women than men.
Posterior Cruciate Ligament (PCL) – This ligament is usually only torn under powerful force. A sprain or tear usually happens when a person falls on their knee, or they are involved in a car accident where the knee hits the dashboard.
Medial Collateral Ligament (MCL) – This is the most commonly injured collateral ligament. It is located inside the knee, but a blow from the outside of the knee can cause this ligament to strain or tear if the person is standing firmly in place.
Lateral Collateral Ligament (LCL) – This is the collateral ligament on the outside of the knee. It is rarely injured and when it does get strained or torn, it can usually be easily fixed by wearing a brace.  
Multiple Knee Ligament Sprains and Tears – It is possible to have multiple strains or tears in these ligaments. When this occurs, it is important to see a doctor, as there may be more complications that require surgery to fix.

Causes of Knee Ligament Sprains and Tears
There are many causes of knee ligament sprains and tears. Most causes are associated with physical activity or significant force:

  • Twisted knee – If a person’s foot is firmly planted on the ground and they twist it suddenly, or are impacted, forcing the knee to twist abnormally, a sprain, tear or multiple tears can happen.
  • Getting hit on the knee – An impact to the knee can cause the ligaments to tear as they are forced out of their natural position at a sudden high velocity.
  • Hyperextension – When a person’s knee is stretched too far, the ligaments may not be able to keep up and will sprain or tear as a result of the hyperextension.
  • Landing incorrectly – When a person jumps, they put significant force on their knee as they land. When this is done incorrectly, the ligaments can tear.
  • Stopping suddenly while running – This is another sudden movement that can cause the ligaments to be forced into a position that is not natural.

Symptoms of Knee Ligament Sprains and Tears
Depending on the knee ligament sprain or tear, symptoms may vary. With each sprain or tear, pain is usually associated with the injury, as well as swelling and tenderness.  

The following are common knee ligament sprain and tear symptoms. Keep in mind that each person reacts differently to trauma:

  • Sudden snap or popping noise
  • Pain in the knee
  • Swelling
  • A feeling that the knee is loose
  • Immobilized knee
  • Inability to put weight on the leg

Knee ligament sprain and tear symptoms may be mistaken for the symptoms of other medical conditions.  Make sure you consult a doctor in order to determine if you have a knee ligament sprain or tear and get the appropriate treatment.  

The multidisciplinary team of orthopaedic experts at North Shore-LIJ Orthopaedic Institute in New York treats Knee Ligament Sprains and Tears as well as a broad range of conditions that affect the bones within the body.

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