What is a knee sprain?

The knee is comprised of a complex assortment of bones, ligaments, cartilage, and muscles. The three major bones of the knee are the femur (thigh bone), tibia (shin bone), and the patella (kneecap). In addition to being supported by the menisci and the joint capsule, the knee is stabilized by ligaments. These ligaments act to prevent movement when the knee is forced beyond its normal range of motion. The main four ligaments of the knee include the anterior cruciate ligament (ACL), the posterior cruciate ligament (PCL) and the medial and lateral collateral ligaments (MCL and LCL). A sprain is classified as a stretching and subsequent tearing to any one of these ligaments.

What causes a knee sprain?

Knee ligaments may be injured during athletic or occupational activities involving sudden force. Knee sprains may be caused by:

  • Forced twisting of the knee
  • Stopping suddenly while running
  • Shifting your weight while running or skiing
  • Landing awkwardly after jumping
  • A blow to the outer or inner side of the knee
  • A blow to the front of the knee while the knee is bent and the foot is firmly planted on the ground

What are the symptoms of a knee sprain?

Symptoms of a knee sprain depend on the location and severity of the knee ligaments damaged. Some symptoms may include the following:

  • Pain and swelling
  • Tenderness and occasionally bruising
  • Difficulty walking

How is a knee sprain diagnosed?

A discussion of your symptoms, a physical examination, and X-rays are useful for a diagnosis. Your specialist may recommend having an MRI as well.

How is a sprain treated?

Depending on the severity of your sprain, your physician may prescribe exercise, physical therapy, anti-inflammatory medications, and/or cortisone injections. Supportive braces may need to be worn to allow your ligaments to heal. In cases that don’t respond to other care, surgery may be required.

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