Knee Sprain

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What is a knee sprain?

A sprain is an injury to a ligament that develops due to overstretching. A ligament is a band of tough tissue that holds bones together and supports joint motion. Four ligaments are important in maintaining the stability and function of the knee joint, the anterior and posterior cruciate ligaments and the medial and lateral collateral ligaments. Knee and ankle sprains are among the most common types of sprains that occur in the body.

A knee sprain typically occurs as a result of trauma, and sports injuries are one of the most common causes of knee sprain. The ligament may tear, either partially or completely, when it is excessively stretched. Symptoms may vary in severity and include pain and swelling along with an inability or decreased ability to move the knee joint. Some people report that they hear a popping noise at the time of the injury.

A thorough clinical evaluation will be able to accurately diagnose knee sprain and identify if any other knee injuries are present.

Many cases of knee sprain can be treated at home with rest, ice packs, and over-the-counter pain relief medications. More-serious cases may require treatment with a brace or other device to help you keep the knee immobilized. If a ligament is completely torn, surgery may be needed to repair the knee joint.

A knee sprain is rarely a serious injury that would require emergency care. However, it may be associated with more-serious injuries. Seek immediate medical care (call 911) for serious symptoms, such as paralysis, loss of sensation, absent pulses in the feet, the inability to move the knee joint, severe bleeding, or uncontrollable pain.

Seek prompt medical care if you have any pain, soreness, or other problems with your knee, or if you are being treated for a knee injury and symptoms recur or are persistent.


What are the symptoms of a knee sprain?

Symptoms of knee sprain begin following the injury and may be mild or severe.

Common symptoms of a knee sprain

The symptoms of knee sprain can vary in their intensity. You may hear a popping noise at the time of the injury to your knee. Common symptoms of knee sprain include:

  • Bruising
  • Inability to bear weight on the affected leg
  • Inability to move the knee joint, or restricted mobility of the joint
  • Instability of the joint
  • Pain (may be described as dull, sharp, burning, stabbing or aching)
  • Swelling
  • Warmth and redness of the skin

Symptoms that might indicate a serious condition

In some cases, a knee sprain may accompany other serious injuries. Seek immediate medical care (call 911) if you, or someone you are with, have any of these serious symptoms including:

  • Coldness of the feet, with weak or absent pulses
  • High fever (higher than 101 degrees Fahrenheit)
  • Loss of sensation in the lower leg
  • Obvious breakage or deformity of the bones
  • Paralysis
  • Severe bleeding
  • Uncontrollable pain


What causes a knee sprain?

Knee sprain is caused by an injury to the knee joint that results in one or more of the ligaments of the joint being stretched excessively. Sports and activities that may involve stress or twisting of the knee joint, including downhill skiing, football, and basketball, may increase your risk of sustaining a knee sprain. A knee sprain can also result from a blow to the knee or from a fall in which you land on your knees.

What are the risk factors for a knee sprain?

A number of factors increase the risk of knee sprain. Not all people with risk factors will get knee sprain. Risk factors for knee injury include:

  • Occupational activities that expose the knee to risk of injury (slips, falls)
  • Participation in certain sports, particularly that involve stress or twisting of the knee joint such as downhill skiing
  • Previous knee injury

Reducing your risk of a knee sprain

You may be able to lower your risk of knee sprain by wearing proper and well-fitting footwear for sports activities.


How is a knee sprain treated?

Many cases of knee sprain can be treated at home with rest, ice packs, and over-the-counter pain relief medications. More-serious cases may require treatment with a brace or other device to help you keep the knee immobilized. In some cases, a combination of these methods will be used by your treatment team. Knee sprains are treatable, and it is important to exactly follow the treatment plan that your health care team has designed specifically for your injury.

Treatments for a knee sprain

Treatment options for knee sprain include:

  • Braces, splints or compression bandages to aid in immobilization of the joint after injury
  • Ice packs after the acute injury to reduce swelling
  • Medications for pain relief such as acetaminophen (Tylenol) and ibuprofen (Advil)
  • Physical therapy to strengthen the knee joint and surrounding muscles
  • Rest and elevation of the affected knee after the acute injury
  • Surgery to repair torn ligaments

What are the potential complications of a knee sprain?

You can help minimize your risk of serious complications by following the treatment plan you and your health care professional design specifically for you. Complications of knee sprain include:

  • Absenteeism from work or school
  • Decreased athletic performance
  • Disability
  • Joint deformity and destruction
  • Permanent or chronic pain
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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2018 Dec 30
  1. Knee problems.
  2. Knee problems. National Institute of Arthritis and Musculoskeletal and Skin Diseases.
  3. Kahan S, Miller R, Smith EG (Eds.). In A Page Signs & Symptoms, 2d ed. Philadelphia: Lippincott, Williams & Williams, 2009
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