Knee Sprain Diagnosis and Treatment

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A knee sprain means that you have injured one of the ligaments around the knee joint. There are four major ligaments that contribute to the stability of the knee. In addition, there are many smaller ligaments that can cause pain after an injury. Sprains and strains are often confused. A sprain is an injury to a ligament, and a strain is an injury to a muscle. 

Ligaments are structures that connect two bones. Ligaments are important in allowing joint stability, while at the same time allowing the joint to move. In the case of the knee, the ligaments allow the knee joint to bend back and forth but control excessive movements.

The collateral ligaments of the knee prevent excessive side-to-side motion, while the cruciate ligaments are important in both rotational and forward/backward stability.

Woman putting ice on sprained knee
PhotoAlto / Odilon Dimier / Getty Images

Knee Sprain Symptoms

The most common symptoms of a knee sprain are pain and swelling. Typically after people who have injured their knee causing damage to the ligaments, they will have immediate symptoms. Sometimes these symptoms worsen over the first 48 hours, and then gradually dissipate, depending on the severity of the injury.

The most common symptoms of a knee sprain include:

  • Knee pain
  • Swelling of the knee
  • Stiffness of the joint
  • Instability/giving-out/buckling


Knee sprains can be caused by a variety of injuries. Sometimes the injuries occur as a result of athletic activities. In athletics, knee sprains can occur both as a result of contact injuries as well as noncontact events.

Knee sprains often occur after falls and other trauma that can occur at home or at the workplace. Knee sprains are also common after automobile accidents.

Similar injuries can lead to other common knee joint problems including fractures and dislocations. For that reason, it is important for people with symptoms of a knee sprain to be evaluated by a medical professional to determine if further testing is necessary.


Evaluation of someone who has injured their knee involves testing the different ligaments that may be injured as a result of a knee sprain. There are specific maneuvers in tests they can isolate each of these ligaments to help your healthcare provider determine the exact cause of your discomfort.

Often specialized tests such as X-rays and magnetic resonance imaging (MRI) will be performed if there is a concern of a more serious injury or if the diagnosis is unclear.

Saying someone has a "knee sprain" is not a terribly useful diagnosis for two reasons:

  • It does not tell you which ligament is injured. This is important because different ligaments are treated very differently. For example, anterior cruciate ligament (ACL) injuries often need surgical reconstruction. On the other hand, medial collateral ligament (MCL) injuries seldom require surgery.
  • It does not tell you how badly the ligament is injured. The reason this is important is that minor injuries usually require minor treatment. More severe injuries may require more substantial treatment, rehabilitation, and possibly surgery.

Despite this, patients are often told they have a knee sprain. If you are diagnosed with a knee sprain, try to get more information. Find out which ligaments are injured, and then you will be able to understand more about what possible treatments and rehabilitation are necessary. 


Often knee ligament injuries are graded to define the severity of the injury. A grade of injury is meant to give an indication of the extent of damage to the ligament. In general, most healthcare providers grade on a scale of 1 to 3.


The grades of a ligament tear are:

  • Grade I: A minor injury that will likely recover with rest and activity modifications over the course of 1-2 weeks
  • Grade II: A moderate injury with partial tearing of the ligament that will require more limitations in activities and may take 4-6 weeks for recovery
  • Grade III: A complete or near-complete tear of the ligament. Depending on the ligament damaged, this may require either more prolonged rehabilitation or surgical intervention.

These general classifications are somewhat arbitrary, and the truth is a ligament can be damaged in many ways across a spectrum from no injury to a complete tear. Therefore, these categories are used most notably to give athletes a sense of the severity of the injury and a timeline for an expected return to their athletic endeavors.

As stated, the primary problem with calling an injury a knee sprain is that these words do little to convey much useful information. Knowing the specific ligament injured will help your healthcare provider and you team up to find the best treatment to ensure you return to your normal activities as soon as possible.

A Word From Verywell

Spraining your knee means that you have damaged one or more of the ligaments that surround the joint. These ligaments are critical to the stability of the knee joint and when injured may require specialized treatment.

When a knee sprain is suspected, a careful examination and specialized tests can be performed to determine the extent of the injury and the optimal treatment.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Evans J, Nielson J l. Anterior cruciate ligament (ACL) knee injuries. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2019.

  2. Knee ligament sprains and tears: Clinical practice guidelines—ensuring best care. J Orthop Sports Phys Ther. 2017;47(11):824. doi:10.2519/jospt.2017.0511

  3. Makhmalbaf H, Shahpari O. Medial collateral ligament injury; A new classification based on MRI and clinical findings. A guide for patient selection and early surgical intervention. Arch Bone Jt Surg. 2018;6(1):3-7.

Additional Reading

By Jonathan Cluett, MD
Dr. Cluett is board-certified in orthopedic surgery. He served as assistant team physician to Chivas USA (Major League Soccer) and the U.S. national soccer teams.