Acute knee pain is sudden and may be caused by damage, swelling, or irritation of the muscles and tissues that support the knee. Pain may result from:

  • A fall.

  • An injury to the knee from twisting motions.

  • A hit to the knee.

  • Infection.

Acute knee pain may go away on its own with time and rest. If it does not, your health care provider may order tests to find the cause of the pain. These may include:

  • Imaging tests, such as an X-ray, MRI, CT scan, or ultrasound.

  • Joint aspiration. In this test, fluid is removed from the knee and evaluated.

  • Arthroscopy. In this test, a lighted tube is inserted into the knee and an image is projected onto a TV screen.

  • Biopsy. In this test, a sample of tissue is removed from the body and studied under a microscope.

Follow these instructions at home:

If you have a knee sleeve or brace:

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  • Wear the knee sleeve or brace as told by your health care provider. Remove it only as told by your health care provider.

  • Loosen it if your toes tingle, become numb, or turn cold and blue.

  • Keep it clean.

  • If the knee sleeve or brace is not waterproof:

    • Do not let it get wet.

    • Cover it with a watertight covering when you take a bath or shower.

Activity

  • Rest your knee.

  • Do not do things that cause pain or make pain worse.

  • Avoid high-impact activities or exercises, such as running, jumping rope, or doing jumping jacks.

  • Work with a physical therapist to make a safe exercise program, as recommended by your health care provider. Do exercises as told by your physical therapist.

Managing pain, stiffness, and swelling

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  • If directed, put ice on the affected knee. To do this:

    • If you have a removable knee sleeve or brace, remove it as told by your health care provider.

    • Put ice in a plastic bag.

    • Place a towel between your skin and the bag.

    • Leave the ice on for 20 minutes, 2–3 times a day.

    • Remove the ice if your skin turns bright red. This is very important. If you cannot feel pain, heat, or cold, you have a greater risk of damage to the area.

  • If directed, use an elastic bandage to put pressure (compression) on your injured knee. This may control swelling, give support, and help with discomfort.

  • Raise (elevate) your knee above the level of your heart while you are sitting or lying down.

  • Sleep with a pillow under your knee.

General instructions

  • Take over-the-counter and prescription medicines only as told by your health care provider.

  • Do not use any products that contain nicotine or tobacco, such as cigarettes, e-cigarettes, and chewing tobacco. If you need help quitting, ask your health care provider.

  • If you are overweight, work with your health care provider and a dietitian to set a weight-loss goal that is healthy and reasonable for you. Extra weight can put pressure on your knee.

  • Pay attention to any changes in your symptoms.

  • Keep all follow-up visits. This is important.

Contact a health care provider if:

  • Your knee pain continues, changes, or gets worse.

  • You have a fever along with knee pain.

  • Your knee feels warm to the touch or is red.

  • Your knee buckles or locks up.

Get help right away if:

  • Your knee swells, and the swelling becomes worse.

  • You cannot move your knee.

  • You have severe pain in your knee that cannot be managed with pain medicine.

Summary

  • Acute knee pain can be caused by a fall, an injury, an infection, or damage, swelling, or irritation of the tissues that support your knee.

  • Your health care provider may perform tests to find out the cause of the pain.

  • Pay attention to any changes in your symptoms. Relieve your pain with rest, medicines, light activity, and the use of ice.

  • Get help right away if your knee swells, you cannot move your knee, or you have severe pain that cannot be managed with medicine.

This information is not intended to replace advice given to you by your health care provider. Make sure you discuss any questions you have with your health care provider.