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Knee Effusion


Knee effusion is fluid buildup in your knee joint that makes your knee swell and ache. It may be caused by arthritis or by an injury or trauma, such as a knee sprain. Knee effusion may also happen if you exercise too much. It may be painful to bend or straighten your knee, or walk.



  • Rest your knee so it can heal. Limit activities that increase your pain.
  • Ice can help reduce swelling. Wrap ice in a towel and put it on your knee for as long and as often as directed.
  • Compression with a brace or bandage can help reduce swelling. Use a brace or bandage only as directed.
  • Elevation helps decrease pain and swelling. Elevate your knee while you are sitting or lying down. Prop your leg on pillows to keep your knee above the level of your heart.


  • NSAIDs may decrease swelling, pain, or fever. This medicine is available without a doctor's order. Ask your primary healthcare provider (PHP) which medicine to take. Ask how much to take and when to take it. Follow directions. NSAIDs can cause stomach bleeding or kidney problems if not taken correctly. If you take blood thinner medicine, always ask your PHP if NSAIDs are safe for you.
  • Acetaminophen decreases pain and fever. It is available without a doctor's order. Ask how much to take and when to take it. Follow directions. Acetaminophen can cause liver damage if not taken correctly.
  • Prescription pain medicine may be given. Do not wait until the pain is severe before you take your medicine.
  • Take your medicine as directed. Contact your PHP if you think your medicine is not helping or if you have side effects. Tell him if you are allergic to any medicine. Keep a list of the medicines, vitamins, and herbs you take. Include the amounts, and when and why you take them. Bring the list or the pill bottles to follow-up visits. Carry your medicine list with you in case of an emergency.

Use crutches as directed:

You may need crutches to help you walk while your knee heals. Crutches may also help you keep weight off your knee, and prevent more knee damage. Ask your PHP for more information about how to use crutches.

Walking with Crutches

Physical therapy:

A physical therapist can teach you exercises that help improve your movement and decrease knee pain. Physical therapy can also help improve your strength and decrease the risk for loss of function in your knee.

Follow up with your PHP or orthopedic specialist as directed:

Write down your questions so you remember to ask them during your visits.

Contact your PHP or orthopedic specialist if:

  • It gets harder or more painful to straighten your leg at the knee.
  • Your pain worsens.
  • Your knee weakens, or you continue to limp.
  • You have questions or concerns about your condition or care.

Return to the emergency department if:

  • Your knee is warm, red, and tender.
  • You have new swelling 12 to 24 hours after your injury.
  • Your knee locks or gives way. This may cause you to fall.
  • Your feet or toes start to look pale or feel cold.
  • You cannot bear weight on your leg, or you have severe pain even after treatment.

© 2015 Truven Health Analytics Inc. Information is for End User's use only and may not be sold, redistributed or otherwise used for commercial purposes. All illustrations and images included in CareNotes® are the copyrighted property of A.D.A.M., Inc. or Truven Health Analytics.

The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.