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How to relieve knee pain and swelling: what our clinicians do
For a sore, swollen knee, the usual first steps are relative rest, ice, compression, elevation and, if they are safe for you, over-the-counter pain relievers. When fluid keeps building up or arthritis pain does not settle, a physician can drain the extra fluid with a needle (knee aspiration), often watching on ultrasound, and may then inject a corticosteroid to calm the inflammation. Strengthening exercise and physical therapy then help the knee stay strong. The four videos below show this procedure in our offices.
Our short videos of knee aspirations are the most-watched clips on our YouTube channel. Viewers ask the same few questions in the comments: what is that fluid, does it hurt, and will it fix my knee? This article walks through what the videos show, what the procedure can and cannot do, and what you can try first at home.
What you are seeing in these videos
Each clip follows the same basic steps, done in the office with the patient lying down:
- Numbing. The skin is cleaned and numbed. In one video the clinician tells the patient the numbing "should be the worst part."
- Finding the fluid. On the ultrasound screen, fluid shows up as black. The needle tip is guided into that black pocket so the fluid can be drawn out.
- Draining. As fluid is removed, you can watch the pocket shrink ("see that pocket closing?"). Fluid is often clear yellow, but a little blood in it "can certainly happen," as one clinician explains.
- Medication. With the needle still in place, a corticosteroid (steroid) is injected into the joint to calm inflammation.
The whole procedure takes a few minutes. Patients in the videos describe pressure and a pinch, and most are up and walking right after.
Why does fluid build up in the knee?
A swollen knee, sometimes called "water on the knee" or a knee effusion, means extra fluid has collected inside the joint. Common reasons include:
- Osteoarthritis, the wear-related arthritis described in several of these videos
- Injury, such as a meniscus tear or a ligament sprain (see knee pain and injuries)
- Overuse or irritation of the joint lining
- Gout or other inflammatory arthritis
- Infection, which is uncommon but urgent
Removing fluid relieves pressure, and the fluid can be sent to a lab if the cause is unclear. Our swollen knee (knee effusion) guide covers the causes in more detail, and our knee aspiration page explains the procedure step by step.
What aspiration and a cortisone shot can and cannot do
Draining a tense, swollen knee can ease pressure and pain quickly, and the steroid can calm inflammation for a period of time. How long relief lasts varies from person to person. Neither step reverses arthritis or repairs a torn meniscus, and fluid can come back if the cause is still there. Doctors also limit how often steroid is injected into the same joint.
That is why we treat an injection as one part of a plan. Calmer pain makes it easier to do the strengthening work that protects the knee over the long term.
What you can try at home first
For a knee that is sore and puffy but not hot, red or badly injured, these widely recommended steps are a reasonable start:
- Ease off the activity that flares it, but keep the knee gently moving
- Ice for short periods and elevate the leg above heart level
- Use a compression sleeve or wrap for support
- Use over-the-counter pain relievers only if they are safe for you
- Once the pain settles, strengthen the thigh and hip muscles, ideally with physical therapy. If you have had surgery, follow our knee surgery recovery tips
When to see a doctor
Get checked soon if the swelling keeps coming back or does not improve within a few days, or if the knee locks, catches or gives way. Also see a doctor if you cannot put weight on the leg, or if the swelling followed a fall, twist or "pop." Seek care the same day if the knee is hot and red or you have a fever, because infection must be ruled out.
How we treat knee pain at Precision Care
A physician starts with an exam and, when it helps, diagnostic ultrasound in the office. Depending on the cause, the plan may include joint injections, aspiration of fluid or genicular nerve block and radiofrequency ablation for long-standing arthritic knee pain. Physical therapy builds strength and balance. Learn more on our knee pain page.
Related care at Precision Care
Where to get knee pain and swelling checked near you
Knee pain is evaluated by a physician at all three Precision Care offices, and injections, ultrasound and physical therapy are planned by one team. You can request an appointment online or call the office closest to you. An online request is not a confirmed booking until the office contacts you.
A sports medicine doctor can examine a swollen knee, and drain it when that is the right step, at our Brooklyn office serving patients from Sheepshead Bay, Midwood, Brighton Beach and Bensonhurst, our Staten Island office serving patients from New Dorp, Grant City and Great Kills, or our Midtown Manhattan office in Midtown East. Call ahead to confirm which office is best for an aspiration, and request an appointment if you have been searching for “knee pain treatment near me”.
150 E 55th St, Suite 401, New York, NY 10022
(212) 840-0135
Questions patients ask
What is the fluid drained from a swollen knee?
It is extra joint fluid that has built up inside the knee, often because of osteoarthritis, an injury or inflammation. It is usually clear or yellow and can sometimes contain a little blood. If the cause is unclear, the fluid can be sent to a lab for testing.
Does knee aspiration hurt?
The skin is numbed first, and most patients describe a pinch and some pressure rather than sharp pain. In our videos, patients are up and walking right after the procedure.
Why is a cortisone shot given after the fluid is removed?
The corticosteroid calms inflammation inside the joint, which can ease pain and may slow the fluid from building up again. How long relief lasts varies from person to person, and doctors limit how often steroid is injected into the same joint.
Will draining my knee fix my arthritis?
No. Aspiration and a steroid injection can relieve pressure and pain, but they do not reverse arthritis or repair a torn meniscus. They work best as part of a plan that includes strengthening exercise and physical therapy.
When should I see a doctor for a swollen knee?
See a doctor if swelling keeps returning or does not improve within a few days, if the knee locks or gives way, if you cannot bear weight, or after an injury. Seek same-day care if the knee is hot and red or you have a fever.
Can a swollen knee be drained in the office?
Yes. Knee aspiration is an office procedure, usually done after numbing the skin, and often with ultrasound guidance. The physician decides whether draining the fluid fits after examining the knee.
Is there knee aspiration near me in Staten Island?
Our Staten Island office at 1630 Richmond Rd, Suite 101, serving patients from Grant City and Great Kills, evaluates knee pain and offers joint injections, as do our Brooklyn and Midtown Manhattan offices. Call (718) 339-7100 ahead to confirm which office is best for a knee aspiration.
Educational only, not medical advice. These videos and this article explain common treatments in general terms. They are not a diagnosis or a treatment plan for you. Results vary from person to person. See a qualified clinician about your own symptoms, and call 911 or go to an emergency room for an emergency.
More videos and articles on the Precision Care blog