Swollen Knee

Your knee can swell when extra fluid builds up inside or around the joint. Doctors sometimes call this a knee effusion.

Swollen knees can happen because of things like a fall, overuse, or a medical problem. To figure out why your knee is swollen, your doctor might need to take a small sample of the fluid to check for things like infection, disease, or blood from an injury.

Taking some of the fluid out can help reduce the pain and stiffness the swelling causes. Once the cause is found, treatment can start.

Your knee might feel swollen, stiff, and painful. These are common signs of excess fluid in your knee joint.

• Swelling: Noticeably, the skin around your kneecap might look puffy and larger than the skin on your other knee. This swelling is a key indicator of extra fluid.

• Stiffness: If there's extra fluid in your knee, it can make it hard to move your leg freely. You may not be able to fully bend or straighten your knee. This stiffness is often a result of the extra fluid pressing on the joint.

• Pain: The pain in your knee can vary greatly, depending on what's causing the fluid buildup. Sometimes, the pain is mild and manageable. In other cases, the pain is severe enough to make it difficult, or even impossible, to put any weight on your knee.

If home treatments like ice and rest don't help your knee pain, see a doctor. If one knee is noticeably redder and warmer than the other, get medical help right away. This could be a sign of a joint infection.

Knee swelling can be caused by a variety of issues. This includes injuries like sprains or fractures, as well as illnesses and other medical problems.

Several things can make your knee swell up. One factor is age. As you get older, your risk of knee swelling, often due to arthritis, goes up. Arthritis is a condition where the cartilage in your joints wears down, causing pain and swelling.

Another factor is playing sports. If you play sports that involve twisting your knee, like basketball or soccer, you're more likely to injure your knee in a way that leads to swelling. This can happen from a sudden twist, a hard landing, or other impacts.

Finally, being overweight or obese also increases your chances of a swollen knee. Extra weight puts extra pressure on your knee joints. Over time, this extra pressure can damage the tissues around the joint and lead to arthritis, which can cause swelling and pain.

A swollen knee can sometimes lead to problems. Here are a few things that might happen:

• Weakened muscles. Extra fluid in the knee can interfere with how your muscles work. This can cause the muscles in your thigh to get weaker and shrink over time.

• A Baker's cyst. The extra fluid can also build up and form a cyst, like a fluid-filled sac, in the back of your knee. This is sometimes called a Baker's cyst. A Baker's cyst can be painful, but often gets better with simple treatments like ice and compression. If the swelling is very bad, a doctor might need to drain the fluid with a needle.

A swollen knee often happens because of an injury or a long-term health problem. Taking care of your body can help prevent swollen knees and other problems. Here are some things you can do:

• Build stronger muscles around your knee. Strong muscles act like support beams for your knee joint, reducing the pressure on it. This is important, especially if you have activities that put a lot of stress on your knees. Exercises like squats, lunges, and hamstring curls can help strengthen these muscles.

• Do activities that are easy on your knees. Some exercises put a lot of pressure on your knee joints. Activities like water aerobics and swimming are gentler on your knees because they don't involve the same amount of weight-bearing pressure. Walking is another good option, but make sure you use proper form to avoid putting too much strain on your knees.

• Keep a healthy weight. Carrying extra weight puts extra stress on your joints, including your knees. This can lead to more wear and tear over time, potentially causing or worsening knee swelling. Maintaining a healthy weight through a balanced diet and regular exercise is key to protecting your knees.

Your doctor will likely start by asking about your health history and giving you a physical exam of your knee. They'll then probably order some tests to figure out what's causing the swelling.

To pinpoint the problem, imaging tests can be very helpful. These tests create pictures of the inside of your knee:

• X-rays: X-rays are good at showing if there are any broken or dislocated bones. They can also help determine if you have arthritis. An X-ray takes a picture of the hard parts of your body, like bones.

• Ultrasound: This test uses sound waves to create a picture of the soft tissues in your knee, like tendons and ligaments. It's useful for checking if there's a problem with these tissues. Imagine a doctor using a special tool to "see" inside your knee without surgery.

• MRI (Magnetic Resonance Imaging): An MRI uses a powerful magnet and radio waves to create detailed images of your knee. This is especially helpful for seeing soft tissues like tendons, ligaments, and cartilage. An MRI can show problems that X-rays might miss.

Sometimes, your doctor might need to take a small sample of fluid from inside your knee. This fluid can be tested to see what's causing the swelling. The lab will look for:

• Blood: Blood in the fluid could mean you have an injury or a problem with your blood clotting.

• Bacteria: Bacteria in the fluid could indicate an infection.

• Crystals: Certain crystals can build up in your knee joint, causing conditions like gout or pseudogout. These crystals are often the cause of sudden, severe pain and swelling.

These tests help your doctor diagnose the problem and create a treatment plan for your swollen knee.

Knee swelling treatment depends on why your knee is swollen, how bad it is, and your overall health.

To improve your knee's strength and movement, physical therapy exercises are often helpful. A knee brace might also provide support in some cases.

If there's an underlying reason for the swelling, several treatments are available:

• Removing fluid (Arthrocentesis): Sometimes, your knee joint fills with extra fluid, putting pressure on the joint. A doctor can drain this fluid, relieving the pressure. After draining the fluid, they might also inject a medicine called a corticosteroid into the knee to reduce inflammation. This is like giving anti-inflammatory medicine directly to the joint.

• Looking inside the knee (Arthroscopy): A small, lighted tube (arthroscope) is inserted into your knee through a small cut. Attached to the arthroscope are special tools. These tools can be used to remove pieces of damaged or loose tissue inside the knee joint. They can also help repair any problems found. This procedure is used when there's damage inside the joint that needs to be addressed.

Caring for a swollen knee involves a few simple steps:

• Rest: Don't put weight on your knee as much as you can. This means avoiding activities that put pressure on your knee joint, like running or jumping. If you need to move around, use crutches or a walker to take the pressure off your knee. Simple activities like walking short distances, or standing for short periods may be okay depending on the severity of the swelling. Listen to your body and avoid any activity that causes significant pain.

• Ice and Elevation: Applying ice to your knee helps reduce pain and swelling. Use a cold pack, ice bag, or even a bag of frozen peas. Hold the ice on your knee for 15 to 20 minutes every 2 to 4 hours. Crucially, keep your knee elevated above your heart. This helps to drain the fluid away from the knee. You can use pillows to prop your leg up comfortably.

• Compression: Wrapping your knee with a stretchy bandage can help reduce swelling. This compression helps keep the injured area stable and prevents further fluid buildup. Make sure the bandage is snug, but not too tight that it cuts off circulation. If you're not sure how to wrap your knee properly, ask a doctor or pharmacist for help.

• Pain Relief: Over-the-counter pain relievers, like acetaminophen (often called Tylenol) or ibuprofen (like Advil or Motrin), can help ease the pain. Follow the directions on the package carefully. If the pain is severe, or if you have any concerns about taking over-the-counter medicine, it's important to talk to your doctor.