Knee Swelling

  • The Cleveland Clinic states that knee swelling is typical and is often a symptom of an underlying injury or chronic medical condition. A swollen knee can have many potential causes.
  • According to the Mayo Clinic, there are three significant symptoms of knee swelling. These include knee effusion, a buildup of joint fluid in the knee, limited mobility, and pain. 
  • There are ways to treat a swollen knee at home, including resting, icing and compression, and taking over-the-counter medications like ibuprofen. A sports medicine doctor may treat knee swelling. In severe cases, knee swelling knee surgeon. 

Health Report Live features well-researched articles that give seniors the information they need to address swollen knees and other conditions. 

These are the essential facts about knee swelling, treating the cause of a swollen knee, and when to see your doctor.  

What is Knee Swelling?

According to the Cleveland Clinic, knee swelling is a common symptom of many possible causes. These knee swelling causes can come from damage and disease related to the muscles, bones, tendons, ligaments, and nerves inside the knee.

Knee swelling can be moderate to severe. It’s important to note that knee swelling can also be acute and temporary and part of a chronic condition. Severe knee swelling can even limit your mobility and cause noticeable joint pain. 

What Does It Mean If Your Knee Is Swollen?

Knee swelling is a general symptom associated with various potential causes. These causes can range from simple bumps and injuries that will resolve themselves in a few days to more complicated conditions that will need medical treatment.

Here’s a partial list of a few major causes of knee swelling. According to the Cleveland Clinic, many of these conditions are known causes of knee pain

  • Runner’s knee
  • Osgood-Schlatter disease
  • Tendonitis
  • Types of arthritis 
  • Anterior cruciate ligament (ACL) injuries or a meniscus tear
  • Burtis 
  • Patella (knee cap) dislocation 
  • Many more possible conditions 

Symptoms of Knee Swelling

The Mayo Clinic lets us know that there are three significant symptoms of knee swelling. The most noticeable of these is an increase of fluid in the knee which can cause the need to enlarge, especially when compared to a normal knee.

This increase in fluid, also known as effusion, can limit the mobility of the knee, either making it difficult to straighten or bend. Depending on the cause of the knee swelling, you might also experience pain or an inability to put weight on the swollen knee. 

When to See a Doctor

Many causes of knee swelling are pretty minor and can resolve themselves with over-the-counter medications and at-home treatment in a few days. However, if your knee swelling increases, turns red, or becomes too warm to the touch, you should schedule an appointment with your doctor.

You should see a doctor for knee swelling if the pain increases or if there are any new symptoms such as burning sensations, bleeding, or a loss of sensation in or around the knee. 

Potential Causes of Knee Swelling

There are many potential causes of knee swelling. The professionals at the Mayo Clinic inform us that knee swelling may be caused by physical injuries and chronic medical conditions and can be exacerbated by risk factors such as personal health and age.

We will take a look at a few of the more common causes of knee swelling that you can address with your doctor. 


Physical injuries are a common cause of knee swelling. Damage to the knee often causes excessive fluid buildup as the body attempts to heal this injury. These injuries can result from sports injuries, overuse, or accidental damage.

Johns Hopkins states that a common cause for this type of injury is a torn ligament or a tear in the meniscus. Ligaments are soft tissue that helps add support to the structure of the knee, while the meniscus is the cushions that protect the knee joint as it moves and bears weight.

Broken bones can also cause knee swelling. This swelling may also come from minor damage to bones, such as the runner’s knee and the grinding stemming from the worn-down meniscus.


Effusions are caused by a buildup of fluids in the joints. The Cleveland Clinic states that these effusions may be caused by infections, injuries, or chronic medical conditions. Effusions last as long as the underlying condition that causes them lasts. 

Diseases and Conditions

Knee swelling is a general symptom, which means various medical conditions can cause it. Your doctor will have to do tests to determine which conditions are causing your particular knee swelling.

Let’s take a closer look at a few of the most common causes of knee swelling.


Arthritis is a major cause of knee swelling. There are several different types of arthritis.

The most common type of arthritis is knee osteoarthritis. Knee osteoarthritis occurs as the knee joint’s cartilage breaks down with age and overuse.

Arthritis means swelling and inflammation of the joint. The majority of people in the United States have arthritis. The causes of arthritis range from diet and lifestyle to autoimmune conditions and age.

Reactive Arthritis (Reiter’s Syndrome)

A swollen knee can be caused by reactive arthritis, including Reiter’s syndrome. Reactive arthritis is caused by an infection in one area of the body, triggering a bout of arthritis in the knees or legs. Infections of the intestines or genitals most often trigger reactive arthritis.

Reactive arthritis affects men and women equally. However, men are more likely to experience reactive arthritis after a genital infection. This is why safe sex practices are essential in order to avoid reactive arthritis.

Reactive arthritis typically clears up on its own within 12 months. However, you should see your doctor if you experience arthritis after an infection of the intestines or genitals.

Septic Arthritis

Septic arthritis is caused when an infection reaches the synovial fluid inside the joints or the joint tissues. These infections typically reach the joint through the bloodstream; however, they can also reach the joint through a serious injury.

Septic arthritis is often caused by viruses, strep, staph infections, or gram-negative bacteria. Individuals with compromised immune systems as well as children are at higher risk for septic arthritis.

Juvenile Rheumatoid Arthritis

Juvenile rheumatoid arthritis tends to affect children 16 years of age and younger. Unlike rheumatoid arthritis in adults, children tend to outgrow this condition, although it could affect their bone growth. 

Juvenile rheumatoid arthritis is an autoimmune condition which means the body’s own immune system attacks its healthy cells.

Rheumatoid Arthritis

Rheumatoid arthritis, like juvenile rheumatoid arthritis, is an autoimmune condition. The specific causes of this autoimmune condition are not known. Rheumatoid arthritis is often associated with risk factors like heart disease, image, smoking, and alcohol consumption.

Knee Osteoarthritis

Knee osteoarthritis is the most common type of arthritis found in the knee and is caused by the wear and tear of the knee joint. Individuals over the age of 50 are at the highest risk for this type of arthritis.


Gout and pseudogout are other common types of arthritis. Unlike different kinds of knee arthritis, gout is more strongly linked to diet and can be treated by making lifestyle changes. According to Johns Hopkins, gout was known as the “disease of kings” because of its association with diets full of rich foods and alcohol.


Pseudogout is a sudden onset type of gout. This condition can last for several days or up to several weeks. It’s caused by crystalline deposits in the joint and affects the knee more than any other joint in the body.

Half of the adult population over the age of 85 suffers from pseudogout.

Baker’s Cyst

A baker’s cyst is a fluid-filled cyst that forms in the joint behind the knee. These cysts are often caused by conditions like arthritis or damage to the knee joint. A baker’s cyst can make it painful or difficult to flex the joint of the knee.


Tumors can also cause knee swelling. A common type of tumor found in the knee is known as osteosarcoma. This is a common type of bone cancer that causes healthy bone cells to grow erratically. 

These are weaker than normal bone cells and can contribute to knee swelling.

Osgood-Schlatter Disease

Osgood-Schlatter disease is caused by too much tension being applied to the patellar tendon, where it attaches to the top of the shin bone. This condition is common in children as the patellar tendon attaches near the growth plate of the tibia, which is more sensitive in children.

Bursitis (Non-septic or Septic)

Knee swelling can also be caused by knee Bursitis, which can also cause septic arthritis. This is an inflammation of a fluid-filled sac in the knee. 

This can be caused by not adequately stretching before exercising, problems with physical fitness, or overuse of the knee that leads to injury.

Different Risk Factors and Complications

There are lifestyle factors that can create an increased likelihood of having a swollen me. One of the most significant risk factors is age because the condition of the cartilage inside the knee tends to degrade as we age. 

Other risk factors include diet, sports, and physical fitness, as well as medical conditions which can increase the likelihood of gout or arthritis. 

The swelling itself also causes complications. It’s important to note that even though the swelling is a symptom rather than a disease in its own right, it can still cause medical complications.

The Mayo Clinic states that effusion can cause muscle loss and muscle atrophy complications. The fluid can also build up and create painful Baker’s Cysts inside the knee. 

Potential Treatments Knee Swelling

Treating a swollen knee can take one of two different approaches. The swelling itself can be treated, which is called symptomatic treatment. This prevents the swelling from causing complications and can also treat some underlying conditions.

There can also be a treatment for the conditions that are causing the swelling. Knee swelling treatments can range from surgeries to repair a damaged ligament to medications for arthritis and other chronic medical diseases. 


The Mayo Clinic states that there are a variety of medicines that can be prescribed for a swollen knee. These can include pain relievers to treat the physical discomfort of a swollen knee. These medications may also include antibiotics to treat infections and medicines designed to relieve arthritis. 

Surgical and Other Procedures

Some causes of knee swelling need to be treated with surgery. A torn ligament is one of the more common physical causes of severe knee swelling. These are commonly prepared using surgery. 

Arthrocentesis is a surgical treatment that removes fluid from the knee. 

This directly reduces swelling. Doctors may also inject corticosteroids after this procedure to treat inflammation. Your doctor may also recommend a knee replacement in severe circumstances. 

Researchers at Johns Hopkins pointed out that total knee replacement should be considered a last resort. This is because individuals who receive a total knee replacement will likely require a second total knee replacement after some time. Total knee replacements are expected to last around 20 years. 

Different Lifestyle and Home Remedies To Take Note

Treatment for a swollen knee often starts at home. Knee swelling is so common that individuals usually begin their treatments using lifestyle changes and over-the-counter remedies. If these treatments don’t reduce the knee swelling in a few days, you should visit your doctor for more detailed medical advice. 


Both John Hopkins and the Mayo Clinic recommend resting to help treat a swollen knee. This is because swollen knees can be caused by injuries, overuse, and other conditions that benefit from some rest.

Even swollen knees caused by chronic medical conditions can benefit by relieving the strain and stress that comes from use. Taking a quick rest is a great way to treat swollen knees. 


Researchers writing for Pain Research and Management conducted a randomized control trial and found that treating swollen knees with ice packs successfully relieved this condition. Ice reduces inflammation and pain while freeing up some mobility in the knee. 


The same group of researchers also found that compression was successful in treating swollen knees. Gently compression can be achieved at home or by using an over-the-counter knee brace. This helps to reduce swelling. 


Elevating your knee is part of a class of treatment known as RICE. This stands for Rest Ice Compress and Elevate. The Elevation helps to reduce the swelling by allowing gravity to help drain fluid from the knee. 

The Journal of Athletic Training stated that individuals should use RICE on a case-to-case basis.  

Take Anti-Inflammatory Medications

Anti-inflammatory medications help reduce the swelling. These can be excellent choices for acute knee swelling caused by minor injuries. Anti-inflammatory medications might not work if your knee swelling is caused by a chronic medical condition.

Pain-relieving medications, like nonsteroidal anti-inflammatory (NSAIDs) medication, can help manage pain and reduce swelling. Acetaminophen also reduces pain in the affected knee.

Switch to Heat

Switching between a cold and hot compress is a classic approach to sports injuries. Alternating between cold and hot helps the fluids in the knee to circulate, which reduces inflammation and swelling. 

Try Massage

Gentle massages are a great way to help move fluids out of a swollen area. However, caution should be taken as massages can also aggravate underline conditions and physical injuries. If massage is causing you physical discomfort or pain, it should be discontinued.

Do Knee Exercises

The Cleveland Clinic reminds us that knee exercises also have a place in overcoming swollen knees and other injuries. 

Physical rehabilitation exercises can help individuals overcome injuries and chronic conditions that cause knee swelling. These exercises can improve your range of motion, reducing the risk of knee injuries or sprains.

Ways To Prevent Knee Swelling

There are a few things that you can do to prevent knee swelling before it happens. One of the most important things to do is make lifestyle changes that reduce knee overuse, improve your diet to avoid arthritis and gout, and get regular physical exercise that boosts the strength of your knee.

Visiting your doctor early on is also a great way to prevent knee swelling. It is typically easier to treat underlying conditions when they are first detected rather than trying to treat them when they become more complicated. 

Getting a Diagnosis

It is essential to visit your doctor if you’ve been experiencing knee swelling that doesn’t seem to go away on its own or with that home treatment. Knee swelling is a symptom, and this means that you could be telling you that there’s an underlying medical condition that needs treatment.

One of the first things that your doctor will do is make a physical examination of the knee. This includes testing the flexing of the knee joint, looking for physical injuries, and asking you questions about your knee and your health. After the physical inspection, your doctor will move on to some Imaging tests. 

Imaging Tests

Imaging tests help doctors to look inside the knee without needing to use invasive surgeries or other techniques. Standard imaging tests for a swollen knee include x-rays, ultrasounds, and an MRI. These will give you a doctor’s a better look at what’s going on inside your knees so that they can come up with a diagnosis. 

Joint Aspiration (Arthrocentesis)

Joint aspiration is a procedure that removes excess fluid from a joint. It’s common for joint aspiration to be done on swollen knees that have not responded to at-home treatment. Even if this will not fix the underlying medical conditions, it will provide temporary relief for a swollen knee. 

When Should I Worry About A Swollen Knee?

Swelling around the knee is not always cause for concern. However, there are a few signs that your knee swelling needs to be addressed by a medical professional.

If your knee swelling has not responded to at-home treatment or over-the-counter medication, it’s time to schedule an appointment with your doctor. Knee swelling that does not seem to be going away on its own is also a sign that you need medical treatment.

If your knee swelling is accompanied by severe pain, you could also see a doctor. Not being able to put weight on the knee is also a sign that it needs medical treatment.

Signs of an infection are also a cause for alarm when it comes to a swollen knee. This includes the knee feeling hot to the touch, the swollen knee being red, or any signs of pus or discoloration. 

Why Would A Knee Swell Without Injury?

There are a variety of reasons why your knee would start swelling without an apparent injury. Knee swelling can be caused by conditions that don’t have a surface wound or a noticeable physical impact.

These causes of knee swelling without injury include infections, arthritis, gout, and other chronic diseases. Knee swelling can also be caused by tumors and cysts that grow in or near the knee. 

What To Prepare For Your Appointment

Preparing for your appointment helps your doctor come up with a diagnosis quickly. You can get ready for your swollen knee doctor’s appointment by following these steps.

  • Write down details about your symptoms, such as anything that triggers a flare-up or recent injuries 
  • Make a list of any medications that you take. Include vitamins and supplements as well. 
  • Make a list of any autoimmune conditions that are in your family 
  • Make a list of your known medical conditions 
  • Have a few questions ready to ask your doctor 
  • Be prepared to take notes during your appointment 

What You Can and Must Do for a Knee Swelling Doctor’s Appointment 

The first thing you should do is to follow the list above to prepare for the appointment, which will make things faster for both yourself and your doctor.

It would help if you also considered coming to the appointment with a trusted friend or family member. This is especially the case if your knee swelling is severe and it’s challenging to move around.

It is essential to be honest with your doctor about the nature of your swollen knee. This includes your level of discomfort and pain, as well as the types of physical activities that aggravate your swollen knee. 

Questions to Ask Your Doctor

It is essential to know what to ask your doctor when you visit for a swollen knee. These are just a few basic questions. However, you should ask questions that are more specific to your personal medical history.

  • What at-home treatments can I do for my swollen knee?
  • Are there over-the-counter medications that can improve my condition?
  • What lifestyle changes can I make to improve my swollen knee?
  • Are there any simple physical therapy exercises I can do at home? 

What to Expect From Your Doctor

Your doctor will ask questions about your swollen knee as well as your medical history. These questions are designed to give the doctor a better picture of your current condition so that they can make a diagnosis. Here are a few common questions that doctors ask about a swollen knee.

  • Have you had any recent knee injuries?
  • Do you play sports, work out, or have fitness routines?
  • Does your family have a history of arthritis?
  • Do you feel you can reliably put weight on your knee?  

Health Report Live has the best information for seniors looking to take better care of their joints and physical health. Check out our other articles related to knee swelling, knee pain, and common causes like arthritis and other conditions. 

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Sean Byers, MD

Sean Byers, MD

Sean Byers is currently a Resident in the Internal Medicine program at UTMB. He studied at the University of Queensland School of Medicine as well as received his Master’s in Public Health with a focus in epidemiology and biostatistics at the University of Southern California. His background is in biology, computer science, public health, and internal medicine.

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