Arthritis of the Knee

Overview

What is arthritis of the knee?

Arthritis is a disease that causes pain, swelling and stiffness in your joints. It can affect the largest and strongest joints in your body. It’s common in knees. Arthritis of the knee can be a serious, debilitating disease.

Although there is no cure for knee arthritis, there are steps you can take that might ease your symptoms and potentially slow the progression of your disease.

What is the knee joint?

Three bones come together to form your knee joint. They include the:

  • Thighbone (femur).
  • Shinbone (tibia).
  • Kneecap (patella).

A smooth substance called cartilage covers the ends of each bone. It’s a cushion between the bones that keeps them from rubbing together. The synovial membrane, a type of tissue that surrounds the joint, lubricates the cartilage.

Arthritis of the knee

Arthritis of the knee causes pain and swelling in the joint

What are the types of arthritis of the knee?

There are around 100 types of arthritis. The most common types that might affect your knees include:

  • Osteoarthritis is the most common of the types on this list. Osteoarthritis wears away your cartilage — the cushioning between the three bones of your knee joint. Without that protection, your bones rub against each other. This can cause pain, stiffness and limited movement. It can also lead to the development of bone spurs. Osteoarthritis gets worse as time passes.
  • Post-traumatic arthritis is a type of osteoarthritis. The cartilage starts thinning after trauma to your knee (like an injury from a car crash or contact sport). Your bones rub together, and that causes the same symptoms as osteoarthritis: pain, stiffness and limited movement. Your knee arthritis symptoms might not start until years after the trauma.
  • Rheumatoid arthritis is an autoimmune disease. A healthy immune system causes inflammation (internal or external) when it's trying to protect you from an infection, injury, toxin or another foreign invader. The inflammatory response is one way your body protects itself. If you have rheumatoid arthritis, you have an unhealthy immune system that triggers inflammation in your joints even though there’s no foreign invader. The inflammation causes pain, stiffness and swelling of the synovial membrane, which can also wear away your cartilage.

Who does arthritis of the knee affect?

People of all ages can get arthritis, including arthritis of the knee. If you’re age 50 or older, you have a higher risk of getting knee arthritis. Women get knee arthritis more often than men.

How common is arthritis of the knee?

Over 50 million adults have arthritis, as do 300,000 children. It’s unclear how many of those people have arthritis of the knee.

What are the stages of arthritis of the knee?

There are five stages of osteoarthritis, the most common type of arthritis that affects your knees:

  • Stage 0 (Normal). If you’re at stage 0, your knees are healthy. You don’t have arthritis of the knee.
  • Stage 1 (Minor). Stage 1 means that you’ve got some wear and tear in your knee joint. You probably won’t notice pain.
  • Stage 2 (Mild). The mild stage is when you might start to feel pain and stiffness, but there’s still enough cartilage to keep the bones from actually touching.
  • Stage 3 (Moderate). If you’re at the moderate stage, you’ll have more pain, especially when running, walking, squatting, and kneeling. You’ll likely notice it after long periods of rest (like first thing in the morning). You're probably in a great deal of pain because the cartilage has narrowed even further and there are many bone spurs.
  • Stage 4 (Severe). Severe osteoarthritis means that the cartilage is almost gone. Your knee is stiff, painful and possibly immobile. You might need surgery.

Symptoms and Causes

What causes arthritis of the knee?

Experts have identified some genes that might cause arthritis, including arthritis of the knee. They predict that there are more genes not yet discovered. You could have a gene linked to arthritis without knowing it and a virus or injury could trigger arthritis of the knee.

Though the cause is unknown, some risk factors increase the possibility of arthritis of the knee. Risk factors of osteoarthritis, specifically, include:

  • Age. Osteoarthritis happens to older adults more often than younger adults and children.
  • Bone anomalies. You’re at a higher risk for osteoarthritis if your bones or joints are naturally crooked.
  • Gout. Gout, also a type of inflammatory arthritis, might lead to osteoarthritis.
  • Injuries. Knee injuries can cause arthritis of the knee.
  • Stress. A lot of stress on your knees from jogging, playing sports or working an active job can lead to osteoarthritis of the knee.
  • Weight. Extra weight puts more pressure on your knees.

What are the signs and symptoms of arthritis of the knee?

There are many signs and symptoms of arthritis of the knee:

  • Creaking, clicking, grinding or snapping noises (crepitus).
  • Difficulty walking.
  • Joint pain that changes (gets better or worse) depending on the weather.
  • Joint stiffness.
  • Knee buckling.
  • Knee joint pain that progresses slowly or pain that happens suddenly.
  • Skin redness.
  • Swelling.
  • Your knee locks or sticks when it’s trying to move.
  • Warm skin.

Pain and swelling are the most common symptoms of arthritis of the knee. Some treatments might reduce the severity of your symptoms or even stall the progression. See your healthcare provider if you have symptoms of knee arthritis.

Does arthritis of the knee cause swelling?

One of the symptoms of knee arthritis is swelling. Swelling causes your knee to look larger.

Diagnosis and Tests

How is arthritis of the knee diagnosed?

Your healthcare provider will probably order X-rays of your knees to check for arthritis. The X-rays should reveal:

  • The type of arthritis.
  • Any changes in your bones.
  • Bone spurs.
  • How narrow the space is between the bones. The less cartilage, the narrower the space. The narrower the space, the greater the pain.

Sometimes healthcare providers order a magnetic resonance imaging (MRI) test or a computerized tomography (CT) scan.

What questions might a healthcare provider ask to diagnose arthritis of the knee?

Your healthcare provider will interview you when you report your symptoms. Some questions might include:

  • Does anyone in your family have arthritis of the knee?
  • Does your knee swell up?
  • Is your skin often red?
  • Is your skin often warm?
  • Do you have symptoms in one knee or both?
  • How long have you had these symptoms?
  • What medications do you take?
  • How severe is your pain?
  • Do you struggle to walk?
  • Do the symptoms interfere with your daily activities?

Management and Treatment

Is arthritis of the knee permanent?

Arthritis in your knee will likely always affect you. But some treatments help reduce the severity of the symptoms and maybe keep the disease from getting worse.

How is arthritis of the knee treated?

Healthcare providers can't cure knee arthritis. But they have some tips that might reduce the severity of your symptoms and possibly stop the arthritis from getting worse, including:

  • Maintain a healthy weight.
  • Exercise using low-impact activities (swimming, cycling) instead of high-impact activities (jogging, tennis). Aim for about 150 minutes of exercise per week.
  • Wear shock-absorbing inserts in your shoes.
  • Apply heat or ice to the area.
  • Wear a knee sleeve or brace.
  • Physical therapy exercises that help with flexibility, strength and motion.
  • Use a cane.
  • Acupuncture.
  • Platelet-rich plasma.

Check with your healthcare provider before you try any of these tips. They’ll know what is and what is not appropriate for you depending on the stage of the disease.

You could also try medications, including:

Ask your healthcare provider if it’s OK for you to try the over-the-counter medications and supplements for arthritis of the knee.

Nonsurgical options don’t always work for everyone with knee arthritis. You might need to have a type of surgery, including an:

Most people have stage 4 arthritis when they get surgery.

How long does it take to recover from arthritis of the knee?

Full recovery from arthritis of the knee is not possible. However, it is possible to feel less pain, swelling and stiffness because of medications, physical therapy and other treatments.

Prevention

How can I reduce my risk of arthritis of the knee?

Most known causes of arthritis of the knee are unpreventable and include:

  • Genes.
  • Bone anomalies.
  • Aging.
  • Injuries.

Try to maintain a healthy weight and avoid activities that put a lot of stress on your knees. Get treatment if you have symptoms of arthritis of the knee.

Outlook / Prognosis

Is there a cure for arthritis of the knee?

There is no cure for arthritis of the knee. It’s a lifelong condition. But the good news is treatment can relieve some of the symptoms. Treatment might even slow down or stop the disease from getting worse.

Can arthritis of the knee get worse?

Arthritis of the knee can get worse with time and stress on the joint. Try treatments like medications and physical therapy to ease symptoms and possibly slow down the progress of the disease.

Living With

Will arthritis of the knee affect how I walk?

Pain and stiffness caused by arthritis of the knee can make walking difficult. In the later stages, your knee might even lock up. You might struggle even to move it. See your healthcare provider about treatments that might reduce your risk of such symptoms.

When should I see my healthcare provider?

See your healthcare provider if you have pain, swelling or stiffness in your knees. Look for other symptoms such as warm and red skin and buckling or locking of the knee joint. You might have arthritis of the knee.

What questions should I ask my healthcare provider about arthritis of the knee?

It might be helpful to arrive at your healthcare provider’s office with a list of questions you want or need to be answered. Consider:

  • Do I have arthritis in one knee or both?
  • What type of arthritis do I have?
  • What’s a possible cause of my arthritis?
  • What treatments do you recommend?
  • What medications should I take?
  • Do I need physical therapy?

A note from Cleveland Clinic

Knee arthritis can affect people of all ages. It’s painful, impairs movement and causes swelling of the joint. Some people are so disabled by it that they can’t work anymore. Others can only work after surgery. Meanwhile, for others, the pain isn’t necessarily as bad, but it still prevents them from regular activities like cleaning, gardening and running after their kids.

Arthritis of the knee can decrease your quality of life. The good news is that treatments can lessen the severity of your symptoms. The pain and swelling might not be as bad. See your healthcare provider for evaluation and treatment if you have symptoms.

Last reviewed by a Cleveland Clinic medical professional on 10/18/2021.

References

  • American Academy of Orthopaedic Surgeons. Arthritis of the Knee. (https://orthoinfo.aaos.org/en/diseases--conditions/arthritis-of-the-knee) Accessed 9/13/2021.
  • Arthritis Foundation. Osteoarthritis of the Knee. (https://www.arthritis.org/diseases/more-about/osteoarthritis-of-the-knee) Accessed 9/13/2021.
  • Arthritis Foundation. What is Arthritis? (https://www.arthritis.org/health-wellness/about-arthritis/understanding-arthritis/what-is-arthritis) Accessed 9/13/2021.
  • National Institute of Arthritis and Musculoskeletal and Skin Diseases. What Causes Arthritis? (https://www.niams.nih.gov/health-topics/arthritis#tab-causes) Accessed 9/13/2021.
  • NHS. Osteoarthritis. (https://www.nhs.uk/conditions/osteoarthritis/) Accessed 9/13/2021.

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