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Knee Arthritis

Learn about knee arthritis types, symptoms, causes and treatment options. Request an appointment for more information.

Knee Arthritis

Arthritis, by definition, means pain or disease of a joint. Knee arthritis encompasses more than 100 different ailments, with osteoarthritis and rheumatoid arthritis being the most prevalent.

What is knee arthritis?

Arthritis, by definition, means pain or disease of a joint. Knee arthritis encompasses more than 100 different ailments, with osteoarthritis and rheumatoid arthritis being the most prevalent.

Arthritis most commonly impacts people 50 years of age and older, but it can pop up much sooner. Roughly 20% of all U.S. adults over 45 years old have arthritis in the knee, which typically worsens with age.

The knee is the strongest and largest joint in the body. Ligaments connect the femur (thighbone), tibia (shinbone), and patella (kneecap). Tendons provide stability to the knee, while cartilage and synovial fluid provide cushioning and keep the bones from rubbing against each other. An arthritic knee can make simple activities painful and more rigorous athletic activities much more challenging.

What are the types of arthritis in the knee?

A variety of conditions can cause arthritic knees. The most common are knee osteoarthritis, rheumatoid arthritis, and posttraumatic arthritis.

A degenerative joint disease, osteoarthritis in the knee is caused by wear and tear. Over time, whether through aging or repeated injuries, the cartilage in the knee starts to fray, lose its smooth nature, and disintegrate. As the cartilage degrades, knee inflammation and pain increase.

This condition is an autoimmune disease where the body attacks its cartilage and ligaments. Typically, rheumatoid arthritis impacts multiple joints throughout the body. Rheumatoid arthritis in the knee can affect both knees at the same time. The autoimmune disease can also cause synovial membrane inflammation, which can increase pain.

Arthritis can develop in multiple parts of the knee following an injury. For example, a bone break can damage cartilage, or a ligament tear can cause stress on other parts of the knee.

What are knee arthritis symptoms?

Pain is the most prevalent symptom of every knee arthritis condition. It typically develops over time but can also occur suddenly. Along with pain, symptoms of arthritis in the knee can include:

  • Swelling or stiffening that makes it more challenging to move the knee
  • Pain that can change with the weather
  • Pain after sitting or in the morning
  • A creaking or clicking in the knee, sometimes leading to the knee locking
  • Instability of the knee from weakness

What are the stages of knee arthritis?

Four different knee arthritis stages show the level of pain progression in the joint:

  • Stage 1: Minor stage with little to no pain early in the development of wear and tear
  • Stage 2: Mild stage with minimal pain and growing stiffness
  • Stage 3: Moderate stage with increased pain. Cartilage has already entered a deteriorated state
  • Stage 4: Severe stage with the most pain. A range of symptoms makes movement difficult

If you are seeing signs of arthritis in your knee, request an appointment with a Mass General Brigham Sports Medicine specialist for a diagnosis and customized treatment plan.

What are causes and risk factors of knee arthritis?

A wide range of causes and risk factors can increase the possibility of developing knee arthritis. Causes of knee arthritis can include:

  • Age, more common in adults over 50
  • Excess weight
  • Sex, older women experience knee osteoarthritis more frequently than men of the same age
  • Overuse and stress
  • Heredity issues, such as bone anomalies or joint laxity
  • Autoimmune disorders

How to diagnose arthritis in the knee

To diagnose knee arthritis, your provider will rely on a physical examination and imaging technology. A physical exam often includes:

  • Questions about the extent of pain, swelling, and tenderness
  • Movement testing to evaluate pain, range of motion, and stability
  • Tests to measure a person's gait (walk), crepitus (grating in the joint), and knee joint

An X-ray image shows the location of the bones and could highlight bone spurs common in knee osteoarthritis or show a diminished gap between bones, a sign of reduced cartilage. A magnetic resonance imaging (MRI) scan offers information on the health of the soft tissue, such as cartilage and ligaments.

With knee arthritis, a provider may also run a blood test to detect conditions like rheumatoid arthritis.

Treatment for knee arthritis

Knee arthritis treatment typically starts with a nonsurgical approach designed to minimize pain. Early in the process, patients can reduce activities that aggravate the pain. Athletes may need to reduce stress on the knee joint by limiting activities that continually pound the knee on hard surfaces, such as running and tennis, and switch to lower-impact activities, such as cycling and swimming.

Other non-surgical approaches to treating knee arthritis include: 

  • Physical therapy to strengthen muscles and increase range of motion in the knee
  • Equipment to reduce pressure on the knee, such as high-quality shoes, a walking assistance device, or a brace
  • Multiple types of medication to treat pain and inflammation

Surgical knee arthritis treatment

Surgery is usually reserved for extreme cases where knee pain turns debilitating. An arthroscopic surgery procedure can help improve knee osteoarthritis by repairing cartilage. Surgery can remove the damaged portion of the cartilage. Surgeons may also be able to use cartilage tissue from elsewhere in the body to repair the meniscus or articular cartilage.

Other surgeries can reshape the bones to ease joint pressure or replace the knee by removing and replacing damaged portions.

Living with knee arthritis

With no cure for knee arthritis, pain management becomes a focus for patients. By reducing risk factors and adhering to treatment protocols, patients may be able to relieve knee arthritis pain.

Proper treatment, especially physical therapy to strengthen the muscles around the knee, can keep symptoms from worsening and relieve arthritis knee pain.

Recovery following surgery depends on the procedure and will include bracing and physical therapy to regain range of motion and stability within the knee joint.

How to prevent arthritis in the knees

Maintaining a healthy lifestyle without undue stress on the knee is the only way to help limit the potential for developing knee arthritis. Many key causes of knee arthritis, including age, genes, and injuries, are unpreventable.


Pain is commonly the first sign of arthritis, along with swelling, stiffness, and clicking.

Any activity that places added pressure on the knee joint, such as walking or running, can further stress the knee and cause pain. Walking may be considered a lower-impact exercise for someone who usually jogs or runs.

Proper treatment can ease the pain of knee arthritis, but arthritis does not go away.

Proper treatment, such as relieving pressure on the knee and strengthening the muscles around the knee, can help slow the progression of knee arthritis.

Arthritis does not show on an X-ray, but an X-ray can show bone issues common with arthritis and the location of the bones, which can highlight the loss of cartilage.

A mix of cardio and strength training can help strengthen the knee and offer additional stability. Combining a weight routine and exercises such as cycling, swimming, and walking (if pain allows) can reduce stress on the knee while building stability.

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