Arthritis refers to several conditions that involve inflammation and damage to a person’s joints. If a person has arthritis in their knee, it may feel stiff and painful.

People with arthritis may feel pain in their joints due to inflammation. This may result in a person having difficulty performing everyday activities.

Arthritis can affect any of the joints in a person’s body. However, arthritis is particularly common in the knees.

Experts note that around 13% of females and 10% of males aged 60 years and older experienced symptomatic knee osteoarthritis (OA). Additionally, symptomatic knee OA may affect up to 40% of people over 70 years old.

This article explores how knee arthritis pain may feel, its causes and treatments, and when someone should speak with a doctor.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

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According to the Arthritis Foundation, arthritis may cause a person to experience pain, stiffness, and swelling in the knee. It may interfere with daily activities, such as climbing stairs or walking.

Knee arthritis may cause a person to experience different types of pain, such as:

  • knee pain that worsens over time
  • pain in the knee that is worse in the morning or after resting
  • pain in both knees
  • pain after vigorous activity
  • sudden knee pain that peaks after 4–12 hours
  • pain lasting for weeks at a time
  • increased joint pain with changes in the weather

Other symptoms

Knee arthritis can cause other symptoms as well as pain. These symptoms include:

  • stiffness and swelling that makes bending the knee difficult
  • swelling that is worse in the morning or after resting
  • “locking” or “sticking” of the knee during movement
  • creaking, clicking, snapping, or grinding of the knee during movement
  • weakness or buckling in the knee

Many types of arthritis may affect a person’s knee. Different types of arthritis may cause knee pain in different ways.

Osteoarthritis

OA is the most common form of arthritis. It occurs due to cartilage breaking down on the ends of the bones that form joints. Cartilage is a form of tissue that protects the bones and allows them to slide over each other.

When cartilage in a joint wears away, the bones rub against each other. This can lead to pain, stiffness, and loss of motion in the joint.

According to the Arthritis Foundation, knees are one of the joints most commonly affected by OA.

Rheumatoid arthritis (RA)

RA is an autoimmune disease. This means that a person’s immune system mistakenly attacks healthy tissues.

A person with RA may experience joint pain, inflammation, and loss of function in the joints. In general, RA affects both sides of a person’s body. Therefore, if RA affects one knee, it likely affects the other knee too.

Psoriatic arthritis (PsA)

PsA is an autoimmune condition that typically affects people who have the skin condition psoriasis. It may cause scaly, inflamed patches of skin to develop on a person’s scalp, knees, or elbows. It may also cause joint pain, swelling, and stiffness in the neck, hips, and lower back and painful swelling in a finger or toe.

Gout

Gout is a form of arthritis that develops due to a buildup of uric acid crystals in a person’s bloodstream. Uric acid is a waste product that forms when the body breaks down purines, which are present in meat and meat products.

When uric acid builds up in a person’s body, it forms needle-like crystals in joint tissue. This may cause severe pain, which some people may feel for several weeks. However, the pain typically peaks between 4-12 hours.

The first sign of gout is intense pain and swelling in the big toe. However, it may also cause pain in a person’s knees.

Reactive arthritis

Reactive arthritis typically occurs following an infection of a person’s genital, gastrointestinal, or urinary system. It may cause pain and swelling in the knees, shoulders, and hips.

Infectious arthritis

Infectious, or septic, arthritis develops when an infection from another part of the body spreads to a joint. Typically, bacteria traveling through the bloodstream cause infectious arthritis, but fungi or viruses may also cause the condition.

The Arthritis Foundation notes that infectious arthritis typically affects the knees.

Post-traumatic arthritis

Post-traumatic arthritis occurs after an injury to a person’s knee. Injuries that damage a person’s joints can lead to arthritis over time.

Damage to cartilage in the knee or ligament injuries can cause wear on a person’s knee joint, which may lead to post-traumatic arthritis.

Juvenile arthritis

Juvenile arthritis develops in children and adolescents under the age of 16. Several types of juvenile arthritis can cause swelling and pain in the knees.

There is no cure for arthritis. However, various treatments and lifestyle modifications may help ease symptoms, such as:

It is a good idea to talk with a healthcare professional about which treatments are most suitable.

The American Academy of Orthopedic Surgeons notes that knee arthritis can cause people to miss work due to pain or difficulty moving. Without treatment, knee arthritis may become worse and eventually cause disability.

Therefore, it is important to consult with a doctor if someone experiences any symptoms of knee arthritis. A doctor can diagnose the cause of the symptoms and discuss the proper treatment for their condition.

Many types of arthritis may affect a person’s knee. Arthritis pain in the knees may develop over time or develop suddenly.

In addition to pain, knee arthritis may cause swelling, stiffness, and reduced mobility. If a person has any symptoms of knee arthritis, they should speak with their doctor.