The knee is the biggest joint in the body, and it carries a lot of weight. As people get older, the task of carrying this weight can wear down the cartilage that covers the ends of the bones in a joint.
Cartilage is the tissue that makes sure the bones pass over each other smoothly. It also acts as a kind of cushion or shock absorber.
If the cartilage wears away, the bones will rub together. This can lead to osteoarthritis (OA), the most common type of arthritis.
OA causes pain, swelling, and stiffness. People with OA of the knee may find it hard to exercise, climb stairs, or even walk.
Symptoms that can appear at the early stages of knee OA are:
Early symptoms of knee OA include pain, swelling, and stiffness.
- Pain, especially on bending and straightening the knee
- Swelling, caused by a buildup of fluid in the joint, or by bony growths called osteophytes that form as the cartilage breaks down
- Warmth in the skin over the knee, especially at the end of the day
- Tenderness when pressing down on the knee
- Stiffness when moving the joint, especially first thing in the morning, or after a period of inactivity
- Creaking or cracking on bending, known as crepitus
Activity can make symptoms worse, leading to pain at the end of the day, especially after a long time of standing.
If the knee is red, the person has a fever, or both symptoms occur, the problem is likely to be a different condition to osteoarthritis.
Treatment of OA depends on how serious the condition is.
There are some home remedies and over-the-counter treatments for OA of the knee that can be used at home and are readily available from the pharmacy. These treatments include:
- Applying heat or cold. Heat relieves stiffness and cold can ease pain. The heating pad or ice pack should be covered with a towel so as not to burn the skin.
- An assistive device, such as a cane or walker, can help take some of the weight off of the knees. Holding the cane in the opposite hand to the painful knee is most effective.
- Pain relief medications are available over the counter. These should always be used with caution as they can cause side effects.
Examples of over-the-counter medications
- Topical creams containing nonsteroidal anti-inflammatory drugs (NSAIDs), or ingredients that create a warming or cooling sensation are a relatively safe way to reduce symptoms.
- NSAIDs such as ibuprofen, naproxen, and aspirin can help reduce swelling and pain. High doses or long-term use can cause stomach upset, heart problems, bleeding, and damage to the liver and kidneys.
- Acetaminophen can help reduce pain but not swelling. Acetaminophen has fewer side effects than NSAIDs, but large doses can damage the liver.
When to see a doctor
For some people, pain and other symptoms are severe enough to interfere with daily life, and over-the-counter medications do not help.
People should see a doctor if their knee pain and other symptoms begin to interfere with daily life.
The next step is to consult a general physician, who may refer the patient to a rheumatologist or orthopedic surgeon.
To find out whether a patient has OA, the doctor may ask:
- When did the pain start?
- Where does it hurt?
- Is there any stiffness, creaking, warmth, or swelling?
- What makes it better? What makes it worse?
- How have you treated it? Did home treatments work?
- How have the symptoms affected daily activities?
The doctor will examine the knees, moving them forward and back to note the range of motion, and to find out which movements cause pain.
There are a number of tests to diagnose osteoarthritis:
- Joint aspiration involves using a needle to draw a sample of fluid from the joint. That fluid is then checked in a laboratory for signs of other joint problems such as gout or infection.
- Magnetic resonance imaging (MRI) can provide detailed images of the person's knees, which may show fluid buildup in the thigh or knee bones.
- X-rays can reveal whether the knee joints have been damaged in the later stages, but may not reveal damage in the early stages.
If tests show that a person has OA, the doctor may prescribe one of the following treatments:
- Steroid injections, injected into the knee joint to reduce inflammation
- Hyaluronic acid injections provide fluid that cushions and lubricates the joint
- Physical therapy involves exercises to improve flexibility and range of motion in the damaged joint
If these solutions do not work, the physician may recommend surgery to replace a severely damaged joint.
Swimming is a great exercise for people with osteoarthritis of the knee.
There are some lifestyle changes that can relieve the pain and stiffness caused by knee arthritis:
- Losing weight can relieve pain and prevent further joint damage
- Exercise is one of the best ways to relieve arthritis pain, especially low-impact exercises such as walking, riding a stationary bicycle, or swimming
Swimming is ideal because the buoyancy of the water takes pressure off the joints, while the warmth soothes them.
Exercise increases motion and flexibility, and strengthens the muscles that support the joints. Exercise also helps people to maintain a healthy weight.
OA is a common but painful condition that affects many people as they age. Pain, stiffness, swelling, warmth, or cracking in the joints may be signs that it is time to seek medical help.