Also known as degenerative arthritis, degenerative joint disease, and osteoarthrosis, osteoarthritis (OA) is the most common joint disorder in the United States (U.S.).
It affects around 10 percent of men and 13 percent of women aged over 60 years.
OA is a progressive disease. Symptoms worsen over time.
There is no cure, but treatment can help the individual control pain and swelling, and stay mobile and active.
Contents of this article:
Here are some key points about osteoarthritis.
- Osteoarthritis (OA) is a common cause of joint damage, especially in the hands, hips, knees, lower back, and hands.
- Symptoms normally begin after the age of 40 years, but they can affect younger people after a traumatic injury.
- OA is more likely to affect women than men after the age of 50 years.
- Symptoms progress slowly and contribute to workplace disability and reduced quality of life.
- The average direct cost of osteoarthritis in America is about $2,800 per patient annually.
Osteoarthritis leads to pain and stiffness in the joints.
The main symptoms of OA are pain and difficulty moving the affected joints.
The person may feel stiff on waking up in the morning, but this usually improves within 30 minutes of starting to move about.
- bony growths around the edges of joints
- damage and loss of cartilage, the part of the joint that cushions the ends of the bones and allows easy movement of joints
- synovitis, a mild inflammation of the tissues around the joints
Some people have no symptoms. Symptoms may occur in one more joints, and they tend to appear gradually.
The individual may also notice that:
- the affected joints are larger than usual
- pain and stiffness worsen after not moving the joint for a while
- joints feel warm and tender
- there is a loss of muscle bulk
- affected joints have a limited range of movement
A grating or crackling sound or sensation may occur in the affected joint.
Effects on the joints
The knees, hips, hands, lower back, and neck are most commonly affected, but osteoarthritis can occur in any joint.
Both knees are normally affected, unless the OA was caused by an injury or another condition.
There will be pain when walking, especially uphill or upstairs.
Knees may lock into position, making it harder to straighten the leg. The knee may make a soft, grating sound when used.
Anything that requires movement of the hip joint causes problems, such as getting in or out of a car, or putting on shoes and socks.
Pain in the hip is common, but some patients with OA in the hips experience pain in their knee instead of their hip, or, less commonly, in the thighs, ankles and buttocks.
Pain is often felt whilst walking, but it can be present when resting.
OA can affect:
- the base of the thumb
- the top joint of the fingers, closest to the nail
- the middle joint of the fingers
Fingers may be stiff, swollen, and painful. Bumps may develop on the finger joints.
In some cases, finger pain decreases and eventually goes away, while the swelling and bumps remain.
The fingers may bend slightly sideways at the affected joints. Fluid-filled lumps, or cysts, may develop on the backs of the fingers. These are often painful.
A bump may develop where the base of the thumb joins the wrist. This can make writing, turning keys, and opening jar-tops difficult and painful.
If joint stiffness and swelling lasts for more than 2 weeks, the person should see a doctor.
Those who are already taking medication for OA should contact a health care professional if they experience nausea, constipation, drowsiness, abdominal discomfort, or have black or tarry stools.
Causes and risk factors
OA happens when the body is not able to repair joint tissue in the usual way.
A traumatic injury to a joint, for example, may undermine the body's ability to carry out proper repairs is undermined, so damage to the affected joint persists and worsens, leading to symptoms of OA.
OA can develop as a result of cartilage damage. Cartilage is the protective surface that cushions the ends of bones in joints and allows the joints to move smoothly.
The smooth surface of the cartilage becomes rough, causing irritation. As the cartilage wears down, the bone in the joint rubs against another bone, causing damage and pain.
The bones start protruding, forming bony lumps called osteophytes, and the joints may become knobbly.
As a result, the bones gradually thicken and become broader, and the joints become stiffer, less mobile, and painful.
If fluid accumulates in the joints, they will swell.
Why the repair process breaks down remains unclear, but several contributory factors may be involved, including injury or surgery, overuse, and damage resulting from rheumatoid arthritis (RA) .
It may take several years for OA to appear after an injury.
Secondary OA is a condition that develops because of damage or another condition.
OA is more common among females than males, especially after the age of 50 years.
Symptoms are more likely to appear after the age of 40 years, but it can affect younger people after a traumatic blow or sports injury, especially to the knee, or as a result of another joint condition.
Having joint or cartilage defects from birth significantly increases the risk of eventually developing osteoarthritis.
Obesity puts greater strain on weight bearing joints, and increases the risk.
Jobs that involve repetitive movements in a particular joint make OA more likely.
Some diseases and conditions that increase the chance of developing OA are:
- rheumatoid arthritis
- Paget's disease of the bone
- septic arthritis
- poor alignment of the knee, hip, and ankle or limb-length inequality
Inherited genetic factors may play a role in 50 and 65 percent of cases of hand, hip, and knee osteoarthritis, but the exact genes have not yet been identified.
A doctor will ask the patient about symptoms and carry out a physical examination.
OA commonly affects the knees. An x-ray may show bone damage as a result of the cartilage wearing away.
There is no definitive test that can diagnose OA, but imaging tests may show if damage has occurred.
Tests may include:
X-rays: These may reveal bone spurs around a joint, or a a narrowing space within a joint, suggesting that cartilage is breaking down.
MRI scan: This can help the doctor determine what is causing pain.
Joint fluid analysis: Also known as arthrocentesis, this involves using a sterile needle to withdraw fluid from an inflamed joint, for analysis in a lab.
If uric acid crystals are present, this may indicate gout. This test can also determine whether there is inflammation or an infection.
Blood tests may help rule out other conditions, such as rheumatoid arthritis.
There is no cure for OA, but treatment can help relieve symptoms and maintain joint movement.
Interventions include exercise, manual therapy, lifestyle modification, and medication.
Medication cannot reverse damage, but it can help reduce pain.
Acetaminophen (paracetamol, Tylenol): These can relieve pain in patients with mild to moderate symptoms.
High doses can cause liver damage, especially if the patient regularly consumes alcohol, so it is important to follow the recommended dosage.
Acetaminophen may also affect how some other medications work, so it is important for patients to tell the doctor if they are taking it.
Non-steroidal anti-inflammatory drugs (NSAIDs): If acetaminophen is not effective in controlling pain, the doctor may prescribe a stronger painkiller, which may include ibuprofen, aspirin, or diclofenac.
Some topical NSAIDs can be applied directly onto the skin of the affected joints.
Some over-the-counter (OTC) topical NSAIDs are very effective at reducing pain and swelling in the joints of the knees or hands.
Tramadol (Ultram): This is a prescription analgesic that does not reduce swelling but provides effective pain relief with fewer side effects than NSAIDs.
It is typically used for short-term acute flare ups, and it may be prescribed alongside acetaminophen for more powerful pain relief.
Codeine: This may help with more severe symptoms.
There is a risk of dependence, but in cases of severe pain, this may be an option. Side effects may include constipation and drowsiness.
Capsaicin cream: This medication blocks the nerves that send pain messages. It may help patients with OA in their hands or knees that does not respond well to topical NSAIDs.
Pain relief is not immediate, and it can take 2 weeks to a month for the medication to take full effect.
A tiny amount of capsaicin cream is applied to the affected joints four times daily and no more than once every 4 hours.
The first application may trigger a burning sensation, but, after some uses, that sensation goes away.
Capsaicin cream is made from chillies. If it comes into contact with the eyes, mouth, nose or genitals, there will be no damage, but it will probably cause pain. It should not be applied to broken or inflamed skin, and hands must be washed after use.
Avoid having a hot bath or shower before or after applying the cream.
Intra-articular cortisone injections: Severe pain can be treated by injecting a medication, usually a corticosteroid, directly into the site of the joint.
These are effective at relieving pain and swelling, but can normally be applied only once every 4 months in a single joint.
Too many intra-articular injections can damage the joint, and overuse of corticosteroids increases the risk of osteoporosis and other adverse effects.
Transcutaneous electrical nerve stimulation (TENS) applies an electrical current through the skin. It controls pain by numbing some of the nerves endings in the spinal cord. A TENS unit is usually connected to the skin using two or more electrodes.
Thermotherapy uses warm and cold temperatures to help reduce pain and stiffness in the joints.
A hot water bottle filled with either hot or cold water, or hot and cold packs, can be applied to the affected area. Hot and cold packs can be cooled in a freezer or heated in a microwave.
Manual therapy is performed by a physical therapist. Stretching techniques help keep the joints flexible and supple. Not using the affected joint may weaken the muscles, further worsening osteoarthritis stiffness.
Problems with the lower limbs
People whose hips, knees or feet are affected may benefit from special footwear, or shoe-insoles.
Some shock-absorbing soles can reduce the pressure on the joints. Special insoles may help distribute bodyweight more evenly.
Wearing leg braces, or holding a stick or cane on the opposite side of the body to the affected leg, may help.
A splint can help the patient rest a painful joint. A splint is a piece of rigid material that provides joint or bone support.
Surgery is not usually necessary, but it may help if OA affects the hips, knees, joints, and the base of the thumbs.
It is only usually recommended if other therapies have been ineffective, or if one of the joints is severely damaged.
Arthroplasty, or total joint replacement: The damaged parts are surgically removed and a prosthesis, or artificial joint, made of metal and plastic, is inserted.
The most commonly replaced joints are the hip and knee joints, but implants can also replace the joints in the shoulder, finger, ankle, and elbow.
Arthroplasty is usually effective, improving both appearance and function and allowing the patient to use the joint actively and painlessly.
There is a small risk of infection and bleeding. Sometimes a joint may come loose or wear down, and eventually need replacing.
Arthrodesis: the joint may be realigned, stabilized, or surgically fixed to promote a bone fusion. This increases stability and reduces pain.
If the joint in the ankle is fused, the patient will be able to put weight on it painlessly, but it will have no flexibility.
Osteotomy: The surgeon adds or removes a small section of bone either above or below the knee joint.This can realign the leg so that the patient's weight is no longer focused on the damaged part of the joint.
It may be used in patients who are too young for knee replacement surgery.
Osteotomy can help relieve symptoms significantly, but knee replacement surgery may be needed later on.
A range of strategies can help ease the symptoms of OA. A doctor or physical therapist can offer advice on lifestyle changes.
Exercise and weight control
Exercise is a key part of OA treatment. This can help keep the patient mobile, prevent weight gain, build up muscles, and reduce stress.
Exercise in a swimming pool enables muscle strength to be maintained without putting too much weight on the joints.
Patients can exercise at home or in a gym, many of which have the facility to help people with arthritis.
The patient must follow the program carefully, and do appropriate exercises in the correct way, to avoid damage.
The plan will probably focus on improving:
- flexibility and range of movement
- strength and muscle tone
- fitness and stamina, for example through swimming, walking, or cycling
Aquacise, or exercise in a swimming pool, is a good way of exercising without putting additional pressure on joints.
Exercise can also help the patient lose weight, reducing stress on the joints, especially in the lower limbs.
Other ways to manage symptoms include adjustments to furniture, such as raising a chair, and devices for daily activities, for example, a lever that makes it easier to turn on a faucet.
A physical therapist can advise on what is available.
Mobility problems can lead to stress and a higher risk of trips and falls, with subsequent injuries.
Work can become difficult, leading to frustration, irritability, and depression. An occupational therapist may help, and employers can sometimes make adjustments.
Septic arthritis is a joint inflammation caused by bacteria. Joint replacement surgery slightly increases the risk of infection.
This is a medical emergency, and hospitalization is necessary. Treatment involves antibiotic medication and drainage of the infected joint fluid from the joint.