Arthritis characterized by erosion of articular cartilage, either primary or secondary to trauma or other conditions, which becomes soft, frayed, and thinned with eburnation of subchondral bone and outgrowths of marginal osteophytes; pain and loss of function result; mainly affects weight-bearing joints, is more common in older persons.
Alternatuive Names: Degenerative arthritis, degenerative joint disease, and osteoarthrosis.
Osteoarthritis is a disease that affects joints in the body. It can involve any joint, but usually concerns hands and weight-bearing joints such as hips, knees, feet and spine.
Joints are parts of body where one bone meets the other and movement occurs such as elbow, knee, hip and ankle. Backbone or spine also has large numbers of small joints, which allow us to move our neck, and back in all possible directions. Ends of bone which meet each other at joint are covered by cartilage. Cartilage is white, smooth, glistening material and is very specialized which functions as a cushioning material and a shock absorber so that hard bones do not rub against each other, and the cartilage also reduces friction during joint movement since its surface is very smooth. In fact no man made material can match the low friction and shock absorbing properties of healthy cartilage in the joint.
Cartilage is made up of tough fibres of a protein called collagen – Enmeshed in these fibres of collagen are the large molecules of another protein called proteoglycan. Proteoglycan molecules contain lot of water in their interior. Water keeps on moving in and out of the domain of proteoglycan molecules almost like water being sucked in and squeezed out of sponge. This property of ability to exchange water so easily gives an elastic characteristic to the cartilage. Collagen fibres give desired strength and proteoglycan molecules allow reversible compression. The combined structure thus makes up for the tough but not too rigid quality needed for this very specialized tissue.
The bone ends with cartilage covering are enclosed in a membrane called synovium. The synovium releases a slippery fluid know as synovial fluid and this fluid further reduces the friction between moving surfaces capped with cartilage and ensures that the joint moves easily and smoothly. The synovial fluid or joint fluid formed by synovial membrane is a special type of fluid that behaves like fluid when the joint is being moved and during walking when the joint is loaded its character changes to something like jelly to act as an additional shock absorber. The synovial fluid nourishes the cartilage. The cartilage has no blood vessels and relies on synovial fluid moving in and out to provide nutrients and take away the waste products.
Ends of bone, cartilage and synovium are further enclosed in a layer of tissue called capsule. Capsule is a thick and strong tissue but is capable of stretching when joint moves. The combination of bone ends with cartilage covering, synovium and capsule is the joint. The joint is further covered by muscles and tenders, which support the joint and also provide the power to move the joint.
In osteoarthritis changes occur both in the cartilage and the synovial fluid. Changes in the cartilage are easily seen even without microscope and are therefore well known, whereas changes in the synovial fluid are not discernible without the use of specialized tests and equipments. The synovial fluid changes in character and composition and it loses its characteristic capacity to behave in a jelly like manner and act as a shock absorber when the joint is loaded. The cartilage therefore has to sustain more load and impact.
At the same time the cartilage also undergoes subtle changes in chemical composition in a way that proteoglycans decrease and water content increases. As a result the collagen fibrils become disrupted and disorganized. The cartilage has now become soft due to disorganization of tight collagen fibrils, and also swollen due to increased water content. It has thus become less resistant to forces gradually develops cracks or fissures, breaks into fragments usually known as fibrillations, becomes thin and completely disappears in places.
Causes and Risk Factors:
No one knows for sure what causes Osteoarthritis, although scientists are well on their way to understanding the events that lead to the breakdown of cartilage. Researchers now think that there are several factors that may increase your risk for getting OA. Key risk factors include: heredity, excess weight, injury, and joint damage from another type of arthritis.
Damage due to Osteoarthritis progresses slowly over time and may result in several problems. You may have pain, especially when moving a joint. Sometimes, you may hear a grating sound when the roughened cartilage on the surface of the bones rubs together. Bumps or swelling may appear, especially on the fingers and feet. A joint may feel sore and stiff, and the joint won’t move as easily or as far as it once did. All these changes can make it hard to move around and to do everyday tasks, such as opening a jar or walking up stairs.
Establishing the correct diagnosis is very important, because something can be done to manage most forms of arthritis, and most therapies work best when started early in the disease.
Your doctor may be able to diagnose OA based on your medical history and a physical examination. Sometimes, your doctor may order certain tests to help confirm the diagnosis, to determine how much joint damage exists, or to distinguish among different types of arthritis. These tests may include x-rays, blood tests or joint fluid tests.
X-rays: X-ray images of your affected joint may reveal a narrowing space within a joint, which indicates that the cartilage is breaking down. An X-ray may also show bone spurs around a joint. However, many people have X-ray evidence of osteoarthritis before they experience any symptoms.
Magnetic Resonance Imaging (MRI): MRI uses radio waves and a strong magnetic field to produce detailed images of bone and soft tissues, including bone cartilage. This can be helpful in determining what exactly is causing your pain.
Blood tests: Blood tests may help rule out other causes of joint pain, such as rheumatoid arthritis.
Joint fluid analysis: Your doctor may use a needle to draw fluid out of the affected joint. Examining and testing the fluid from your joint can determine if there’s inflammation and if your pain is caused by gout or an infection.
There’s no known cure for osteoarthritis, but treatments can help to reduce pain and maintain joint movement so that you can go about your daily tasks.
Over-the-counter pain relievers can help with symptoms. Most doctors recommend acetaminophen (Tylenol) first, because it has fewer side effects than other drugs.
If your pain continues, your doctor may recommend nonsteroidal anti-inflammatory drugs (NSAIDs). These drugs help relieve pain and swelling. Types of NSAIDs include aspirin, ibuprofen, and naproxen.
However, long-term use of NSAIDs can cause stomach problems, such as ulcers and bleeding. These drugs may also increase the risk for heart attacks and strokes.
The prescription drug, Celebrex (a COX-2 inhibitor) may work as well as other NSAIDs. Because of a risk for heart attacks and stroke, it is given only at the lowest possible dose for the shortest possible period of time.
Corticosteroids injected right into the joint can also be used to reduce swelling and pain. However, relief only lasts for a short time.
Many people use over-the-counter remedies such as glucosamine and chondroitin sulfate. There is some evidence that these supplements can help control pain, although they do not seem to grow new cartilage. Some doctors recommend a trial period of 3 months to see whether glucosamine and chondroitin work.
Capsaicin (Zostrix) skin cream may help relieve pain. You may feel a warm, stinging sensation when you first apply the cream. This sensation goes away after a few days of use. Pain relief usually begins within 1 – 2 weeks.
Artificial joint fluid (Synvisc, Hyalgan) can be injected into the knee. It may relieve pain for 3 – 6 months.
Other Treatment Include:
Try braces or shoe inserts: Consider trying special splints, braces, shoe inserts or other medical devices that can help reduce your pain. These devices can immobilize or support your joint to help you keep pressure off it.
Exercise: Muscles and the other tissues that hold joints together weaken when they aren’t moved enough, so the joint loses its shape and function. Exercise helps lessen the symptoms of Osteoarthritis and can help make you feel better overall. Moderate stretching exercises will help relieve the pain and keep the muscles and tendons around the affected joint more flexible and strong. Low-impact exercises like swimming, walking, water aerobics and stationary bicycling can all reduce pain while maintaining strength and flexibility. While these measures won’t stop the disease from progressing, they can help slow damage to your joints. Combined with good medical care, you can better manage your symptoms.
Surgical procedures include:
Joint replacement: In joint replacement surgery (arthroplasty), your surgeon removes your damaged joint surfaces and replaces them with plastic and metal devices called prostheses. The hip and knee joints are the most commonly replaced joints. But today implants can replace your shoulder, elbow, finger or ankle joints. How long your new joint will last depends on how you use it. Some knee and hip joints can last 20 years. Joint replacement surgery can help you resume an active, pain-free lifestyle. In smaller hand joints, it can also improve appearance and comfort and may improve your joint’s mobility. Joint replacement surgery carries a small risk of infection and bleeding. Artificial joints can wear or come loose and may need to eventually be replaced.
Viscosupplementation: Injections of hyaluronic acid derivatives (Hyalgan, Synvisc) may offer pain relief by providing some cushioning in your knee. These treatments are made of rooster combs and are similar to a component normally found in your joint fluid. Viscosupplementation is only approved for knee osteoarthritis, though researchers are studying its use in other joints.
Realigning bones: Surgery to realign bones may relieve pain. These types of procedures are typically used when joint replacement surgery isn’t an option, such as in younger people with osteoarthritis. During a procedure called an osteotomy, the surgeon cuts across the bone either above or below the knee to realign the leg. Osteotomy can reduce knee pain by transferring the force of the joint away from the worn-out part of the knee.
Fusing bones: Surgeons can also permanently fuse bones in a joint (arthrodesis) to increase stability and reduce pain. The fused joint, such as an ankle, can then bear weight without pain, but has no flexibility. Arthrodesis may be an option if you experience severe pain in your joint, but can’t undergo joint replacement surgery.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.