Osteoarthritis (OA) also known as degenerative arthritis or degenerative joint disease or osteoarthrosis, is a group of mechanical abnormalities involving degradation of joints,including articular cartilage and subchondral bone. Symptoms may include joint pain, tenderness, stiffness, locking, and sometimes an effusion.Simply put,Osteoarthritis is a form of arthritis that features the breakdown and eventual loss of the cartilage of one or more joints. Cartilage is a protein substance that serves as a "cushion" between the bones of the joints involved.
It commonly affects the hands, feet, spine, and large weight-bearing joints, such as the hips and knees. It usually has no known cause and is referred to as primary osteoarthritis. When the cause of the osteoarthritis is known, the condition is referred to as secondary osteoarthritis.CLASSIFICATION
Osteoarthritis can be classified into either primary or secondary depending on whether or not there is an identifiable underlying cause.
CAUSES
Some investigators believe that mechanical stress on joints underlies all osteoarthritis, with many and varied sources of mechanical stress, including misalignments of bones caused by congenital or pathogenic causes; mechanical injury; overweight; loss of strength in muscles supporting joints; and impairment of peripheral nerves, leading to sudden or uncoordinated movements that overstress joints.However exercise, including running in the absence of injury, has not been found to increase one's risk of developing osteoarthritis. Nor has cracking ones knuckles been found to play a role.
Primary
Primary osteoarthritis is a chronic degenerative disorder related to but not caused by aging, as there are people well into their nineties who have no clinical or functional signs of the disease. As a person ages, the water content of the cartilage decreases as a result of a reduced proteoglycan content, thus causing the cartilage to be less resilient. Without the protective effects of the proteoglycans, the collagen fibers of the cartilage can become susceptible to degradation and thus exacerbate the degeneration. Inflammation of the surrounding joint capsule can also occur, though often mild (compared to what occurs in rheumatoid arthritis). This can happen as breakdown products from the cartilage are released into the synovial space, and the cells lining the joint attempt to remove them. New bone outgrowths, called "spurs" or osteophytes, can form on the margins of the joints, possibly in an attempt to improve the congruence of the articular cartilage surfaces. These bone changes, together with the inflammation, can be both painful and debilitating.
A number of studies have shown that there is a greater prevalence of the disease among siblings and especially identical twins, indicating a hereditary basis. Up to 60% of OA cases are thought to result from genetic factors.Both primary generalized nodal OA and erosive OA (EOA. also called inflammatory OA) are sub-sets of primary OA. EOA is a much less common, and more aggressive inflammatory form of OA which often affects the distal interphalangeal joints and has characteristic changes on x-ray.
Secondary
This type of OA is caused by other factors but the resulting pathology is the same as for primary OA:
-Congenital disorders of joints
-Diabetes.
-Inflammatory diseases (such as Perthes' disease), (Lyme disease), and all chronic forms of arthritis (e.g. costochondritis, gout, and rheumatoid arthritis). In gout, uric acid crystals cause the cartilage to degenerate at a faster pace.
-Injury to joints or ligaments (such as the ACL), as a result of an accident or orthodontic operations.
-Septic arthritis (infection of a joint )
-Ligamentous deterioration or instability may be a factor.
-Marfan syndrome
-Obesity
-Alkaptonuria
-Hemochromatosis and Wilson's disease
-Ehlers-Danlos Syndrome
SIGNS AND SYMPTOMS
The main symptom is pain, causing loss of ability and often stiffness. The "Pain" is generally described as a sharp ache, or a burning sensation in the associate muscles and tendons. OA can cause a crackling noise (called "crepitus") when the affected joint is moved or touched, and patients may experience muscle spasm and contractions in the tendons. Occasionally, the joints may also be filled with fluid. Humid and cold weather increases the pain in many patients.OA commonly affects the hands, feet, spine, and the large weight bearing joints, such as the hips and knees, although in theory, any joint in the body can be affected. As OA progresses, the affected joints appear larger, are stiff and painful, and usually feel better with gentle use but worse with excessive or prolonged use, thus distinguishing it from rheumatoid arthritis.
In smaller joints, such as at the fingers, hard bony enlargements, called Heberden's nodes (on the distal interphalangeal joints) and/or Bouchard's nodes (on the proximal interphalangeal joints), may form, and though they are not necessarily painful, they do limit the movement of the fingers significantly. OA at the toes leads to the formation of bunions, rendering them red or swollen. Some people notice these physical changes before they experience any pain.
OA is the most common cause of joint effusion, sometimes called water on the knee in lay terms, an accumulation of excess fluid in or around the knee joint.
DIAGNOSIS
Imaging
X-rays: Approximately one-third of people with osteoarthritis on X-rays have symptoms such as pain or swelling. X-rays can show narrowing of the space between the joint (articular surface), osteophytes, cyst formation, and hardening of the underlying bone. Scoring systems have been used by doctors to assess the extent of the bony changes on X-rays. Separate scoring systems for the different joints have been studied and found to be predictive of disease status. An important finding from these studies was that the presence of osteoarthritis of the hands was a predictive sign of deterioration of the knee joint. In other words, people with finger joint osteoarthritis were more at risk to show a rapid progression of their knee.
MRI: This study is a complex, noninvasive imaging technique that is unlike X-rays. X-rays provide information mainly on bones. However, MRI is capable of visualizing all structures within the joint. MRI technology is sophisticated and requires an expert to interpret the study.
CT scan: This study may be used to image a joint. CT scanning mainly provides information on the bony structures of the joint but in greater detail than plain X-rays.
Joint fluid analysis: Fluid may be extracted from the knee with a needle and syringe when the diagnosis is uncertain or if an infection is suspected.
TREATMENTS
Self-Care at Home
Lifestyle changes may delay or limit osteoarthritis symptoms. These are common home remedies:
Weight loss: One study suggested that, for women, weight loss may reduce the risk for osteoarthritis in the knee.
Exercise: Regular exercise may help to strengthen the muscles and potentially stimulate cartilage growth. Avoid high-impact sports. The following types of exercise are recommended: range of motion, strengthening, and aerobic.
Diet: While there is no specific osteoarthritis diet, supplements of antioxidant vitamins C and E may provide some protection. Vitamin D and calcium are recommended for strong bones. The recommended daily dose of calcium is 1000 mg-1200 mg. The current guideline for vitamin D is 400 IU per day.
Heat: Hot soaks and warm wax (paraffin) application may relieve pain.
Orthoses: These assistive devices, such as neck braces and knee braces, are used to improve function of moveable parts of the body or to support, align, prevent, or correct deformities. Splints or braces help with joint alignment and weight redistribution. Other examples include walkers, crutches or canes, and orthopedic footwear.
Over-the-counter (OTC) medications:
Acetaminophen (Tylenol) is the first drug recommended for osteoarthritis.
Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used for arthritis pain. These include aspirin, ibuprofen (Motrin or Advil), naproxen (Aleve), and ketoprofen (Orudis).
Newer OTC preparations include chondroitin and glucosamine sulfate, which are natural substances found in the joint fluid. Chondroitin is thought to promote an increase in the making of the building blocks of cartilage (collagen and proteoglycans) as well as having an anti-inflammatory effect. Glucosamine may also stimulate production of the building blocks of cartilage as well as being an anti-inflammation agent. Glucosamine was found to increase blood sugar in animal studies, so people with diabetes should consult their doctor first.
Arthritis self-help course: The Arthritis Foundation offers an educational program on the causes and treatment of arthritis. Exercise, nutrition, relaxation, and pain management programs are covered as well as ways to communicate with your doctor. Completion of the program reduced pain by 20% and doctor visits by 40%
Blood tests: No currently accepted blood test or marker for this disease exists. Blood tests may be drawn in cases in which infection is suspected
Medication
Analgesics
Acetaminophen is the first line treatment for OA. For mild to moderate symptoms effectiveness is similar to Non-steroidal anti-inflammatory drugs (NSAIDs), though for more severe symptoms NSAIDs may be more effective. NSAIDs such as ibuprofen while more effective in severe cases are associated with greater side effects such as gastrointestinal bleeding. Another class of NSAIDs, COX-2 selective inhibitors (such as celecoxib) are equally effective to NSAIDs with lower rates of adverse gastrointestinal adverse effects but higher rates of cardiovascular disease such as myocardial infarction. They are also much more expensive. There are several NSAIDs available for topical use including diclofenac. They have fewer systemic side-effects and at least some therapeutic effect. While opioid analgesic such as morphine and fentanyl improve pain this benefit is outweighed by frequent adverse events and thus they should not routinely be used.
Other
Oral steroids are not recommended in the treatment of OA because of their modest benefit and high rate of adverse effects. Injection of glucocorticoids (such as hydrocortisone) leads to short term pain relief that may last between a few weeks and a few months.Topical capsaicin and joint injections of hyaluronic acid have not been found to lead to significant improvement. Hyaluronic acid injects have been associated with significant harm.
SURGERY
Surgery may relieve pain and improve function.
-Arthroscopy is the examination of the inside of a joint using a small camera (endoscope). -Arthroplasty is the repair of a joint in which the joint surfaces are replaced with artificial materials, usually metal or plastic.
-Osteotomy is incision or cutting of bone.
-Chondroplasty is surgical repair of the cartilage.
-Arthrodesis is a surgical fusion of the bony ends of a joint preventing joint movement. For example, fusion of an ankle joint prevents any further joint movement of the ankle itself. This is done as a result of many years of significant joint pain resulting from a previous significant injury or severe osteoarthritis. The procedure is performed to help block further pain by preventing any further joint movement.
-Joint replacement is removal of diseased or damaged bony ends and replacement with a manmade joint composed of a combination of metal and plastic. Knee joint replacement and hip replacement are the most common. Some joints, such as those of the spine, cannot be replaced presently.
PROGNOSIS
A single prognosis is difficult to establish because of the variety of factors influencing the disease. It also may be important to look at the particular joint involved rather than lumping all the joints together to predict the outcome. Symptoms may not be able to be predicted based on X-rays. But a few studies may predict joint deterioration.
Some findings suggest that the following are true:
Narrowing of the joint space seems to be linked with deterioration of the condition.
The presence of osteoarthritis of the hands is a predictive sign for deterioration of the knee joints.
People with rapid progression seemed to have knee pain upon entry into clinical studies.
Future research into causes of joint pain in patients with osteoarthritis will likely lead to improved treatments. Ongoing scientific studies are encouraging and include work looking at the effects of antibodies against nerve growth factor, which seems to play a role in pain perception in those afflicted by osteoarthritis of the knees and hips
