Degenerative joint disease or osteoarthritis
What is spondylosis (osteoarthritis)?
Osteoarthritis is a disease that primarily affects the lining of the joints (the hyaline cartilage), and the bones associated with the joints (the subchondral bones). However, all the tissues surrounding the affected joint eventually become abnormal. The cartilage lining the joint frays and outgrowths of bone form around the joint in an attempt at healing. Fragments of this bone break off and irritate the joints, which lose their natural lubrication and become stiff and noisy.
What causes osteoarthritis?
Osteoarthritis used to be seen as a result of wear and tear of the joints. In fact the disease is now thought to have several subtypes, of which some are more aggressive and related to immune mechanisms, resulting in inflammation against self and a rapid erosion of the cartilage and adjacent bone – called erosive osteoarthritis.
The mechanism is a complex system of interacting mechanical, biological, biochemical and enzymatic feedback loops. When one or more of these fail, osteoarthritis occurs. Anything that changes the microenvironment of the bone cell may initiate the chain of events which lead to osteoarthritis – congenital joint abnormalities, genetic defects, infectious processes, metabolic processes, and endocrine (glandular) and neurological disease. Trauma to a joint may initiate osteoarthritis, including prolonged overuse of a joint or group of joints.
Who gets osteoarthritis and who is at risk?
Osteoarthritis is the most common of all disorders of the joints. It first appears, but without symptoms, in the 20s and 30s and becomes almost universal by the 70s. Almost all people have some sort of pathological changes in the weight-bearing joints by the time they are 40, although relatively few people have symptoms at this age.
Men and women are equally affected, although men tend to get symptoms earlier. There is a strong hereditary tendency, especially when hand joints are involved in women. There is also a perimenopausal, possibly hormonal related association. The earlier the onset and the greater the genetic factors, the greater the risks. Being overweight often speeds up the process of osteoarthritis to the knees and the hips.
Symptoms and signs
The joints most commonly affected are the hips, knees, back and small joints of the fingers. Initially osteoarthritis may be associated with an inflammatory process and the onset is seen with mild swelling and stiffness in the hands and affected joints. It is usually subtle and gradual. Pain is the earliest symptom, made worse by exercise. The stiffness is transient. Usually it is short lived in the morning (less than 30 minutes) and after periods of sitting or inactivity. It usually improves with exercise.
As the disease progresses, the motion of the joints is decreased and the person may notice tenderness and grinding noises in the joint. The joint eventually enlarges from bony outgrowth. The swelling at this stage is irreversible. As the ligaments become lax, the joint has increased instability with more pain. Tenderness to the touch and pain when the doctor moves the joint are signs of advanced disease. At this stage muscle spasm and contraction of the muscles around the joints add to the pain. Osteoarthritis of the hip is characterised by increasing rigidity and loss of range of motion. This is in contrast to osteoarthritis of the knee in which the ligaments become lax.
How is osteoarthritis diagnosed?
Diagnosis is usually based on the symptoms, signs and X-ray changes. Blood studies are used mainly to rule out other causes of arthritis. However, these are not reliable as they can be normal even in the presence of such diseases as gout and rheumatoid arthritis. X-rays can also be normal early on. Therefore a clinical examination is the most important aspect of the diagnosis – not the blood tests.
Can osteoarthritis be prevented?
No, however, by remaining active and taking care not to become overweight, the severity of the disease can be lessened. However, early identification of risk factors is important
How is osteoarthritis treated?
Patient education is particularly important. In spite of pain, it is important to keep active. Exercise maintains range of motion, and develops the stress-absorbing muscles and tendons. Daily stretching exercises are very important. Periodic partial or complete immobilisation of a joint for relatively short periods can accelerate osteoarthritis and worsen the clinical outcome. Interestingly, osteoarthritis of the hips and knees can be stopped from progressing by a well-planned exercise regime. People should take care not to sit in soft chairs or sleep on soft mattresses, avoid sitting in a slumped position and continue to be as active as possible.
These are divided into symptomatic and disease modifying therapies. Symptomatic therapies include analgesics – painkillers; such as paracetamol, and paracetamol / codeine preparations or even stronger opiate type drugs, such as tramadol or dextropropoxyphene, which treat pain alone. Antiinflammatories, NSAIDs, which treat inflammation and pain, include aspirin and other non-steroidal anti-inflammatory drugs. These are potentially hazardous to the stomach. Newer safer drugs called COXIBs are available, including celecoxib and rofecoxib. These are much safer than the older NSAID drugs, with less toxicity to the lining of the stomach.
Oral cortisone is not helpful in osteoarthritis, but cortisone injections into the joint are useful when there are signs of inflammation. However, these are usually only needed occasionally.
Disease modifying therapy is controversial. However, there is good evidence that glucosamine sulphate has an established role to play here. The trials show that glucosamine sulphate may even increase cartilage over a three to five year period. Trials do not show this effect from glucosamine hydrochloride, and therefore it is important to read the labelling of the product to ensure the correct constituents. It is made from shrimp and crab shells and can therefore not be used if the patient has seafood allergy. Chondroitin sulphate (made from bovine cartilage) may add some small further benefit, but this is not a large degree and adds a significant price to the product.
Drugs such as antimalarials, tetracyclines and metalloproteinase inhibitors are in trials for disease modification in osteoarthritis.
Hyaluronan injections are lubricants similar to joint fluid, made from rooster comb. These are expensive and are not proven to work. They are therefore not currently recommended for widespread use.
Surgery for damaged joints is very successful, with hip and knee replacements now commonplace operations. Hip replacement restores mobility and relieves pain in at least 95 percent of cases. Hip replacements last for about ten years. Other joints, such as the small joints of the fingers and even the shoulder joint are also being replaced with increasing success. The next few years should see these operations becoming increasingly common. Indication for surgery is joint pain non-responsive to medical therapy, or function impairment. Age alone is not a contraindication to surgery.
What is the outcome of osteoarthritis?
With the correct approach of remaining active and keeping a check on weight, osteoarthritis need not become a disabling condition. However, the damage to the joints usually starts before symptoms arise, making it difficult to act early and so prevent further damage.
When to see your doctor
Consult your doctor if:
- A joint is becoming increasingly painful and swollen.
- You experience sudden extreme pain or immobility in a joint.
- You have experienced pain and swelling in your knee(s) and it now starts to give way on movement, particularly when going up and down stairs.
- You know that you have osteoarthritis of your weight-bearing joints, are overweight and would like some advice on weight loss and exercise.
(Reviewed by Dr David Gotlieb, rheumatologist)