Osteoarthritis of the Knee
Osteoarthritis is the most common form of arthritis, afflicting more than 21 million people in the United States. As America continues to age, some estimates suggest that as many as 70 million or 20 percent of Americans will suffer from some form of arthritis by 2030.1 Osteoarthritis (OA) of the knee is one of the five leading causes of disability among seniors, and the risk for disability is just as great as that from cardiovascular disease. Pain drives the treatment of osteoarthritis and, after years of dealing with increasing discomfort, many patients eventually have total knee replacement surgery. With gradually thinning cartilage and changing joints, joint cartilage eventually deteriorates and daily activity for patients with OA Knee becomes very painful. Treatment options may include prescription drugs, diet and exercise changes, and joint fluid therapy.2
According to the American Academy of Orthopedic Surgeons (AAOS), osteoarthritis may develop in knees that have experienced trauma, infection, injury or, more commonly, arise de novo without precipitating cause as people age. Factors like heredity, weight, age and gender can predetermine an individual for osteoarthritis. For example, women over the age of 50 are more likely to develop OA than men over the age of 50. Also, those with occupations that require kneeling or squatting are more prone to develop OA. It is also more prevalent in soccer players, tennis players, and long-distance runners.2
In a normal knee, cartilage provides a smooth surface so bones can move easily across each other. There is a high concentration of hyaluronan in the synovial fluid that nourishes, cushions, and lubricates the joint. In a knee with OA, the cartilage begins to deteriorate in the early stages of the disease, and the joint space between the bones narrows considerably. This results in the formation of bone spurs by the surrounding bone called osteophytes. At this stage, the synovial fluid has a very low concentration of hyaluronan and is not able to protect the joint. Gradually the joint changes and the articular cartilage continues to fade until the bone ends scrape against each other and the joint becomes deformed. This is when activity for OA patients is the most strained and painful.3 See Figure 1 for comparison of a healthy joint to one ravaged by OA.
Often, patients experiencing mild to moderate pain may report the symptoms to their doctor. Physicians often ask a few questions to determine the source of the pain:
- Is your knee stiff in the morning?
- Does your knee hurt when you move?
- Does your knee hurt when you are not moving?
- Do you hear a crackling sound or have a grating feeling?
- Is the skin around your knee red and swollen?3
X-rays (see Figure 2) are also used to see how far the disease has progressed and, if a patient is found to have OA of the knee, they will join 21 million other Americans on the route to finding the right course of treatment.4
Pain Management Modalities
Because there is no cure for osteoarthritis, treatment is focussed on alleviating pain and improving the quality of life and mobility of the patient. The American College of Rheumatology recommends a sequence of treatments depending on the severity of pain caused by osteoarthritis.5
Exercise and Weight Loss. One of the main causes of osteoarthritis is stress on the knee joints caused by obesity and too much pressure on the body. A regime of a healthy diet and exercise can help a patient lose weight and lessen the pain pressure on the patient’s knees. In fact, even if one doesn’t currently have osteoarthritis, weight loss of as little as 11 pounds can reduce the risk of developing knee osteoarthritis by 50%. Physicians may prescribe a light exercise regime of low-impact sport for 30-60 minutes, three times a week. Some patients may also choose to brace their knee during exercise for added comfort. Moderate physical activity at least three times a week can reduce the risk of arthritis-related disability by 47%.4
Analgesics and Anti-Inflammatories. If exercise and diet changes don’t alleviate discomfort, many patients turn to over-the-counter pain medication and anti-inflammatories for relief. While at first, acetaminophen, aspirin or ibuprofen may be a good source for pain relief; most OA Knee sufferers will eventually need more potent analgesics to control their pain. COX-2 inhibitors, the latest in nonsteroidal anti-inflammatory drugs (NSAIDs), are drugs that inhibit an enzyme involved in inflammation but spare COX-1, which limits gastrointestinal toxicity. The only COX-2 inhibitor still on the market in the United States is Celecoxib. Rofecoxib and Valdecoxib were taken off of the market in September 2004 and April 2005, respectively.6
Corticosteroids are another common form of treatment for osteoarthritis. This is a medication that is injected into a joint that is swollen and painful, as opposed to being taken orally. These drugs are primarily targeted towards lessening inflammation and decreasing pain over a short amount of time. These steroid injections can only be administered three or four times a year to the same joint, and there are several side effects involved such as fluid retention, weight gain, nervousness, and high blood pressure.7
Knee Replacement Surgery. Many physicians argue that a total knee replacement is the only way to return the most quality of life to patients with osteoarthritis of the knee. However, surgery is very costly. The cost of a total knee replacement and the hospital stay can amount to $30,000.8 A study presented at the 73rd Annual Meeting of the American Academy of Orthopedic Surgeons (AAOS) predicts that the demand for such surgeries is expected to increase 673 percent by 2030, and there may not be enough orthopedic surgeons to perform these surgeries.9 This dramatic increase is because of the aging population and prevalence of overweight and obese Americans. Such a demand for surgeries and for orthopedic surgeons would inevitably burden the current health care system and patients would have to wait longer for surgery.
Patients are often told, however, to exhaust every alternative of pain relief therapy before they undergo a total knee replacement. Complications can include infection, nerve damage and, if the prosthesis used to replace the joint loosens, the surgery may need to be performed all over again.8 According to the AAOS, joint replacement is still one of the most successful procedures conducted by orthopedic surgeons today and, if a patient commits to the surgery, outcome studies have shown an immediate and dramatic benefit to the patient. The average age of those getting total knee replacements in 1999 was 69, and the average hospital stay was about 4.5 days. Women are much more likely to have the knee replacement surgery than men, but at a more advanced stage of osteoarthritis than men do.10