Knee Osteoarthritis, the most common type of osteoarthritis, is a chronic degeneration of the articular cartilage around a joint.
Knee osteoarthritis most commonly affects people over 45 years of age but can occur at any time.
When knee osteoarthritis develops, the cartilage undergoes gradual changes – loosing elasticity, hardening, and cracking, becoming more easily damaged and eroded by use or injury.
The bones can’t move smoothly over roughened cartilage, causing irritation to the bone. The end of the bones involved may thicken and bone spurs may form. Small bits of cartilage may break off and float around inside the knee. Over half of knee osteoarthritis sufferers also have mineral deposits in their cartilage. The joint fluid also changes in consistency, becoming thinner and less tacky, decreasing its lubricating and cushioning properties.
There are many different levels of severity of damage, from mild cases without symptoms or with mild symptoms to advanced cases where the cartilage is worn down to the point where bone rubs on bone, damaging the bones and causing severe knee pain.
Though osteoarthritis is considered to be non-inflammatory type of arthritis, minor inflammation is involved. The inflammation is not nearly as severe as the inflammation involved in inflammatory types of arthritis such as rheumatoid arthritis.
Knee osteoarthritis used to be considered a ‘wear and tear’ disease because it mainly affects middle-aged and elderly people and worsens over time. However, normal activity does not cause knee osteoarthritis, and the cause of cartilage deteriorating and wearing away is not known. Enzymes that damage the joint cartilage have been identified. Doxycycline, an antibiotic that has been shown to inhibit these enzymes, was shown to slow down cartilage deterioration in study led by Indiana University School Of Medicine’s arthritis and muscles diseases center. Cod liver oil has also been shown to inhibit these enzymes.
Many people reduce their activity because of knee pain or because they believe it will worsen knee osteoarthritis. As a result, the muscles that support the knee become weaker and more stress is placed on the knee joint.
SYMPTOMS OF Knee Osteoarthritis
The deterioration of cartilage is gradual and there may be no symptoms in the early stages of knee osteoarthritis. Symptoms of knee osteoarthritis are stiffness (especially morning knee stiffness), knee pain that is aggravated by going up or down stairs, limitation in range of motion, a crunching feeling in the knee, and weakness of knee. The knee may be swollen but not red and hot.
(Symptoms such as diffuse pain in knee joint and crunching sound in the knee can be caused by “runners knee”, which is a common cause of knee pain in all age groups, including teens and young adults.
Swelling of the knee may occur as a result of excess fluid accumulating within the knee joint. Damaged cartilage in the joint triggers inflammation of the joint lining (the synovium) and excess production of joint fluid (synovial fluid).
An accumulation of excess fluid within a joint is called joint effusion. In the knee, joint effusion is sometimes referred to as water on the knee. Knee joint effusion sometimes results in a Baker’s cyst.
In advanced cases, inflammation can also occur if bits of cartilage break off and float around inside the knee joint and cause irritation and inflammation of the soft tissue in the joint.
In advanced cases, there may be deformity of the joint. Cartilage has a limited ability to repair itself. The body compensates with the growth of extra bone, which results in visible enlargement of the joint.
Symptoms do not always correlate with the amount of damage to the joint. Symptoms can come and go for no apparent reason. This makes it difficult to assess whether or not a current treatment is working. Keeping the muscles that support the knee strong, keeping your weight down, and avoiding high impact activities can decrease the symptoms.
FACTORS increasing the risk of Knee Osteoarthritis
Muscle weakness in the quadriceps (muscles of the thigh that attach to the knee)
Injury to the joint
Repetitive movements (squatting, kneeling with heavy lifting)
Activities requiring repetitive joint impact – jogging
TREATMENTS for Knee Osteoarthritis
Exercise is beneficial for knee osteoarthritis: Strong leg muscles support the knee and absorb shock before it gets to the knee. Exercising the quad muscles increase circulation in the knee joint and has been shown to stimulate beneficial biochemical changes in the joint fluid of the knee, improving its lubricating properties. Exercise also improves the range of motion of the knee. However, in patients with knee osteoarthritis who have misaligned knees, over-strengthening of the quads can sometimes make matters worse. A doctor or physical therapist (physiotherapist) can determine whether or not your knees are properly aligned and which exercises would be most beneficial.
Heat and Cold:
Applying heat to the knee joint reduces stiffness and pain by increasing blood flow. The heat is also a comforting distraction from the knee pain. DO NOT apply heat to an inflamed joint. Usually, inflammation is not present in the early stages of knee osteoarthritis.
Apply heat for 20 – 30 minutes at a time, waiting at least an hour between each application to prevent overheating of tissues. Dry or moist heat is beneficial but moist heat penetrates the tissues more quickly, and penetrates more deeply than dry.
For moist heat, you can use a towel soaked in warm water but it may cool off fairly quickly. An alternative is to place a moistened towel between your knee and a hot water bottle. There are also moist heating wraps available commercially.
*Do not use rubs and heat at the same time as a burn may occur.
Cold reduces knee inflammation and knee pain by constricting the blood vessels. Apply ice wrapped in cloth to an inflamed joint for 15 – 20 minutes every 3 or 4 hours. Do not ice for longer than 20 minutes at one time to avoid frostbite. Moist cold (Place a wet towel between the skin and an ice pack for moist cold) penetrates more deeply and quickly than dry cold.
Being overweight places extra stress on the knee, a weight-bearing joint. Even 10 pounds can make a big difference in the symptoms of knee osteoarthritis.
Though the reason it works is unclear, knee taping has been shown to significantly reduce knee pain in patients with knee osteoarthritis. There are different taping techniques that a physical therapist (physiotherapist) can teach a patient. Sometimes the skin can become irritated from the tape.
Used For Certain Cases of Knee Osteoarthritis: Unloader braces are designed to provide knee pain relief for those with knee osteoarthritis. They are very expensive but some health insurance plans cover them. Quite frequently, the cartilage is more worn out of one side of the knee joint, causing the thighbone to sit on an angle and the thighbone to rub against the shinbone on the worn out side. Unloader braces take off the load (pressure) on a knee joint by changing the angle of the knee joint. By changing the angle of the knee joint, a space between the thighbone and shinbone is created, relieving knee pain and increasing range of motion. An x-ray can determine if the space between the thighbone and shinbone is angled. A doctor or physical therapist (physiotherapist) can assess whether or not an unloaders knee brace would be helpful in a particular case and recommend the appropriate knee brace.
This therapy involves stimulating nerve endings with low voltage electric impulses through electrodes attached to the body at the site of the pain. It relieves pain in some patients