What is arthritis?
Arthritis is damage to the articular cartilage. Articular cartilage is very specialised slippery white tissue that covers the ends of the bones at the joints. It is required for near frictionless movement and shock absorption which are essential properties of synovial joints.

Osteoarthritis
Also called degenerative joint disease, this is the most common type of arthritis, which occurs most often in older people. This process affects cartilage, the tissue that cushions and protects the ends of bones in a joint. With osteoarthritis, the cartilage starts to wear away over time. In extreme cases, the cartilage can completely wear away, leaving nothing to protect the bones in a joint, causing bone-on-bone contact. The bones may expand and form osteophytes (bony spurs) around the edges of the joint. In time the joint may deform, causing stiffness and angulation in the limb.
Osteoarthritis causes joint pain and can limit a person’s motion ability to freely move and bend a joint.. When severe, the joint may lose all movement, causing a person to become disabled. Mobility can be severely affected by knee arthritis.

Rheumatoid arthritis
This is an autoimmune disease in which the body’s immune system attacks healthy joints, tissues, and organs. This disease inflames the lining (or synovium) of joints. It can cause pain, stiffness, swelling, and loss of function in joints. When severe, rheumatoid arthritis can deform, or change, a joint. For example, the joints in a person’s finger can become deformed, causing the finger to bend or curve.
Rheumatoid arthritis affects mostly joints of the hands and feet and tends to be symmetrical. This means the disease affects the same joints on both sides of the body (like both hands or both feet) at the same time and with the same symptoms. No other form of arthritis is symmetrical. About two to three times as many women as men have this disease.

Causes of knee osteoarthritis
Osteoarthritis is caused by the wearing out of the cartilage covering the bone ends in a joint. This may be due to excessive strain over prolonged periods of time, or due to other joint diseases, injuries or deformities.
Primary osteoarthritis is commonly associated with aging and general degeneration of joints.
Secondary osteoarthritis is generally the consequence of another disease or condition, such as repeated trauma to the affected joint, or abnormal joint structures from birth.
Uric acid crystal build-up is the cause of gout and long-term crystal build-up in the joints may cause secondary osteoarthritis and deformity.
Some people may have congenital and developmental abnormalities of the joints-for example, Perthes’ disease of the hips-that causes early degeneration and subsequent osteoarthritis
Abnormalities of knee joint function resulting from fractures of the knee, torn cartilage, torn menisci and torn ligaments can lead to degeneration many years after the injury. The mechanical abnormality leads to excessive wear and tear and eventually, osteoarthritis.

 Symptoms of knee osteoarthritis?

• Pain
• Tenderness
• Swelling
• Limitation of motion of
• Early morning stiffness

The main symptoms of osteoarthritis are pain, stiffness, and loss of function. Pain tends to increase with activity.
Joint inflammation may also cause warmth, redness, and swelling.
Inflammatory arthritis may cause early morning stiffness and skin rashes.

Diagnosis
Osteoarthritis is diagnosed by the medical history, physical examination of the joint, and with X-Rays and MRI scans.
Inflammatory arthritis may also require blood tests and occasionally, tissue biopsy.

Treatment

• Initial treatment for osteoarthritis of the knee is conservative.
• Weight control to reduce the stress on the joint and the use of analgesic and or anti-inflammatory medications to control the pain
• For more severe symptoms, an injection of a lubricating fluid (Hyaluronic acid) into the joint can be quite helpful.

Exercises to keep joints flexible and improve the strength of hamstring and quadriceps muscles. Studies have shown that exercise helps people with arthritis by reducing joint pain and stiffness and increasing flexibility, muscle strength, and energy. It also helps with weight reduction and offers an improved sense of well-being.
When conservative measures have been exhausted and are no longer helpful, and arthritis has become disabling, surgery may be recommended in the form of total knee replacement or partial total knee replacement.