The word “arthritis” simply means inflamation of the joint. It comes from the Greek words: arthro - meaning “joint”, and itis - meaning “inflamation”.
There are many forms of arthritis but the two main types are osteoarthritis and rheumatiod arthritis. In any event the most common symptom is pain. Osteoarthritis is a form of degenerative joint disease where the internal mechanisms of the joint become worn. This can be caused by wear and tear as we get older, a physical injury to the joint or an infection within the joint. In many cases the arthritic changes can be localised in that only one joint may be affected. Just because someone has osteoarthritis in one joint it does not follow that they will necessarily have arthritic changes in other joints. Rheumatiod arthritis is different in that it is a type of autoimmune disorder where the body’s defense mechanism is over active and the body attacks itself. The changes brought about by rheumatiod arthritis are usually systemic in that the whole body is affected.
So, Arthritis is a general term used to describe an inflammatory or degenerative condition of the tissues associated with the joints. The term most commonly used is degenerative joint disease (DJD) or osteoarthritis and it mostly, although not exclusively, affects older people.
Joints
Anywhere two bones meet is called a joint. The ends of the bones are covered with a highly specialised tissue known as cartilage, which provides an almost frictionless surface that allows the bones to glide smoothly over one another during movement. A group of cells known as chondrocytes are responsible for maintaining and repairing articular cartilage by synthesising proteoglycans, glycosaminoglycans, collagen and other proteins.
The whole joint is contained within a membrane or sac and this whole “joint capsule” contains synovial fluid which is a slippery, oily substance which further lubricates, and supplies vital nutrients to, the cartilage. So, cartilage is slippery and synovial fluid is slippery therefore a normal healthy joint works well and causes no pain. However, with age and/or injury, cartilage can get worn and synovial fluid can lose its quality… the result: pain, stiffness and swelling.
As the cartilage ages, the amount of chondroitin sulphate, the primary glycosaminoglycan found in articular cartilage, produced by the chondrocytes decreases, which compromises the ability of the joints to flex or to bear weight due to structural changes in the cartilage. These changes include thinning of the cartilage which increases the shear stresses near the base of the cartilage leading to deep horizontal splits and progressive cartilage loss. Younger people can also suffer from the effects of arthritis due to excessive compression on the joints,where the cartilage can be squeezed between the relatively hard bone underneath resulting in deformation and even the articular surface sometimes being lifted off.
Apart from the pain, the mobility problems associated with arthritis include a decreased range of motion of the affected joint. For example, arthritis of the knee would produce a shortening of the stride due to decreased knee flexion.
Traditional treatment of DJD is through the use of non-steroidal anti-inflammatory drugs (NSAIDs) and steroidal therapies. However, chronic use of steroidal therapies can cause further degeneration to the cartilage and some NSAIDs can cause stomach problems like ulcers.