Arthritis is a degenerative process that can affect literally any joint in the human body. It slowly robs the joints of their protective, smooth cartilage surfaces which are responsible for fluid motion of the opposing bones. Arthritis can start out as a mild ache or soreness and can progress to a painful, activity-limiting problem. Arthritis can be caused by several factors; each with its own unique aspects. Regardless of the cause, the resulting arthritis causes pain, mobility restrictions and can severely alter a person's lifestyle.
Osteoarthritis
Osteoarthritis is widely considered to be the most common form of degenerative joint disease today. According to the Centers for Disease Control (CDC), an estimated 46 million people in the U.S. alone reported being told by their health care providers that they have some form of arthritis.
Osteoarthritis is known as the "garden variety" arthritis, mainly because it is so prevalent and is caused by general wear and tear of the joints, especially the weight-bearing joints of the lower extremities--the knees, hips and ankles. That being said, osteoarthritis can strike any joint in the body. Osteoarthritis involves the gradual degeneration of the highly specialized, plush cartilage surfaces of the joints, called hyaline cartilage.
Think of the joint surface as tread on a tire. It has a specific thickness to it and over time, begins to wear down. This wear doesn't always occur in a uniform manner, which causes irregularities in the joint surfaces. This, in turn, causes friction which leads to pain and swelling
Rheumatoid Arthritis
Rheumatoid arthritis is a destructive, ravaging disease of the joints. It is more specifically a disease of the joint lining, called the synovium. Rheumatoid arthritis, RA for short, has a very strong hereditary component and usually affects people in their 40s to 60s.
In the case of RA, the synovial lining of the joints becomes abnormally inflamed and swollen, so much so that the tissue of the synovium can begin to migrate and literally invade the joint cartilage from its outer margins inward.
Rheumatoid arthritis is also known as an autoimmune disease, in which case the body literally attacks itself. In chronic and severe cases, organ systems such as the lungs can also be affected. People with RA often will develop small bumps under the skin, called rheumatoid nodules. These nodules are a unique characteristic of rheumatoid arthritis.
Post-Traumatic Arthritis
As the name implies, this type of arthritis is typically caused by some kind of trauma that results in injury to a joint. Any joint can be subject to traumatic injuries, and not all injuries will develop arthritic changes.
Some of the more common mechanisms of injury that can result in the development of post-traumatic arthritis can include motor vehicle accidents with dashboard injuries to the knees, traumatic hip joint dislocations, severe intra-articular (which means "into the joint") ankle fractures and fractures of the wrist. Penetrating trauma to a joint, such as gunshot injuries, can also lead to arthritis formation.
In cases of trauma, the joint surface cartilage is abruptly damaged as well as the underlying bone. When fractures extend into the joint, they can cause surface irregularities very similar to what happens to streets and land from an earthquake. These irregularities, if not repaired satisfactorily, will cause significant friction and abnormal wear, which leads to inflammation and degeneration of the surfaces.
Septic Arthritis
Septic arthritis is joint surface degeneration caused by infection. Infection in a joint is a very serious matter, which needs urgent treatment. This type of arthritis is occasionally seen in small children and older adults. It tends to only affect one joint. In children, the most frequently affected joint is the hip.
Septic arthritis typically involves the introduction of bacteria into a joint. This is accomplished by several means such as: direct introduction from a penetrating type of injury; infection elsewhere in the body in which case the bacteria can be seeded, or introduced, into the joint from these remote areas; and through artificial joint replacements.
Bacteria in a joint grow and proliferate as the infection worsens. They can produce an exudate, or eternal fluid, called pus. As the volume of pus increases, it begins to increase pressure within the joint. Pus under pressure is extremely dangerous and destructive to the joint.
Gout
Gout is a systemic condition, often inherited, that involves the presence of abnormal amounts of a substance in the bloodstream called uric acid. Although uric acid, a crystalline substance, is produced naturally in the body and is responsible for aiding in the breakdown of a substance called purines, a person with gout is cursed with either an over-production or an under-excretion, or removal, of it.
In either case, there can occur occasions where the concentration of uric acid crystals in the circulation becomes abnormally high. These crystals can then leach out into joints and become deposits on the joint surface cartilage and on the synovial lining of the joint. These deposits create significant inflammation and severe pain. Uric acid crystals also increase a person's risk of developing kidney stones.
