The word arthritis literally means inflammation of the joint. Joints can become inflamed for many reasons, including trauma, infection and numerous disease states, but most of us think of arthritis usually as one of two kinds: osteoarthritis or rheumatoid arthritis. These are two very distinct (different) entities, and they are both a huge source of discomfort and disability. A significant amount of new research provides an understanding of both kinds of arthritis so that those who are afflicted may find relief (see our What You Can Do sections for more information).

The prevalence of arthritis and other rheumatic conditions in the United States is very high – currently over 70 million Americans (1 in 3 adults) – and is projected to rise as the population ages. Arthritis is the leading cause of disability among persons over age 15! In the following pages, you will learn about the underlying cause of most forms of joint degeneration and arthritis. The What You Can Do sections will show you how you may be able to reverse these degenerative processes.

The Normal Joint
To understand diseases of the joint, we need to look at the normal healthy joint.

Joints are held together by a joint capsule (green in the diagram above) that is designed to allow smooth movement between adjacent bones. In the type of joint that is most commonly affected by arthritic disease (the highly moveable joints), the bone ends are covered by articular cartilage (purple in the diagram) over which the joint moves. A synovial membrane (light blue in the diagram) encloses the joint space (yellow in the diagram) itself. This thin membrane secretes synovial fluid that lubricates the space between the cartilage-covered, joint-forming bones. The cartilage contains no blood vessels or nerves (this is why it takes so long for joints to heal) and receives its nutrients by diffusion from the synovial fluid and from the bone.

Joint function depends on the health of the cartilage in the joint and the synovial membrane. Cartilage (purple in the diagram) is the gel-like substance that acts as a shock absorber, essential for smooth and easy movement in the joint. Cartilage gets its elasticity from collagen (protein) fibers and its sponge-like quality from water (water comprises ~70% of the joint matrix). Cartilage is held together by a structure of big molecules called proteoglycans. Special cells (called chondrocytes) in the cartilage produce collagen and proteoglycans.

As we age, the ability to restore and maintain a normal cartilage structure decreases. The activity of important repair enzymes is reduced, the water content diminishes, and the joint become prone to damage.

Inflammation – The Underlying Cause of Joint Damage
Inflammation is the natural response of our tissues to stress, whether that stress is mechanical, chemical or immunological in nature. In addition, normal aging often results in the excessive production of autoimmune substances that destroy joint cartilage and other tissues in the body. Suppressing these inflammatory substances is a critical component of an effective joint health and/or arthritis management program.

Rather than get into the exact biochemical mechanisms of joint degeneration, lets suffice it to say that we want to minimize the pro-inflammatory compounds and increase anti-inflammatory compounds while minimizing side effects to elicit optimal joint health.

Inflammation is partially characterized by high levels of arachidonic acid products which are metabolized along two different enzymatic pathways: cyclooxygenase (COX) and lipooxygenase (LOX), leading to PGE-2 and LTB4 (see the diagram below). Ideally, we inhibit inflammation by (1) limiting the amounts of arachidonic acid in the body, (2) disrupting the conversion of arachidonic acid into PGE-2 (through COX-2 inhibition), and (3) disrupting the conversion of arachidonic acid into LTB4 (through LOX inhibition).

It should be clear at this point that one of the major causes of joint damage and degeneration is excessive inflammation in the body. Any therapy that can effectively address and alleviate this inflammation will help protect the joints; nutritional therapies can also be used to repair the damage that has already been done and minimize future degeneration.

Current Medical Treatment
The conventional treatment for both osteoarthritis (OA) and rheumatoid arthritis (RA) has consisted of non-steroidal anti-inflammatory drugs (NSAIDs), including aspirin, ibuprofen, and naproxen. Even stronger disease-modifying drugs such as corticosteroids, gold salts and methotrexate are often prescribed for RA in an aggressive attempt to stop the development of the disease. New drugs aimed only at COX-2 inhibition are also used, including Vioxx and Celebrex.

These drugs are all aimed at alleviating pain and reducing inflammation and they can sometimes be effective. However, more often they prove unsatisfactory and many times intolerable due to toxicity and serious side effects. Once more, these treatments are only symptomatic and do not stop the progression of the disease. In fact, the opposite has shown to be true – it has been demonstrated in some studies that NSAIDs actually inhibit the repair of cartilage and accelerate cartilage destruction.

Osteoarthritis
Osteoarthritis (OA) is a disease mainly characterized by degeneration of the articular cartilage (purple in the diagram) but these changes also involve the synovial membrane (light blue in the diagram) and the bone next to the cartilage. It is a gradual decay that most often affects the weight-bearing joints (knees, hips and spinal joints) and the joints of the hand.

A breakdown of the cartilage matrix leads to cracks and ulcers and a thinning of the cartilage with a loss of hock absorption. The underlying bone starts to thicken as a response to the increasing stress, and bone spurs are formed. In the advanced phases of OA, an inflammatory reaction in the synovial membrane can be seen.

This severe degeneration causes pain, swelling, deformation, and reduced range of motion. Because the joints of the hand and the large joints of the spine, hips, knees and ankles are frequently involved, disability is often significant.

OA comes with the normal processes of aging and affects approximately 70-80% of the population over age 50. The onset is marked by stiffness, crackling joints and pain. As it worsens, more pain and disability occur causing an enormous consumption of painkillers and anti-inflammatory drugs that many times have undesirable long-term effects.

The Signs or Stages of Osteoarthritis

1. Joint stiffness or immobility. OA is often characterized by stiffness in and around a joint. This stiffness is often worse first thing in the morning or following some form of exertion.


2. Pain. Often a dull, aching is experienced in or around the joint. Affected joints may hurt while at rest or during and following activity. These symptoms are generally considered to be the result of localized inflammation.


3. Joint structural changes. As the OA becomes more advanced, inflammation of the lining of the joint cavity may results in enlargement of the affected joint. Bony overgrowth can develop along a joint’s margin while the cartilage within the joint deteriorates and eventually collapses or erodes away.


4. Muscle shrinkage or atrophy. Often the pain experienced in the joints causes the person to cease exercise or activity of the joint. This lack of exercise can result in muscle shrinkage. This may also result from the bony overgrowth or deterioration of the joint and the subsequent decrease in the range of motion of the joint.

The following tables illustrate the differences between OA and RA.

Joints Affected by Osteoarthritis and Rheumatoid Arthritis

Comparison of Symptoms of Osteoarthritis and Rheumatoid Arthritis

Rheumatoid Arthritis
Rheumatoid arthritis (RA) is considered an autoimmune disease, characterized by chronic inflammation and thickening of the synovial lining (light blue in the diagram) in addition to cartilage (purple in the drawing) destruction. In autoimmune disorders, the immune system attacks body tissues as if they were foreign invaders. The progression of RA is a direct result of chronic inflammation. Contributing factors include food allergies, leaky gut syndrome, hereditary factors and infections.

Click here to learn more about the causes of RA.

The following tables illustrate the differences between OA and RA.

Joints Affected by Osteoarthritis and Rheumatoid Arthritis

Comparison of Symptoms of Osteoarthritis and Rheumatoid Arthritis