The garden-variety arthritis that afflicts millions of people is the great humbler – the nagging messenger that tells the truth about age. Joints are the junctions between bones that allow movement of the skeleton. Over time joints suffer from wear, tear and imperfect repair and the result is “osteo(bone)arthr(joint)itis(inflammation).”
The structure of joints: cartilage, synovial membranes, tendons and ligaments
You have 206 bones and over 230 joints. The more movement required at a junction between bones, the more complex the joint. In freely moveable joints the ends of the bones are covered with cartilage, a smooth, tough and pliable tissue that lacks a blood supply. In some joints there are also cushions of cartilage – menisci or discs – between the bones. Cartilage is the weak link in joints – the part that thins out and breaks down with age. Bone stripped of cartilage slides poorly and painfully over other bone. Old, dried out discs and menisci fragment and hurt. Inflammation and more pain accompany the body’s attempts to repair the damage.
The synovial membranes lining joints make a thick, lubricating fluid that seeps into crevasses in cartilage, where it forms reservoir pools that keep the thin film of fluid between the bones even during movement. This synovial fluid carries nutrients and waste products and depends on joint movement for its circulation.
The ligaments that connect bone to bone, and the tendons that attach the muscles to bone form the joint capsule. Tendons and ligaments are tough and gristly and have poor blood supplies. They heal slowly, repairing themselves with stiff scar tissue. Time marks its progress in these structures by making them less flexible and more prone to damage.
The pain of joint inflammation, the stiffness of ligaments and tendons, and the resulting limitation of joint movement are the cardinal symptoms of osteoarthritis. Excessive bone formation, narrowing of joint spaces and irregularity of bony margins, seen mainly on X-rays are signs of the ailment. In contrast to other more inflammatory joint problems, such as rheumatoid arthritis and gout, osteoarthritis produces no blood or joint fluid abnormalities.
Why are some people more affected than others by osteoarthritis?
If osteoarthritis is a result of age, then why are some people crippled at 60 and others still dancing at 90? As usual, genetic makeup counts. Some families pass arthritis down. Others pass along bowed legs and other skeletal builds that result in early joint deterioration. Osteoarthritis also creeps into joints injured long ago and into joints damaged by inflammation from infectious and immune system diseases. Obesity contributes to the load on weight-bearing joints, subjecting them to more damage.
Use joints or lose them: underactivity ages joints
While overuse at times predisposes joints to arthritis, under use is also a threat. There is ample evidence in laboratory animals that joint immobility produces degeneration. Zookeepers have long known that elephants in captivity, deprived of their need to walk thirty miles a day in search of food, develop debilitating arthritis in their hips and feet. Joint cartilage gets nutrients from the surrounding tissues by diffusion through the joint fluids. Movement helps that diffusion, so optimal joint health depends in part on regular movement through a full range of motion.
Limited joint motion sets up a process of uneven wear that precedes arthritic change. In Eastern cultures, where squatting is frequent, thinning of cartilage in the hip joint occurs with age just as it does in the West, but hip degeneration is far less common. Squatting puts the ball-and-socket joint of the hip through the rotational movement for which it is designed, while walking and sitting in chairs requires flexion and extension in only one plane, wearing cartilage unevenly.
Osteoarthritis develops over many years. There is no cure. Medical treatment focuses on maintaining the mobility that pain and stiffness reduce. Reduced movement causes muscle weakness, tightens tendons and ligaments, and deprives cartilage of synovial fluid circulation. Intervening in this cycle requires relief of pain and maintenance of activity.
Anti-inflammatory agents such as aspirin and ibuprofen are helpful – but often osteoarthritis involves little real inflammation and the potential hazards of chronic use of these medications (kidney damage) have to be weighed against their pain-relieving benefits. Ice, heat, massage and topical agents like Ben Gay are substitutes. Supplements such as glucosamine and chondroitin – the building blocks of cartilage – are thought by some to be helpful. While there is no proof of their efficacy, there is also no indication that they are harmful. External devices such as knee braces and back supports are useful for stability in exercise.
Exercise is treatment
Exercise is crucial for joints. Properly carried out, exercise strengthens muscles and maintains range of motion. Stiffness improves as a joint “warms up.” With time, patience and the proper exercises, range of motion can be increased and symptoms greatly reduced. Exercise promotes weight loss, which relieves the load on hips, knees, ankles and feet. Because it reduces gravitational forces, water is a wonderful medium for exercise for arthritic patients.
Alternative treatments and joint replacement
Acupuncture might help some people. Cortisone injections provide transient relief, but weaken tissues further. Because osteoarthritis is common and often debilitating, patients are easy targets for sales pitches guaranteeing relief. Therapies like magnets and copper bracelets and a host of pain relieving supplements beckon everywhere. At the end of the line for a joint, there is the prospect of replacement. Artificial joints restore mobility and improve life significantly for many arthritis sufferers – but they are to be approached with the care and caution. Joint replacement is a major surgical procedure in which the original joint is permanently removed. The recovery process is arduous and the new joint surfaces are also subject to wear and tear. Time marches on in titanium as well as in bone.
http://www.arthritis.org/default.asp – Arthritis Foundation homepage
http://www.rheumatology.org/public/factsheets/index.asp – American College of Rheumatology – patient education page
http://www.arthritis.com/ – Animated graphic representations of joints and arthritic processes.