Tendinitis and arthritis both result from inflammation of the tissues at joints, causing pain and hampering the ability of the joints to move smoothly and easily. However, they affect different tissues at the joints, result from different factors and have different treatments. Tendinitis refers to inflammation of the tendons, flexible fibrous tissue that links muscles to bones at joints and transmits the force of muscle action to move the joint. Arthritis results from inflammation of the friction-minimizing tissues that line the joints themselves.
Site of Inflammation
The major difference between tendinitis and arthritis is the site of inflammation: the tendons in tendinitis, and the joint lining in arthritis. Although both tendinitis and osteoarthritis become more likely with age and accumulation of wear and tear, tendinitis often results from repetitive motions that over-use a particular tendon causing specific forms of tendinitis such as “tennis elbow” or “jumper’s knee." By contrast, osteoarthritis affects the slippery cartilage between bones at a joint, causing the bones to grind on one another. Other causes of inflamed tendons include infection, diabetes or a thyroid problem. Rheumatoid arthritis occurs when the body’s immune system mistakenly begins to attack and destroy the synovium or smooth inner lining of the joints. The inflammation of arthritis can also spread to tendons, causing tendinitis. But tendinitis cannot cause arthritis.
Nature of Symptoms
The location of pain, extent of the symptoms and long-term consequences of arthritis and tendinitis differ. Tendinitis most commonly affects the shoulders, elbows, hips, wrists, knees and heels. Arthritis can affect the same joints as tendinitis but can also affect other sites such as the spine and fingers. The pain of tendinitis occurs just outside a joint and can radiate up or down the length of the limb. Exercise aggravates the pain of tendinitis, and rest generally relieves it. Arthritis causes pain in the joint itself, as well as stiffness, redness and swelling of the affected joints and decreased range of motion. Unlike tendinitis, arthritis can cause other systemic symptoms such as night sweats, fever, fatigue and rash. Arthritis symptoms usually ease with mild exercise. Although arthritis can eventually twist or deform a joint, tendinitis can lead to a rupture or complete tear of the tendon.
Types of Treatment
To treat arthritis and tendinitis, doctors recommend different exercise regimens, drugs and surgical options. For most cases of tendinitis, home care with an emphasis on resting the joint can effectively treat the problem. Though doctors urge rest for tendinitis, they recommend gentle exercise for patients with arthritis to keep the joints flexible and slow the damage. For tendinitis, a doctor might recommend ultrasound therapy in which sound waves stimulate blood flow to the tendon to speed healing, but this would not benefit arthritis. For arthritis, doctors might recommend skin creams such as capsaicin to ease pain. For people with rheumatoid arthritis, doctors prescribe anti-rheumatic drugs and immunosuppressants. For severe cases of arthritis, a doctor might recommend surgery to remove the joint lining or replace the joint. If you have tendinitis, you don't need surgery unless the tendon ruptures.