What is Rheumatoid Arthritis?

Rheumatoid arthritis involves the synovium of the joints. The condition of rheumatoid arthritis will result in deformities. Rheumatoid arthritis occurs in females more than males.

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There may be a hereditary component with rheumatoid arthritis. Rheumatoid arthritis has spontaneous remissions and exacerbations. The disease can have a systemic nature. Pain and stiffness of joints especially in the morning (morning stiffness). Rheumatoid arthritis is typically poly-articular, bilateral, and symmetrical and most commonly affects the hands and feet.

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X-rays show periarticular erosions at the time of diagnosis. Osteopenia and minimal osteophyte formation favors the diagnosis of rheumatoid arthritis.

Pathogenesis

Rheumatoid is an auto immune disease. The disease has two important components: immunological reactions and increased degradative enzymes. The IgM (rheumatoid factor) is produced by the plasma cell as an antibody to the native IgG, which is altered in RA. 70% of the patients with RA have rheumatoid factor positive. Leukocytes are attracted to the immune complex forming deposits over the inflammatory surface of the synovium. These leukocytes ingest fibrin and immune complex and is called the rheumatoid cells. The leukocytes release lysosomal enzymes that causes acute inflammatory response and tissue necrosis as well as inflammatory mediators (IL-1, IL-6, and TNFα). The chondrocytes respond to stimulation by TNFα, IL-1 and other inflammatory mediators causing cells to become activated and secrete more metalloproteinases which lead to cartilage damage. The synovium becomes hypertrophied (Pannus), showing intimal hyperplasis and infiltration by plasma cells and lymphocytes.

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Stages of Rheumatoid Arthritis

Early stages (acute) include hot, swollen, tender joints (synovitis), wrist swelling, MCP swelling and Flexor Sheath Synovitis. Complicated rheumatoid arthritis include digital vasculitis, ecchymosis, skin atrophy and nodules. Advanced rheumatoid arthritis includes swelling of the MCP joints, lateral slippage of extensor tendons and tendon ruptures and ulnar deviation of fingers. X-rays show destruction of MCP with subluxation, ulnar deviation and wrist destruction.

Finger deformities include mallet, boutonniere, and swan neck.

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The thumb is also involved. These changes occur due to proliferation, inflammation and hypertrophy of the synovium. Involvement of the distal radioulnar joint is usually associated with rupture of the extensor digiti minimi.

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Rheumatoid Nodules

25% of patients with RA will have subcutaneous nodules on extensor surfaces of elbow and forearm. Nodules are often multiple and seen along the ulnar margin of the forearm or pulp of the digits. Vasculitis is more common in patients with SC nodules, it is a strongly seropositive disease (aggressive) with a less than favorable prognosis.

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Treatment

If the patient has synovitis, it should be treated by a splint and medical treatment. If the patient has joint space narrowing, bone erosions and osteopenia the patient will need a synovectomy. If the patient has joint destruction/fixed deformity or loss of hand function, surgery is based on the conditions.

Before operating on RA patients, x-ray of the cervical spine is needed because the patient may have subluxation of C1-C2. Metacarpophalangeal joint arthroplasty of the fingers usually results in decreased extensor lag and improvement of the ulnar drift.

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