What is rheumatoid arthritis (RA) and how does it affect the hands?

Updated: Mar 28, 2019
  • Author: Ian Y Y Tsou, MBBS, FRCR; Chief Editor: Felix S Chew, MD, MBA, MEd  more...
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Answer

Answer

Rheumatoid arthritis (RA) is a systemic inflammatory disease that results in cartilage and bone destruction. RA is characterized by a typical pattern and distribution of synovial joint involvement. Disorganization of the joint leads to deformities and loss of function.

In the hands, the metacarpophalangeal (MCP), proximal interphalangeal (PIP), and thumb interphalangeal (IP) joints are most frequently involved. The distal interphalangeal (DIP) joints are involved only in the presence of a coexisting MCP or PIP disease. Tenosynovitis of the flexor tendons causes a reduction in finger flexion and grip strength. Nodular thickening in the tendon sheath may also produce a trigger finger.

In the wrist, the early stages of RA cause tenosynovitis of the extensor tendons, causing swelling over the distal wrist. The ulnar styloid may become tender, which indicates inflammatory synovitis. The distal end of the ulna tends to sublux dorsally, and the carpal bones sublux anteriorly to the distal radius and ulna. Bony erosions and ankylosis of the carpal bones are also seen and appear to be prominent features in Asian patients.

The primary effect of RA is in joint deformity and fusion, which occurs in the advanced stages.

Although occasional flares of joint pain occur throughout the course of the disease, these can usually be controlled with the use of anti-inflammatory medication, especially early in their course. When joint subluxations and deformity take place, performing basic daily tasks (eg, writing and holding utensils) can become a problem. Some patients resort to the use of custom-designed writing instruments or utensils to overcome this difficulty. Permanent disability occurs in approximately 10-20% of patients.

See the images below.

Soft-tissue swelling and early erosions in the pro Soft-tissue swelling and early erosions in the proximal interphalangeal joints in a patient with rheumatoid arthritis of the hands.
Power Doppler image shows hyperemic blood flow in Power Doppler image shows hyperemic blood flow in the flexor tendon sheath in a patient with rheumatoid arthritis of the hands.

See Rheumatoid Arthritis: In and Out of the Joint, a Critical Images slideshow, to help identify the distinguishing features of RA as well as the signs of extra-articular manifestations of this disfiguring disease.


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