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 proximal interphalangeal joints in a patient with rheumatoid arthritis of the hands.
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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Soft-tissue swelling and early erosions in the proximal interphalangeal joints in a patient with rheumatoid arthritis of the hands.
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Prominent juxta-articular osteopenia in all interphalangeal joints in a patient with rheumatoid arthritis of the hands.
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Well-defined bony erosions in the carpal bones and metacarpal bases in a patient with rheumatoid arthritis of the hands.
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Multiple erosions with deformity of the carpal bones in a patient with rheumatoid arthritis of the hands.
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Follow-up radiograph obtained after an 18-month interval in a patient with rheumatoid arthritis of the hands. Ankylosis of the carpal bones has occurred, with enlargement of the erosions.
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Subluxation in the metacarpophalangeal joints, with ulnar deviation, in a patient with rheumatoid arthritis of the hands.
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Subluxation at the third metacarpophalangeal joint and marginal erosions at the heads of the second to fourth metacarpals in a patient with rheumatoid arthritis of the hands.
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Marked ankylosis of most of the carpal bones in a patient with rheumatoid arthritis of the hands.
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Partial collapse of fused carpal bones with subluxation at the radiocarpal joint in a patient with rheumatoid arthritis of the hands.
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Coronal fine-section gradient echo MR image demonstrates multiple erosions in the carpal bones and bases of the metacarpals, with pannus formation around the distal ulna.
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Axial proton-density weighted MR image at the level of the radio-carpal joint shows extensive tenosynovitis involving the dorsal extensor and volar flexor tendons, with fluid in the tendon sheaths.
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Axial T2-weighted fat-suppresed MR image at the level of the carpal bones shows diffuse synovial hypertrophy over the dorsal aspect (arrows), with a heterogenous appearance and adjacent fluid. Fluid is also present in the dorsal extensor tendon sheaths.
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Axial T1-weighted MR image of the wrist before and after gadolinium administration shows diffuse contrast enhancement in the areas of synovial hypertrophy and thickening, over both the dorsal and volar aspects.
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Illustration of the scanning technique. Photograph depicts the typical scanning technique with application of the Entos Probe to the volar (flexor) aspect of the third metacarpophalangeal joint. The technique allows visualization of the joint surfaces, flexor tendon, and synovial sheaths in patients with rheumatoid arthritis.
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Amplitude color Doppler sonogram in a patient with active rheumatoid arthritis. Dorsal (extensor) surface of the second metacarpophalangeal joint is imaged. Intense-amplitude Doppler color flow signal demarcates the inflamed synovium (ie, joint pannus) resulting from severe hyperemia. Solid arrows indicate the extensor tendon sheath and dorsal and volar margins. Straight open arrow indicates the synovium of the joint overlying the proximal phalanx of the second digit. Curved open arrow indicates the inflamed synovium overlying the metacarpal. The asterisk indicates a small amount of anechoic fluid in the joint space.
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Power Doppler image shows hyperemic blood flow in the flexor tendon sheath in a patient with rheumatoid arthritis of the hands.
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Ultrasonography-guided synovial biopsy of the second metacarpophalangeal joint of the right hand in a patient with rheumatoid arthritis of the hands. The biopsy needle is seen as a straight echogenic line on the left side of the image in an oblique orientation.
