Presentation
Pain and swelling in both hands.
Patient Data
Both hands-Typical findings of rheumatoid arthritis are seen in this oblique projection of both hands. Bilateral and symmetric, destructive, erosive arthritis affecting multiple joints of both hands, carpus and wrists. The affected joints show marginal and central articular erosions with soft tissue swelling and peri-articular osteopenia. Concentric joint space loss with subchondral cysts. Multiple deformities at the affected joints, including ulnar deviation at the MCP joints.
X-ray of right hand in this advanced case, shows involvement of wrist, radio-ulnar, carpal, CMP joints. Pannus commonly destroys ulnar styloid, as in this case. Note uniform loss of joint space, in contrast to asymmetric loss in osteoarthritis. Note typical joint deformities eg Boutonniere deformity at the thumb (see discussion).
X-ray of left hand- Note 'swan-neck' deformity at little and index finger. This is seen as hyper-extended PIP and flexed DIP and MCP joints (see discussion).
Case Discussion
Rheumatoid arthritis is a chronic, auto-immune, inflammatory disorder affecting multiple organs, It most affects synovial joints, commonly the hands and feet. In the hand, it is seen as an inflammatory arthritis with characteristic bilateral, symmetric, multi-articular involvement.
The inflammation initially is seen on X-ray as soft tissue swelling around affected joints. This progresses pathologically to formation of destructive synovial pannus, leading to marginal erosions seen on radiographs. As the disease progresses, central erosions and concentric joint space loss due to cartilage loss, are also seen. Articular surface breach with subchondral cysts may be seen.
Inflammatory pannus causes some typical deformities and subluxation at the destroyed articular surfaces.
Swan-neck deformity is initiated by a flexor synovitis that increases the flexor pull on the metacarpophalangeal joint. PIP hyperextension may be due to lax volar plate, tethered collateral ligaments and/or flexor tendon rupture. Flexion at the DIP may be reciprocal or due to extensor tendon inflammation.
Boutonniere deformities occur when the central slip of the extensor digitorum tendon is torn or stretched resulting in PIP joint flexion. Increasing PIP joint flexion causes further extensor retinaculum damage resulting in "buttonholing" of the proximal phalanx between the lateral bands of the extensor tendon. Secondary DIP joint extension then occurs,
Note: Grateful acknowledgement of images and case kindly contributed by my colleague at Chesterfield, Dr Ian Bickle.
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