Rheumatoid Arthritis Hand Deformities: Clinical Description and Features

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disorder primarily targeting synovial joints. In advanced or inadequately controlled disease, characteristic hand deformities frequently develop—particularly involving the fingers—and serve both as clinical markers of disease progression and functional impairment.

Common finger deformities in RA include ulnar deviation, where the fingers drift radially at the metacarpophalangeal (MCP) joints due to chronic synovitis, ligamentous laxity, and tendon imbalance. Swan-neck deformity—characterized by hyperextension of the proximal interphalangeal (PIP) joint with concurrent flexion of the distal interphalangeal (DIP) and MCP joints—arises from extensor tendon dysfunction and volar plate attenuation. Boutonnière deformity presents as PIP joint flexion with DIP joint hyperextension, typically resulting from central slip rupture or attenuation of the extensor mechanism.

Other structural changes include Z-thumb deformity (hyperextension of the interphalangeal joint with flexion of the MCP joint), hitchhiker’s thumb (hyperextension of the MCP joint and flexion of the interphalangeal joint), and subluxation or complete dislocation of the MCP joints. These deformities reflect cumulative damage from persistent synovial inflammation, cartilage erosion, bone remodeling, and periarticular soft-tissue compromise.

Early diagnosis, aggressive disease-modifying antirheumatic drug (DMARD) therapy—including conventional synthetic, biologic, and targeted synthetic agents—and timely referral to rheumatology and hand therapy are critical to preserving joint integrity and preventing irreversible structural change. Surgical intervention, such as tendon realignment or joint arthroplasty, may be indicated in select cases with severe functional limitation.