Arthritis, Arthroplasty, and Joint Reconstruction
Pattern recognition first
Osteoarthritis. The thumb CMC joint is the most common hand site, staged by Eaton–Littler: I (normal), II (slight narrowing, >2 mm), III (marked narrowing with subluxation), IV (pancarpal with STT involvement). Stages I–II respond to splinting and corticosteroid injection; III–IV are treated with trapeziectomy with or without ligament reconstruction and tendon interposition (LRTI) or suspensionplasty. Scapholunate advanced collapse (SLAC) and scaphoid nonunion advanced collapse (SNAC) follow a predictable sequence (radioscaphoid, then capitolunate, then radiolunate). Four-corner fusion or denervation preserves motion; total wrist fusion is the reliable salvage.
Rheumatoid arthritis. Expect ulnar drift and volar subluxation at the MCP joints and swan-neck deformities. Silicone MCP arthroplasty restores alignment in low-demand patients. DRUJ destruction is managed with Darrach resection or Sauvé–Kapandji. Clear the cervical spine of instability before any RA operation.
Finger joints. PIP silicone arthroplasty is for low-demand, painful joints; fusion is more durable in a young laborer. Thumb MCP arthritis following CMC disease may need fusion or arthroplasty.
Traps: offering arthroplasty to a young high-demand patient; forgetting that Eaton IV includes the STT joint, so trapeziectomy alone may not fully relieve pain; and skipping cervical spine evaluation in RA.
Rule of thumb: Eaton I–II → nonoperative; Eaton III–IV → trapeziectomy with suspension or LRTI.