Which joints are typically involved in Osteoarthritis?

• A. Elbow and shoulder only
• B. 1st CMC, DIP with Heberden's nodes, PIP with Bouchard's nodes, knee, hips, lumbar spine
• C. MCP joints only
• D. TMJ involvement only

Answer: (B)

Osteoarthritis shows a pattern of joint involvement that reflects wear and mechanical stress: it most often affects joints that bear weight or are heavily used in daily hand movements. The thumb base (first carpometacarpal joint) is a common early site because of pinch and grip mechanics. In the fingers, the distal interphalangeal joints frequently develop osteophytes that form visible enlargements known as Heberden's nodes, while the proximal interphalangeal joints can show Bouchard's nodes from similar bony changes. Weight-bearing joints such as the knee and hip are classic targets due to cartilage wear and osteophyte formation. The lumbar spine is also commonly affected by degenerative changes in the facet joints and discs, contributing to back stiffness.

This combination of joints—first CMC, DIP with Heberden's nodes, PIP with Bouchard's nodes, knee, hip, and lumbar spine—best captures the typical OA pattern. By contrast, involvement limited to elbow or shoulder, or isolated MCP joints or TMJ alone, is not the characteristic distribution of OA and would prompt consideration of other conditions or different patterns of disease.