MCP subluxation of the thumb on radiography

A frontal view of the left hand (A) shows dorsal subluxation at the first MCP (arrow). Image B is a magnified view showing subluxation with degenerative change that includes joint space narrowing, sclerosis (arrow), and osteophyte formation (arrowhead). Image C is a magnified oblique view that confirms subluxation and degenerative change (arrow).