Intra-articular chondroid metaplasia is a rare disease; especially in the first metacarpophalangeal (MCP) joint after surgery. In this report, we present a chondroid metaplasia in the left first MCP joint as a soft tissue mass following the repair of the radial collateral ligament and ulnar collateral ligament. A hypointense signal on T2-weighted images and isointense signal on T1-weighted images without enhancement on MR and accompanied adjacent bone erosion were observed.