LEAD FOREIGN-BODY ARTHROPATHY IN A HORSE

A diagnosis of degenerative joint disease secondary to an intra-articu lar metallic foreign body in the right metacarpo-phalangeal joint was made in a Quarter Horse gelding. Arthroscopy, performed to evaluate th e joint and remove the foreign body, revealed yellow discoloration of the articular cartilage and synovium, and blunting and proliferation o f the synovium. The foreign body was identified as a lead sphere. Micr oscopic examination of synovium revealed chronic synovitis, with accum ulation of hemosiderin and multifocal, mild mineralization. Another pi gment was evident extracellularly in the synovium. Lead arthropathy wa s diagnosed. Lead arthropathy results from the dissolution of intra-ar ticular lead, causing signs of chronic pain, restricted motion, joint effusion, and synovial proliferation.