Carpal Hygroma in Horses

A carpal hygroma is a subcutaneous swelling over the cranial/dorsal aspect of the carpus. Typically, a history of trauma to the carpus is noted. The swelling is typically aseptic, but risk of infection can develop after drainage or injection. Typically, a hygroma is a cosmetic blemish, and lameness is not usually present. The diagnosis is made by palpation and visualization. Injection of contrast material into the hygroma and subsequent radiographic examination outlines the extent of the hygroma. Communication between joint and hygroma is confirmed or excluded through fluid injection into the carpal joints. Hygromas can be treated in the early stage with drainage, steroid injections, and bandaging. When infection is present, surgical resection of the infected tissue is recommended.