Surgical fixation of closed ankle fracture is traditionally viewed as having low risk for post-operative infection. Only a few cases of surgical-site confined infection have been reported. Because of the low infection risk, the necessity for perioperative prophylaxis has been questioned. We report a case of fulminant methicillin-resistant Staphylococcus aureus endocarditis occurring shortly after an elective ankle fixation surgery in an elderly woman with chronic rheumatoid arthritis. Because systemic infection was unexpected, she had been given antipyretics for postoperative fever until just before rapid clinical deterioration. A nearly fatal hematogenous infection occurred after such a procedure, indicating the necessity for being on high alert and considering the possibility of bloodstream infection.