External synovial fistula of the knee joint and its treatment with free radial artery fasciocutaneous flap

External synovial fistula of the knee joint is a rare entity. A case is rep orted in which the fistula presented 12 years after the original injury. Th e nature of injury and previous surgery precluded the use of a local flap. Treatment was successful using a foe fasciocutaneous flap. Exposure of vita l structures and metal work are the common indications for flap cover in th e lower extremity. However synovial fistula is another instance where flap cover may be required. This case report emphasises the possibility of delay ed presentation of a synovial fistula and the need for prompt closure, sinc e it can be a path for retrograde infection.