A Stress fracture of tibial malleolus is rare and only seven cases were reported in the literature. Recently, we encountered a patient who was a seventeen years old boy and had been playing rugby-football. He had a history of pain around his left tibial malleolus for a month, however, he had continued playing rugby. On examination, slight swelling and tenderness were found over the tibial malleolus and pes planovalgus and genu varum were also noticed bilaterally. Radiographs demonstrated oblique fracture line in the left tibial malleolus suggesting the stress fracture and he was kept away from playing rugby for a month. Subsequently, pain was relieved and radiographs showed the sign of recovery. He returned to sports activity without difficulty. In this case, slight deformities of his legs (pes plano-valgus and genu varum) and his role in rugby as right flanker, are considered to cause the stress fracture of the tibial malleolus.
