An eight-year-old boy, who sustained Salter type II slipping in the distal epiphyseal plate of his left femur, had genu valgum deformity 2 years after the injury. A roentgenogram showed bone bridge at the postero-lateral region of the epiphyseal plate in his left femur. He was operated on to replace the bone bridge by an autograft of the costal cartilage from his right 5th and 7th ribs. Improvement in his genu valgum deformity was revealed within two years after the operation.In conclusion, this procedure of the replacement of bone bridge by the costal cartilage, has beneficial effect to prevent recurrence of bone bridge in the epiphyseal cartilage, and to correct the deformity activating the mechanism of repair of the epiphyseal plate.