A multi-phase orthopedic system including a moisture-impervious sleeve, a moldable splint including a covered resin-impregnated substrate, an elongate removable wrap for retaining the splint on the limb, and a removable cast for application to the limb during a subsequent treatment phase including a cast body having an interior side and exterior side, and a flap carried by the body and movable between an open position, and a closed position overlying a part of the cast body to be applied to a treatment area of the limb, the flap adapted to cover and retain between the cast body and the flap the splint worn by the patient during the initial treatment phase in the same position as the location of the splint during the initial treatment phase. A method of immobilizing a limb in multiple treatment phases utilizing the multi-phase orthopedic system.