A new water setting light plastic plaster material, Crystona, is presented and its plaster room characteristics compared with plaster of Paris. Plaster of Paris is considered better as the "acute fracture splinting material" in the Accident Service setting. Crystona, however, has considerable advantages as the "dynamic bracing material" in the post-acute fracture period and is demonstrated in the functional bracing of femoral shaft fractures. An improved functional cast brace design is presented, the "Knee Hinge Cylinder Brace" with a simple waist belt suspension to a hinged tube cast without the foot in the treatment of distal half femoral fractures. Using Crystona and the cylinder brace design, the cast weight has been reduced by half and the functional limb bracing improved with free mobilization of the knee, ankle and foot. The prescription, application technique and early clinical experiences are presented.