CASTING & CAST-FILLING

To begin the creation of an AFO, a negative mold must first be created. To start, one should first put a liner, or some type of lubrication (such as Vaseline), on the patient's leg.  Have the patient take a seat and place their leg at a 90 degree angle, making sure to prop the heal up slightly to imitate the heel raise in shoes.  The patient will assist the clinician by holding a rubber tube along the outer edge of the leg so that the negative model can be removed in the future. Lastly before the wrapping process, make sure to use a specific colored pencil to mark the malleoli and other important landmarks on the person. Then, take the plaster wrap roll and dip it into a bucket of cold water and gently squeeze to remove excess liquid.  Beginning at the top of the calf, wrap around approximately 3 times before descending to the rest of the leg.  With plaster wrap, one should make sure to have about 3/4 overlap of each layer.  Likely, one will use at least one roll of plaster cloth wrap to cover the lower leg/calf region, and another roll to wrap the foot and ankle.  Wrapping the ankle and heel are some of the trickier spots when creating a negative model.  After wrapping is complete, let the plaster set and wait until it is dry.  Make sure to draw some horizontal lines perpendicular to the line you will cut. Once dry, the clinician will use an electric orthopedic cast cutter tool to remove this negative model, specifically cutting along the protrusion caused by the rubber tube.  After cutting this off, one can forcefully remove the cast, and then will staple it back together so that a positive model can then be created.  The positive mold is created by creating a plaster mix, using water and plaster powder, and pouring this mixture into the negative mold of the patient's leg.