Fabrication Notes of an A.F.O.
by Jeff VanSickle, R.T.O.
Working with A.F.O.'s - Oklahoma Joints
- Select proper size joints to be used. Size should be indicated by outline of joint on medial and lateral of positive mold, or specified on work order. Sizes available are extra large, large, medium and pediatric. Also, heavy duty extra large, large, medium and pediatric.
- Mix up a small amount of plaster and secure joints in place as indicated on cast. Position the joints parallel to one another and 90 degrees to the foot base line. Note: see fig. A - incorrect position and fig. B - correct position. Secure mold in vice. Heat one joint in 350 degree oven approximately 3-6 minutes until flexible. With oven gloves, hold joint in place and cool with pressurized air from air hose. Repeat procedure for the other side of foot. Do not try to do both joints at the same time. Overheating may occur on second joint while cooling first joint.
- Clean outer surface of joints with paper towel and clean out the screw holes of plaster. Inspect the cast to see if there are any places that need filling (holes or cracks) while you have plaster.
- Run a piece of sisal rope down anterior for vacuum. Place two nyserts or nylon socks over cast and staple down any loose areas (usually around ankles). Spray lightly with silicone.
- Cut out two small rectangles of plastic for reinforcements at the anterior ankle (see fig. C). Trip and buff as shown (see fig. D). You will use the best looking after heating.
- Cut and clean plastic to pull AFO. Heat at ___. When 2/3 of the way heated, put in the small reinforcing tabs so they will be ready about the same time as the large piece.
- Place best tab in place as marked on mold (tab must bi-sect lower holes of ankle joints) and vacuum form the rest of the AFO over it.
- Drill holes for screws using the sized suggested to the directions.
- Make a cut on posterior bisecting reinforcement using a hand held coping saw (see fig. E).
- Copy trims into the plastic AFO section.
- Cut outside trims onto the plastic AFO section. Remove plastic Oklahoma joints and continue cut started on posterior with coping saw, leaving a foot and calf section as shown in fig. F.