The ICRC's "Manufacturing Guidelines" are designed to provide the information necessary for production of high-quality assistive devices. The main aims of these informative manuals are as follows: - To promote and enhance standardization of ICRC polypropylene technology; - To provide support for training in the use of this technology; - To promote good practice. This is another step forward in the effort to ensure that patients have access to high-quality services.# Table of contents

# Foreword
The ICRC polypropylene technology Since its inception in 1979, the ICRC's Physical Rehabilitation Programme has promoted the use of technology that is appropriate to the specific contexts in which the organization operates, i.e., countries affected by war and low-income or developing countries.
The technology must also be tailored to meet the needs of the physically disabled in the countries concerned.
The technology adopted must therefore be:
- durable, comfortable, easy for patients to use and maintain; - easy for technicians to learn, use and repair;
- standardized but compatible with the climate in different regions of the world; - low-cost but modern and consistent with internationally accepted standards; - easily available.
The choice of technology is of great importance for promoting sustainable physical rehabilitation services.
For all these reasons, the ICRC preferred to develop its own technique instead of buying ready-made orthopaedic components, which are generally too expensive and unsuited to the contexts in which the organization works. The cost of the materials used in ICRC prosthetic and orthotic devices is lower than that of the materials used in appliances assembled from commercial ready-made components.
When the ICRC launched its physical rehabilitation programmes back in 1979, locally available materials such as wood, leather and metal were used, and orthopaedic components were manufactured locally. In the early 1990s the ICRC started the process of standardizing the techniques used in its various projects around the world, for the sake of harmonization between the projects, but more importantly to improve the quality of services to patients. Polypropylene (PP) was introduced into ICRC projects in 1988 for the manufacture of prosthetic sockets. The first polypropylene knee-joint was produced in Cambodia in 1991; other components such as various alignment systems were first developed in Colombia and gradually improved. In parallel, a durable foot, made initially of polypropylene and EthylVinylAcetate (EVA), and now of polypropylene and polyurethane, replaced the traditional wooden/rubber foot.
In 1998, after careful consideration, it was decided to scale down local component production in order to focus on patient care and training of personnel at country level.

# Introduction
The aim of this document is to describe a method for manufacturing trans-femoral (TF) prostheses using the ICRC's polypropylene technology as applied at the Physical Rehabilitation Centre in Addis Ababa.
The casting, rectification and alignment methods used correspond to international prosthetic and orthotic (P&O) standards of practice and are therefore not described in these ICRC manufacturing guidelines.

# ICRC Physical Rehabilitation Programme
Trans-femoral kits are available in adult and child sizes. 4A negative cast is taken in accordance with usual P&O practice.

# Trans-femoral cup alignment and socket manufacture
- The mould is filled to produce the positive, which is rectified according to the measurements taken.
- Chamfer the edge of the trans-femoral cup.
alignment of the trans-femoral cup 4Cover the mould with nylon.
Fix the nail at the bottom of the mould, where the cup will be attached.
Place the TF mould on the CR alignment jig; align according to the instructions on the use of the jig (separate manual). Make the alignment in accordance with the measurement card. Fix the cup to the socket with plaster of Paris (POP).
- Add a piece of EVA at the distal part of the cup.
This will prevent the PP from being drawn in during suction.
It will also facilitate opening.
- Cut a sheet of 5 mm PP according to the measurements (add cm to the circumference and 10-15 cm to the length).
Leave the PP in the oven at around 180 for about 20 minutes.
Drape the PP on the mould and open the vacuum suction.
ICRC Physical Rehabilitation Programme 4Cut off the excess PP.
Leave the vacuum on until the PP cools down.
- Wait at least 6 hours before opening.
Draw the trim line on the proximal part of the socket.
Use the oscillating saw to cut the PP.
Remove the plaster.
- Grind the distal part of the cup down to the EVA pad.
Use a screwdriver to remove the EVA.
- Grind the distal part until it is flat. Do not remove all the PP.
- Check that the surface is flat.
- Grind the distal part until it is flat.
- Grind the socket along the trim lines with the router.
- Use a sharp piece of glass to smooth the edge of the socket.
- Using a conical drill, make the hole for the cotton stocking or for the suction valve.
- Position the suction valve medio-laterally and distally to the plaster mould.
Use the suction valve ring to shape the plaster. Reduce the diameter of the plaster to allow for the thickness of PP used (4 or 5 mm). Smooth it nicely and break the edge. (see 2.1, page 6).

# Total-contact prosthesis
There are two ways of manufacturing a total-contact trans-femoral socket:
1. By the same procedure as for a conventional TF; 2. By welding the conical cup directly under the PP socket.
Manufacturing Guidelines Trans-Femoral Prosthesis 4Cover the mould with a nylon stocking.
Fix the cup with plaster in the usual way.

# mm 12 mm 6 mm mm
During the first fitting, glue a piece of EVA inside the cup in order to avoid air leakage.
Glue a 12 mm and a 6 mm piece of EVA inside the cup. Finally, use a 3 mm piece to cover the cup and the sides of the cup.
ICRC Physical Rehabilitation Programme 6Material needed for finishing.
- Glue the 12 mm and 6 mm EVA discs inside the cup.
- Lastly, glue the 3 mm EVA all around the cup.
- Drill a hole according to the diameter of the suction valve.
- Smooth the edge with a sharp piece of glass.
- Test the suction valve and check by adding water inside the socket.
- If the conical cup is used, it must be adjusted to the socket in accordance with the alignment.
Use the welding iron to make a groove between the socket and the conical cup.
- Use the hot-air welding gun to weld the cup to the socket.
This has to be done very carefully to avoid breakage during the first fitting.
- Components for 6 mm ankle disc only.

# ankle-foot alignment
An extra 4 mm plate must be attached to the convex ankle. (For 6 mm ankle disc only.)
Drill two holes as shown on the illustration below and fix the two components together with a PP welding rod. (For 6 mm ankle disc only.)
This will prevent breakage of the foot bolt.

# Manufacturing Guidelines Trans-Femoral Prosthesis
The building-up and bench alignment process -steps to follow
- Ankle-foot alignment - Socket alignment - Adjustment of length - Welding of cylinders - Alignment of finished prosthesis 6Preparation before fixation for 6 mm ankle disc only.

# BuIldIng up
The pROsThesIs and BenCh alIgnmenT 3 6For maximum strength of the assembly, the opening of the concave cylinder must be in front, and the reinforcement bar at the back.
ICRC Physical Rehabilitation Programme 6Fixation procedure.
- Final result for 6 mm ankle disc only.
The ankle alignment system allows dorsal and plantar flexion, medio-lateral movements so that the prosthesis can be adjusted to the heel height of the shoe.
The alignment can be adjusted for a heel height of between 0 mm and 20 mm, but a heel height of 10 mm is recommended.
The heel height is adjusted according to the patient's shoe; the concave cylinder must be perpendicular to the ground.
Manufacturing Guidelines Trans-Femoral Prosthesis 4The foot is adjusted in external rotations of 5.
- Check the alignment once again with the patient's shoe on the foot.
- Transfer this measurement from the foot up to the mechanical knee-joint axis.
ICRC Physical Rehabilitation Programme knee-ankle-foot alignment 6Same measurement.
- The measurement taken on the patient must be from the medial tibial plateau plus 1.5 to 2 cm to the ground.
- Draw a line with a marker according to the measurement taken.
Make another mark 9 cm from the first. This corresponds to the bottom of the concave cylinder minus 1 cm.
- Use the pipe cutter to make the cut.
Smooth the edges.
- Pay special attention to the rotation of the knee-joint with the foot.
Heat the distal part of the pipe with the hot-air welding gun.
Use a rubber mallet to insert the knee-joint into the concave cylinder as far as the mark.
socket and bench alignment length adjustment for normal stump length
The socket is connected to the conical cup (after length adjustment) with a convex disc in between. The conical cup is welded directly on top of the knee joint. The convex disc allows abduction, adduction, flexion, extension and shifting in all directions.
- Check the alignment and adjust the conical cup according to the measurements taken.

# Cup opening in front CORReCT
Cup opening at back InCORReCT 6The force patterns on heel strike are as shown in these illustrations. Breakages can happen easily.
- Make sure the conical cup remains horizontal in both planes before welding it. Check also knee alignment and foot rotation.
- The temperature of the mirror should be between 185 and 200 C.
- Hold the cylinder on the mirror welder for no more than 5 minutes until a roll of melted PP is formed.
Weld according to the marks and apply slight pressure.
welding the cylinders length adjustment for a short stump 1. The socket is connected to the conical cup with a convex disc in between.
2. The second conical cup is connected to the knee-joint with another convex disc in between.
3. Once the height has been adjusted, the conical cups can be welded together.
Static or dynamic alignment can be done either above the knee-joint or below the socket.
length adjustment for a long stump: pay attention to minimum dimensions (see below)
A 22 mm for convex/concave plates B 40 mm minimum distance between connection surface and axis of the knee 

# Belt manufacture
During the first fitting with the patient, the measurement for the belt is taken from the great trochanter, around the waist and above the opposite iliac crest as far as Scarpa's triangle.
The belt can be either a leather or a cotton strap, fixed with a 16 mm buckle.
Add 15 cm to the measurement taken on the patient to allow for adjustment during fitting.
pOlypROpylene COsmeTIC manuFaCTuRe 4 6All components have to be welded together.
- Drill a 5 mm hole in the concave cylinder and the pipe.
- Fix the expansion pin.
- When the PP has cooled down, grind the edges and weld.
- Protect the knee-joint with adhesive tape.
Grind the socket with sandpaper to roughen it.
Fill the socket with POP in order to fix the pipe.
- Shape the socket with plaster according to the measurement.
- Smooth the plaster and cover it with a stocking.
- Drape 4 mm PP around the socket in the same way as for the first socket.
- Once the PP has cooled down, remove the proximal part.
Use the oscillating saw to open the seam.
Remove the plaster and clean up the socket.
Trim the shell proximally and distally in line with the socket and the knee-joint.
Replace the shell on the socket.
Weld the seam.
Weld the proximal edge.
Weld the shell to the knee-joint.
- When the welding is completed, remove the excess PP.
- Grind the seam between the shell and the knee-joint. - The seam must be ground almost flush with the socket. - Grind the proximal edge of the socket.
These three parts must then be polished.
- Protect the pipe and the knee-joint with tape.
- Shape the shank with POP and drape a sheet of 4 mm PP over it.
- Open the shell and remove the plaster.
- Insert the prosthesis into the cosmetic shell.
Determine and grind the proximal trim line for maximum flexion of the knee-joint.
- Weld the seam and the ankle connection.
- Grind and smooth the welding.
- Insert an EVA washer cut to the same shape as the shank about 10 cm below the knee-joint to keep the cosmetic shank in place. This will also prevent creaking.
- Fix the knee-joint back onto the shank.
Fix the belt.
eVa COsmeTIC manuFaCTuRe 5 6Roughen the EVA before applying it to the PP socket. Glue layers of EVA on the socket and shape it. A final layer of 3 mm EVA will cover the entire prosthesis, increasing the circumference by 1 cm.
- Cut a sheet of 12 mm EVA corresponding to the circumference of the wooden or plaster model shank. Skive both sides of the EVA and glue.
- Place the sheet of EVA in the oven at about 120 until it becomes soft, then bend it to obtain a conical shape. Add talcum powder inside the cone and put it back in the oven.
- Pull the EVA cone over the model shank and tighten it with an elastic bandage, or use a vacuum system.
- Cut the posterior proximal edge to allow flexion of the knee-joint.
- Tip: for finishing purposes, wind a tape around the proximal aspect of the foot to prevent damage to the foot cosmetic during grinding of the EVA.
- Shape the shank according to the measurements taken on the sound leg.
Then glue it distally on top of the foot.
Insert an EVA washer cut to the shape of the shank about 10 cm below the knee-joint to keep the cosmetic shank in place.
Fix the shank to the socket. Fix the belt.