KAFO in Joint Lamination Technique

KAFO

in Joint Lamination Technique

Depending on the patient data and the orthosis' requirements, two production techniques are available for a laminated orthosis: Joint Lamination Technique or Anchor Lamination Technique.

In Joint Lamination Technique, the system anchors are embedded into the laminate while the system joints remain free. This production technique provides extra high stability. Based on the patient data and the selected system joints, the ideal production technique for the orthosis' production is also recommended in the orthosis configurator.

The orthosis of this online tutorial has been configured as well and produced in the following design:

  • unilateral system ankle joint
  • unilateral system knee joint
  • rigid foot piece
  • ventral tibial shell
  • dorsal femoral shell
  • Joint Lamination Technique

Here you will find an online tutorial for the Anchor Lamination Technique.

 Mounting Assembly/Lamination Dummies

Step 1/1

Mount the system joints by using the assembly/lamination dummies and in accordance to the exploded view drawing. When laminating, the assembly/lamination dummies serve as placeholders for the system joints' cover plates. Note: You can find exploded view drawings in our product catalogue System Joints and Articulated System Side Bars.

 Bending the System Stirrups/Anchors

Step 1/11

First, mark the lower edge of the assembly/lamination dummy on the system stirrup. Everything above this line must not be bent, as this area (the joint area) is a part of the system joint later.
Note: When you have acquired a bent system stirrup, you can skip the steps
1 to 4. 

Step 2/11

Clamp the system stirrup into a vice with plain jaws to bend it. Pay attention to the marking to avoid a subsequent deformation of the joint areas and to be able to bend very close to the joint.
Note: When you have acquired a bent system stirrup, you can skip the steps
1 to 4.

Step 3/11

Adapt the system stirrup to the shape of the model. Bend the system stirrup neck with a bending iron. Only bend in one direction. Note: Do not use a hammer and do not heat the material.
Note: When you have acquired a bent system stirrup, you can skip the steps
1 to 4.

Step 4/11

Remove the system stirrup from the vice and check the distance from the system stirrup to the model.
Note: When you have acquired a bent system stirrup, you can skip the steps
1 to 4.

Step 5/11

Adapt the system stirrup to the shape of the model. Bend the lower part of the system stirrup with a bending iron. Only bend in one direction.
Note: Do not use a hammer and do not heat the material.
Check the distance to the model.

Step 6/11

Adapt the system stirrup to the shape of the model. Bend the system stirrup foot with a bending iron. Only bend in one direction.
Note: Do not use a hammer and do not heat the material.
Check the distance to the model.

Step 7/11

Press the system anchor to the joint’s upper part by using a washer and a screw. To do so, use a torque screwdriver and a torque of 6Nm. Then, remove washer and screw again. 

Step 8/11

Fix the system anchor with the screw (farther away from the joint) at the joint's upper part before you begin bending.

Step 9/11

While bending, please consider the applicable bending radii and use a bending iron with round edges.
Note: You will find information on bending radii and the tools to be used in the manual for System Side Bars and System Anchors.

Step 10/11

Check the distance from system anchor and stirrup to the positive cast. Please make sure to have enough space left for the reinforcing profile and the reinforcement layers in order to avoid later strains to the laminate. Thus, the joint areas stay parallel.

Step 11/11

Grind the system stirrup and the system anchor. Always grind in direction of rolling. Remove all notches from bending and avoid sharp edges.
Note: System ankle joints with dorsiflexion stop, which can be adjusted by filing, should always be mounted in their pre-assembled neutral position without changing the dorsiflexion stop.

 Preparing the System String

Step 1/19

Use the activator spray as basis by spraying it thoroughly on both sides of the system anchor. Begin above the assembly/lamination dummy.

Step 2/19

Use some stockinette as underlay when attaching the profile core. Heat the profile core and adhere it from below to the system anchor with medium viscous fast-acting adhesive.
Note: Mind the safety data sheet when using fast-acting adhesive.

Step 3/19

Pull at the stockinette from both sides and press the profile core from below to the system anchor in order to fix it there. 

Step 4/19

Example for the course of a profile core on a unilateral KAFO.
Note: With this course, you set the stiffness of an orthosis in the particular areas.

Step 5/19

Only reinforce the profile core of the tibial shell. Add some medium viscous fast-acting adhesive to the system anchor and profile core. Heat a second profile core and adhere it to the first.
Note: Mind the safety data sheet when using fast-acting adhesive.

Step 6/19

Example for the course of a ground profile core on a unilateral KAFO.
Note: Have the profile core cool to room temperature before removing it from the model to avoid differences in distance due to material shrinking.

Step 7/19

Reinforced profile core of the tibial shell (A) in comparison to the non-reinforced profile core of the femoral shell (B)

Step 8/19

If necessary, you can also reinforce the medial side of the femoral shell with a profile core.

Step 9/19

Insulate the system knee joint. Remove the extension stop. Insulate this area and reinsert the stop. Insulate the joint areas of the joint's lower part with a thin layer of insulating wax. Fill all hollows and grooves which shall remain resin-free as well.
Note: Use a small syringe in order to apply the insulating wax in a simple and accurate way.

Step 10/19

Also insulate the areas and edges of the joint’s back with a thin layer of insulating wax and fill the bores for the extension stop dampers.
Note: Use a small syringe in order to apply the insulating wax in a simple and accurate way.

Step 11/19

If the system joint has a spring duct, disassemble the spring unit. The pressure screw remains mounted. Then, fill the spring duct with insulating wax.
Note: Use a small syringe in order to apply the insulating wax in a simple and accurate way.

Step 12/19

Insulate the joint areas of the joint's upper part, the sliding washers and all areas of the assembly/lamination dummy with a thin layer of insulating wax. Also, fill all hollows and grooves of the assembly/lamination dummys with insulating wax. Insulate all screw threads.
Mount the parts.
Note: Use a small syringe in order to apply the insulating wax in a simple and accurate way.

Step 13/19

If applicable, fill the injection bores of the assembly/lamination dummy with insulating wax. By doing so, you fill spaces between the system joint and the dummy, that result from the assembly. This reduces the working load when cleaning the system joints later.
Note: Use a small syringe in order to apply the insulating wax in a simple and accurate way.

Step 14/19

Clean all areas (from all sides) which shall be embedded into the laminate later. Remove insulating wax and grease residues.

Step 15/19

Pull carbon fibre braided tube over the profile core of the tibial shell (incl. system anchor).

Step 16/19

Insulate the system ankle joint. Fill all screw threads as well as all hollows and grooves of the system ankle joint with insulating wax.
Note: Use a small syringe in order to apply the insulating wax in a simple and accurate way.

Step 17/19

Insulate the joint areas of the system stirrup and the joint’s upper part as well as all areas of the assembly/lamination dummy with a thin layer of insulating wax. Insulate all screw threads as well as all hollows and grooves of the assembly/lamination dummy with insulating wax. Insulate the sliding washers, too.
Note: Use a small syringe in order to apply the insulating wax in a simple and accurate way.

Step 18/19

Clean all areas (from all sides) which shall be embedded into the laminate later. Remove insulating wax and grease residues.

Step 19/19

Pull carbon fibre braided tube over the system stirrup.
Fix it as close to the joint as possible by sewing and/or tying it with aramid fibre roving. Then, stretch the fibres and fix the other end too, if applicable.
Important! Only the stretched fibre can take on load and release it again!

 Reinforcing the KAFO

Step 1/33

If the positive cast is still wet, insulate it with compression film first. Then, pull a PA reinforcement stocking over the positive cast. Now, the PVA film tube can easily be pulled over as base film layer.
Note: We recommend to use a 0.10mm thick film layer.

Step 2/33

Reinforce the rolling-off area (arrows) of a rigid foot piece with carbon fibre band and a brim in order to increase the orthosis’ rigidity and prevent any movements.
Important! Already consider the shape of the later worn shoe when reinforcing the foot piece in order to gain the best possible fit. The width, in particular, can hardly be adapted subsequently.
Note: If the brim should be too high, it can easily be adapted later on.

Step 3/33

We recommend to use electrical scissors (e.g. Easy Cutter) to cut the separate fabric layers (carbon as well as aramid).
Note: Use adhesive transfer tape without backing material to fix the cutting edges. This  way, the edges will not fray.

Step 4/33

Dry the aramid fibre fabric at 120°C in an oven for at least one hour.
Thus, you remove any moisture that has been absorbed during storage and improve the fabric’s properties for further processing.

Step 5/33

Scarcely cover a carbon fibre fabric pre-cut with adhesive spray and adhere it to the entire sole. At first, only reinforce the sole and the area below the joint retainer at the foot piece to avoid unnecessary thick edges and gain a high stiffness.
Note: Always only spray the pre-cut which still needs to be adhered and not the already adhered reinforcement.

Step 6/33

Spare the area of the joint retainer.

Step 7/33

Reinforce the forefoot area with unidirectional carbon fibre band (e.g. 10cm width). Always reinforce up to the toes. Have the pre-cuts getting longer towards the heel to gain a smooth transition. Begin with the shortest pre-cut. Mind the direction of the fibres (arrow).
Note: Always only spray the pre-cut which still needs to be adhered and not the already adhered reinforcement.

Step 8/33

Reinforce with carbon fibre fabric and unidirectional carbon fibre band to form an optimal fibre composite.
Note: Always only spray the pre-cut which still needs to be adhered and not the already adhered reinforcement.

Step 9/33

Attach unidirectional carbon fibre band transversely below the joint retainer at the foot piece. Mind the direction of the fibres (arrows). Use as many layers of carbon fibre band as you need (this is an exemplary picture).
Important! Take care to use the fibres stretched!

Step 10/33

Reinforce with unidirectional carbon fibre band in a v-shape. Mind the direction of the fibres (arrows). Use as many layers of carbon fibre band as you need (this is an exemplary picture).
Important! Take care to use the fibres stretched!

Step 11/33

Reinforce the area of the lower leg with carbon fibre fabric. Spare the joint retainers. Use as many layers of carbon fibre fabric as you need (this is an exemplary picture).
Note: Always only spray the pre-cut which still needs to be adhered and not the already adhered reinforcement.

Step 12/33

Attach unidirectional carbon fibre band above the joint retainers. First, adhere a strap transversely around the lower leg. Then, reinforce along the profile core. Mind the direction of the fibres (arrows). Use as many layers of carbon fibre band as you need (this is an exemplary picture).
Important! Take care to use the fibres stretched!

Step 13/33

Mark the future partially flexible seating area on the film. Follow the modified edge.

Step 14/33

Attach carbon fibre fabric in order to reinforce the lower femoral shell area. Use as many layers of carbon fibre band as you need (this is an exemplary picture).
Cut the aramid fibre fabric and attach it to the seating area (mind the mark). Reinforce with the aramid fibre fabric slightly over the carbon fibre fabric in order to form an optimal fibre composite. Use as many layers of aramid fibre fabric as you need (this is an exemplary picture). Work as precise as possible as aramid fibre fabric is difficult to grind.
Important! Take care to use the fibres stretched!

Step 15/33

Attach unidirectional carbon fibre band above the joint retainer (1). Then, reinforce along the profile core (2) and along the band (3). Mind the direction of the fibres (arrows). Use as many layers of carbon fibre band as you need (this is an exemplary picture).
Important! Take care to use the fibres stretched!

Step 16/33

Example for a reinforced femoral shell from lateral (1), posterior (2) and
medial (3)

Step 17/33

Apply some insulating wax to the threads of the joint retainers in order to seal them airtight for the following steps.

Step 18/33

Mount the assembly/lamination dummies with system strings to the joint retainers. Screw the retaining screws through the base film into the joint retainers. Please make sure to screw in the screws only so far that they are gripped by the threads. Thus, you can compensate a changed difference between the system joints.
ATTENTION! If screws have to be unscrewed again, the base film may be damaged in the process!

Step 19/33

If the retaining screws are screwed in the joint retainers, you can now tighten the screws entirely. Insulate all screw threads subsequently.

Step 20/33

Fix the profile core with its carbon fibre braid on the model to reinforce the medial femoral shell (2). Attach carbon fibre braid to reinforce the tibial band (1) and carbon fibre braid to reinforce the femoral band (3). Make sure there is a direct connection to the system string or to the medial reinforced profile core.
Important! Take care to use the fibres stretched!

Step 21/33

Fix the lower end of the carbon fibre braided tube with spray adhesive at the sole of the foot piece.

Step 22/33

Attach unidirectional carbon fibre band diagonally below the joint retainer at the foot piece. Use as many layers of carbon fibre band as you need (this is an exemplary picture).
Important! Take care to use the fibres stretched!

Step 23/33

Keep on reinforcing. Mind the direction of the fibres (arrow). Use as many layers of carbon fibre band as you need (this is an exemplary picture).
Important! Take care to use the fibres stretched!

Step 24/33

Then, attach one strap of carbon fibre band directly below the joint retainer at the foot piece. Use as many layers of carbon fibre band as you need (this is an exemplary picture).
Important! Take care to use the fibres stretched!

Step 25/33

Keep on reinforcing. Use as many layers carbon fibre fabric and band as you need for the foot piece (this is an exemplary picture).
Important! Take care to use the fibres stretched!

Step 26/33

Attach a final layer of carbon fibre fabric to the foot piece. Cover the assembly/lamination dummy up to one half.
Important! Take care to use the fibres stretched!

Step 27/33

Attach unidirectional carbon fibre band to the lower leg area again. This time, attach one strap along the carbon fibre braid to reinforce the upper tibial shell area. Mind the direction of the fibres (arrows). 

Step 28/33

Then, attach one strap along the profile core (1) and after that above the assembly/lamination dummy (2). Mind the direction of the fibres (arrows). 

Step 29/33

Attach a final layer of carbon fibre fabric to the lower leg area. Cover the assembly/lamination dummy up to one half. Use as many layers of carbon fibre fabric as you need (this is an exemplary picture).
Important! Take care to use the fibres stretched!

Step 30/33

Attach unidirectional carbon fibre band to the upper leg area again. Attach one strap along the carbon fibre braid to reinforce the lower femoral shell area (1), along the lateral system string (2) as well as along the medial profile core (3). Mind the direction of the fibres (arrows). Use as many layers of carbon fibre band as you need (this is an exemplary picture).
Important! Take care to use the fibres stretched!

Step 31/33

Reinforce the area of the upper femoral shell area with aramid fibre fabric. Use as many layers of aramid fibre fabric as you need (this is an exemplary picture). Work as precise as possible as aramid fibre fabric is difficult to grind.
Important! Take care to use the fibres stretched!

Step 32/33

Reinforce the area of the lower femoral shell area with carbon fibre fabric. Use as many layers of carbon fibre fabric as you need (this is an exemplary picture). Cover the assembly/lamination dummy up to one half with a final layer of carbon fibre fabric.
Important! Take care to use the fibres stretched!

Step 33/33

Finally, in order to fix the reinforcement layers, pull a decorative fabric (2) or a PA reinforcement stocking (for a carbon look) over the model (1). Thus, the PVA film tube can easily be pulled over as top film layer (3).
Note: We recommend to use a 0.10mm thick film layer.

 Laminating the KAFO

Step 1/3

This production technique is especially adapted to our epoxy resin and hardener.
Important: Please consider the processing instructions and the safety data sheets for our epoxy resin and hardener. Precisely stick to the mixture ratio and thoroughly mix resin and hardener.

Step 2/3

Let the fabrics soak completely and rub surplus resin out. Press out the foot piece in order to receive the highest possible fibre volume ratio. While doing so, protect the film with some padding material and make sure to maintain the form of the modified pitch.
Note: Use available shaping dummies.

Step 3/3

Have the model harden over night (at least 10 hours), under vacuum and at room temperature.
Important! Here, again, please consider the processing instructions for epoxy resin.

 Cutting the KAFO

Step 1/5

Use a sharp knife to remove the thin laminate layer over the assembly/lamination dummies. Remove the screws.

Step 2/5

Mark the cutting lines on the laminate. To do so, prolong the cutting lines of the assembly/lamination dummies (blue lines), which enable you to cut out the orthosis as close to the joint as possible. In addition, also draw the orange line. 

Step 3/5

Carefully lever the assembly/lamination dummies of the system joints out of the laminate. Make sure not to damage the joint areas in the process.

Step 4/5

Use an oscillating saw to saw along the edges in order to remove the orthosis parts from the model. You can see the recommended saw blade in the picture. Thus, you can saw very close to the system joint without damaging it.

Step 5/5

Remove all laminate parts which are no longer necessary. Then, you can remove the orthosis parts from the model.

 Tempering and Grinding the KAFO

Step 1/4

Clean all the joint areas as well as the system stirrup before you temper the parts of the orthosis. Heat all wax residues with a hot air blower (1) and blow the liquefied insulating wax out of the hollows (2). Remove all residues with a
cloth (3). Remove the PVA film tube as well.

Step 2/4

Temper all parts of the orthosis before you grind them. Place the orthosis parts into a cold oven and heat it up slowly. When tempered, the parts of the orthosis are stable and can be worked in the best possible way.
Important! Here, again, please consider the processing instructions for
epoxy resin.

Step 3/4

Grind the edges of the orthosis parts (e.g. with an angle grinder). But absolutely avoid producing predetermined breaking points!
Note: Aramid fibre can be worked with sharp scissors.

Step 4/4

In order to remove all possibly caused notches, remove resin residues from the joints' surfaces with a sharp knife and polish them subsequently (e.g. with a marbling tool).

 Mounting the System Joints

Step 1/1

Mount the system joints according to the assembly instruction in the manual of each respective system joint.
Note: You can also find manuals in the download area.

 Applying the Padding Material

Step 1/3

Cut some attachable padding material into shape for the orthosis (e.g. the xDry towelling padding material).
Note: You can use the dummy for the padding material as a template.

Step 2/3

Adhere hook dots to appropriate areas of the orthotic shells. Attach the padding material.

Step 3/3

Now, the orthosis can be tried on.

 Alignment of the Orthosis

Step 1/1

The alignment of the orthosis is based on the individual, gait-related normal posture of the patient. In mid stance, this results in a gait pattern that is as physiological as possible.