Date: 10.23.18
Location: Hanger Clinic, La Crosse, WI
Tour guides: Luke and Mike
Students: The entire team
Time: 9:20-10:45 AM
Questions for Hanger Clinic Staff
1.
If we add a component that has spring force can you compensate in the design of the prosthesis? Yes.
2.
Where can we play? In what spaces can we build/modify?
Higher on the Freedom foot is better (on the “C” part of the foot). We can build on both sides of the foot. Epoxy can be used and we can rough up the surface to do that if needed. We can build almost anywhere except where it would restrict the movement of the split toe or effect the placement of the foot.
3.
What is off limits (don’t drill holes or modify)?
Can’t drill in the carbon fiber or even scratch it. We could drill an 1/8” hole in the aluminum tube on the lateral sides where tension and compression forces would be reduced, but he said we would have to ask the engineer for sure. We can use the split in the toe to run wires through but warned the carbon fiber edge is sharp so the wire would have to be protected. Luke recommended some clamping mechanism to hold on our components as opposed to drilling.
4.
Is there a space we can harvest vertical or linear movement?
Luke did not have any more insights on this other than what we have already talked about. He did mention the spring force rebound as the foot rolls off the toe.
5.
How much motion should we expect in a heel deflection when it strikes the ground? He felt the average would be between 0 and ½”. The heel should never bottom out. If it does it is a design flaw and it could crack the carbon fiber. He also felt the majority of “feet” are like the Freedom foot we have to work with. Some will vary in height, but the one we have for testing is representative for the average. The heel is the damper, the forefoot is the storage and energy release.
6.
Any rotational movement when the prosthesis strikes the ground? Yes, the knee and ankle can rotate a little. When people run they run on the outside of the foot. When they walk the walk on the inside of the foot. They fit the foot based on the average % of running and walking the patient will do. This is done on a treadmill to finalize the fit.
7.
Where can we drill holes? Basically nowhere unless we can drill in the tube.
8.
Can the inside of the tube be used?
Yes it can. It is open for us to use same as the outside of the tube. Luke did not seem to be concerned about something sticking out from the tube.
9.
What is the weight budget for the foot? How much weight can we add before it is too much?
Luke said it would be no problem adding a reasonable amount of weight. People have Freedom Feet that weigh 3 times what ours does and they have no problem with it.
10.
What is the range of motion when someone steps? What does it look like?
Heel strike first then roll to toe and spring off to the next step. It is important for the toe to have spring to help move the limb toward the next cycle.
Other notes:
•
If something breaks on the Freedom foot, they have to send it back to the manufacturer who determine if it is a design flaw or they made a mistake fitting the prosthesis.
•
The rubber feet are molded to fit over the freedom foot and they have a molded in heel inside to give additional lift.
•
Some people do not use the rubber feet, they glue on tire rubber to the bottom of the foot and use that during the winter.
•
There is a 3.5 year warrantee on the Freedom Foot.
•
A mid length amputation is the easiest to work with. That is defined as 6” below the knee on an average person.
•
Average toe deflection on a Freedom foot is up to ½”.
•
The mechanical knee is designed with a geometrical locking mechanism to allow the natural movement of the knee forward before starting to initiate the bend.
•
The shorter the amputation, the more the prosthetic fitter has to work with.
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| Students at Hanger Clinic |
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| Students seeing how a prosthetic limb is made. |
Email from Clint at 5280 regarding SmartPuck Components:
Awesome! Let us know how we can help.
The fixture we sent will allow the students to see how the vacuum affects the limb. If the liner top is reflected over the top edge of the socket (with the bulk of the liner in the socket). You can see how the liners is drawn to the walls of the socket when the vacuum pump is activated. It takes a while due to the amount of air in the socket.
We can send other prosthetic components if you need them (feet etc).
Good luck,
