“What is the hardest type of residual limb to fit for a prosthesis and why?”

Probably the hardest ones I fit are really bony BKs. Especially World War II vets who have been amputees for fifty-odd years, and it’s just skin over the tibia. [It’s hard] to find enough area to load up for, so that they can get a comfortable fit.

If it’s a really bony residual, hand casting does better than a Tracer. I usually have to do a five-stage cast. You mold sections at a time to make sure it’s a very intimate fit.

And diabetic patients who are [undergoing dialysis] go up and down [in volume]. You have to allow for the swelling. After they [undergo dialysis], they can go down four or five plys of socks. A lot of [the trouble] is patients’ understanding of how to manage the prosthesis.
Craig Talbot, CPO
Carolina Orthotics and Prosthetics Inc.
Charleston, S.C.

Hip disarticulation is one of the more challenging ones, because you’re replacing three joints as opposed to trans-tibial amputation, where you’re replacing just the ankle joint.

The prosthetic hip joint [has] to allow for flexion at the thigh and it [has] to be locked out so it doesn’t go into any hyperextension [while] standing. You have the difficulty of aligning all the [components], plus the lack of physiology [for the socket] to grab [onto] for weight-bearing.

If they’ve taken part of the hip away, [when] the patient is sitting in a chair without any device on, [he doesn’t] have the hipbones or the pelvic bones to stabilize [himself] even for sitting. So that socket is going to level the pelvis for sitting, as well as provide a platform for [components] for ambulation.
David S. Goris, LPO, CPO
Sonlife Prosthetics & Orthotics Inc.
Spring Hill, Fl.

Probably [the hardest limb to fit is] one with a lot of redundant tissue. It just hangs there, and you have to try to control the volume of it to fit it into the socket.

You have to look at the amount of tissue and what kind of setup [the patient is] capable of wearing, and it can vary from vacuum-assist systems, to the pull-in suspension, [to] ratchet locks.
Kim Duckett, CP
Fourroux Prosthetics
Huntsville, Ala.

As far as components [go], a Symes or Chopart amputation, or a knee disarticulation, is going to be the most difficult because of the length of the limb.

With knee disarticulations, because of the length of the limb, the mechanical knee is going to be further down than the sound limb. The patient does not walk as well, and cosmetically it’s not as good of a finish. There are multi-axis knees that will fold up under the socket, but that restricts the type of knee you can use. Inside the socket, if you do anything for comfort or fit, you’re also adding length to the limb.

If the problem is with fitting, the number one problem is a medium-to-short, below-knee, conical limb with very little muscle, because you don’t have anything to grasp or suspend with. You’ve got bone that’s underneath and you have to protect it. But there’s no soft tissue to work with as a cushion.

This is a problem for a lot of patients with older, more mature amputations, because the tissue in their residual limb atrophies.
Daniel G. Oglesby, CPO
Alabama Center for P&O/dba
Birmingham Limb and Brace Co. Inc.
Birmingham, Ala.

A very short above-elbow residual limb is pretty difficult. It’s also difficult when they take out the entire shoulder, because now you have to replace three different joints. Fitting that [limb] well has to do with your casting technique and where you apply pressure to keep the socket on, because you’re working against gravity. Since there’s not a whole lot to load on the limb, you have to load at specific points to get a suspension harness to stay on.
Trevor Towsend, CPO
Valley Institute of Prosthetics and Orthotics
Bakersfield, Calif.

For children, a very short and scarred residual limb—from burns or meningococcelmia—is difficult. With burn patients, they might have to fit the prosthesis over the burn garments.

When we have [someone with a lot of scar tissue], most of the time we have a custom-made urethane liner made. Those do very well for us. But we have to see the patients frequently—every four to six months because they’re growing.
Ed Skewes, CPO
Shriners Hospital
Greenville, S.C.