How to Make Prosthetics

Prostheses, also known as artificial legs and arms, can restore some normal functions for amputees. Each amputee is unique, which means each prosthetic must be custom-designed to fit the patient’s body.

According to the Amputee Coalition, prosthetics have a lifespan of about three years, but other factors contribute, such as your age, activity level, and growth. Since a prosthetic is an extension of your body, it’s important to have one that fits your physical ability and needs.

Working closely with a prosthetist who specializes in fabricating and fitting these prosthetic limbs is vital, especially since several steps go into making a prosthetic. Use this guide to learn more about how prosthetics are made.

Meet With a Prosthetists

Since prosthetic limbs aren’t mass-produced and found on shelves in stores, many are custom made from start to finish or have parts catered just to you. Similarly to dentures and eyeglasses, prosthetic limbs are prescribed by a medical doctor after you schedule a consultation. This typically occurs after you visit with a physical therapist and a prosthetist. If possible, this meeting occurs before the limb is amputated and involves the surgeon so that the prosthetist has as many details as possible.

In this meeting, you might discuss what goals you hope to reach with a prosthetic. That way, you can be sure that your team knows what’s important to you during your recovery. You might ask yourself these questions:

  • How active do you plan to be?
  • What activities do you plan to do with the prosthetic?
  • Do you care what the prosthetic looks like?
  • Post-operative, the surgeon and prosthetist decide upon the best dressing for the limb. This usually consists of a compression garment that promotes fluid evacuation and healing.
  • Measure the Body Segment

measuring leg prosthetic

Image via Flickr by the University of Salford

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One of the most important aspects of a prosthetic limb is how accurately it fits because the goal is to have it fit as naturally and comfortably as possible. Before the work on the prosthetic can begin, the prosthetist takes an impression and digital reading of the remaining limb. This step must wait until the residual limb is no longer swollen and the wound is fully healed, and this is usually several weeks after the surgery. From there, the prosthetist measures other relevant body segments and locates the bones and tendons in this residual limb.

Cast the Stump

Using the impressions and measurements gathered, the prosthetist makes a plaster cast of the stump. Most often, this cast is made out of plaster of Paris since it dries quickly and gives a detailed impression, but it can also be made out of fiberglass. From this cast or mold, an exact duplicate, or stump, is created. The cast or mold serves as a template for making the prosthetic, and the prosthetist transforms this into a positive model of your limb. This meticulous process is vital to create a wearable prosthetic.

Create the Socket

The socket allows the prosthetic device to connect to your residual limb. The prosthetist uses a large oven to heat clear thermoplastic and places it in the positive model. During this phase, the heated sheet simply goes on top of the mold while it sits in a vacuum chamber. The air that forms between the sheet and mold is removed from the chamber, so the sheet collapses around the mold and forces it into the exact shape of the mold. The result is the transparent test socket.

Check the Prosthetic’s Fit

Before a permanent prosthetic is made, the prosthetist must check the fit of the temporary one. Usually, a prosthetic fitting takes place two to six months after surgery since that’s how long it takes for the incision to heal and the swelling to subside. The prosthetist will place an additional layer called a liner on your residual limb. This liner gives you a barrier between the socket and your skin, providing extra cushion and allowing the socket to fit snugly.

If you’re missing a leg, the prosthetist will have you walk with the temporary one. Comfort is important, so you should share how it feels with the prosthetist. A poorly fit socket can give you blisters, pain, and sores. Plus, the more comfortable the fit, the more likely you are to use it. If adjustments need to be made, the prosthetist takes the test socket, reheats the thermoplastic, and adjusts the piece. It might take several visits to create a prosthetic that fits you and your needs.

Once the test socket fits perfectly, the prosthetist creates a permanent socket. This part is made out of polypropylene, so it can be formed the same way the thermoplastic is used on the test socket. It’s vacuum-formed over the mold to create a smooth and accurate socket.

Manufacture the Prosthetic Limb

Residency Program

When it comes to manufacturing the prosthetic, pylons attach to the socket and are covered by a foam cover. The pylons are made out of aluminum or titanium and then die-cast. With this option, liquid metal is placed into a steel die. For the foam cover, the prosthetist uses the usual plastic-forming methods, including vacuum-forming and injection-molding, with the latter forcing melted plastic into a mold and letting it cool.

To assemble the prosthetic, the prosthetist uses a torque wrench and screwdriver to secure the pieces together. After having you try on the prosthetic again, the prosthetist can make final adjustments to your custom-made prosthetic. Keep in mind that this prosthetic can last anywhere from several months to several years. You may need to adjust parts of the prosthetic to accomodate your activity levels or growth. Make sure you schedule regular appointments with your prosthetist to avoid major issues.

Contact Scheck & Siress

If you have any questions about the prosthetics process or want to meet with someone who has gone through the experience, contact Scheck & Siress. In business for more than 60 years, we provide our patients with quality pre- and post-operative patient care for orthotics and prosthetics. We have more than 18 locations found in Illinois, Indiana, and Wisconsin, allowing us to offer quality service to those throughout the Midwest.

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