Willie Stewart of Team PossAbilities

Introduction to prosthetics

A prosthetic device is called a “prosthesis” is an external medical device designed to replace a missing or amputated body part such as an arm or a leg.

A prosthetist is a trained, highly skilled professional that designs, fabricates, and fits a prosthetic devices or which is more appropriately referred to as prostheses.

A prosthetists works with a team of assistants and technicians to fabricate and fit the most appropriate device for each individual patient.

How is a prosthesis made?

The prosthetist takes a mold (cast impression) of the persons affected arm or leg and modifies this mold of the limb to optimize weight-bearing areas.

Painful areas can be relieved or compensated for by adding to or deleting from the surface area once the socket is fitted. The mold is carefully smoothed by the technician and is prepared for vacuum forming.

Heating the plastic

When making a prostheses, the most important component is the socket. This is the part that interfaces (or connects) the body with the prostheses.

The team will discuss the design, and prepare a piece of plastic (such as Durr-Plex) by placing it in an oven at 375 degrees Fahrenheit for 15 minutes to make it pliable.

Molding the plastic

When the plastic is ready it becomes soft and moldable. It is removed from the oven to begin forming.

Vacuum forming

Since the plastic cools rapidly the team must work quickly to form it around the mold.

A vacuum system is applied to pull the plastic tight around the mold to ensure an intimate fit.

In about 30 minutes, the plastic is at room temperature and ready to be removed from the mold.

This plastic component will serve as a diagnostic "check socket" that will be fitted to the patient to ensure a proper and comfortable fit.

Attaching the components to the socket

The socket is now ready to be attached to the remaining components. The prosthetist and technician will work together to established the best "initial alignment" or "bench alignment."

Fitting the patient

This initial prosthesis will be fit to the patient. The prosthetist will align the components to optimize the function and safety of the device. This procedure is called "dynamic alignment."

When the fit is comfortable, and alignment is optimal, the device is returned to the lab and re-fabricated into the permanent prosthesis.


A patient with the new prostheses may come back from time to time to have minor adjustments to the fit, or alignment to make the new device more comfortable.

To make an appointment

Please call our office at: (909) 558-6272

Office location

Loma Linda Ambulatory Services Building
11406 Loma Linda Dr.
Loma Linda, Ca 92354
(909) 558-6272

Please come to the North Entrance