Fitting Your Prosthesis
Once an office visit has been scheduled, most people are eager to get through the fitting process and begin using their new prosthesis as soon as possible. The fitting process has two distinct phases: the temporary or preparatory prosthesis and the final or definitive prosthesis. The longer of these phases is the temporary prosthesis. For the new amputee, fitting usually begins when swelling in the residual limb is under control and the suture line has healed (4 to 6 weeks after surgery). Your physician will write the actual prescription for a prosthesis when they feel the limb has healed sufficiently. For experienced prosthetic users, your prosthetist and insurance company or other payer will help determine when it is time to be fit for a new prosthesis.
As your prosthetist evaluates and measures your residual limb, you will have an opportunity to talk about your rehabilitation goals and the expectations you have for everyday life as a prosthetic user. Do you plan on returning to work? Participating in sports? Going for daily walks at the park? How active do you think you will be? This information will help your prosthetist create a prosthesis that is right for your lifestyle.
Whether for upper or lower extremity, the structure of your prosthesis will include: a socket that fits over the residual limb; a strap or harness to aid in suspension; a sleeve or liner that helps you put on (don) the socket; and various components including pylons, rotators, manual and electronic joints (hip, knee, ankle, shoulder, elbow, wrist), and a foot, hand or other terminal device.
The socket is where the prosthesis and the body connect, making it the most critical element in prosthetic design. How the socket fits has everything to do with how well you will rehabilitate and recover your lifestyle. Your socket needs to be comfortable. The Hanger ComfortFlex™ Socket System involves a detailed fitting and fabrication process that begins with the temporary prosthesis.
The series of initial measurements your prosthetist takes enables them to fabricate a socket that is the exact shape and size of your residual limb. There are two ways to create a precision form for your socket: traditional, hand-casting with plaster or laser scanning with a computer. Depending on the unique characteristics of your limb, the prosthetist may choose to make a plaster mold of the residual limb. Wet bandages are carefully wrapped around the residual limb; when dried, this creates a rigid mold that captures the contours of your limb exactly.
The second option, laser scanning with a computer, is available in many Hanger patient care centers. The residual limb is scanned using the handheld Insignia™ three-dimensional laser scanner. Images that are exact to within one millimeter are stored in a computer and carefully reviewed by the practitioner and patient. Sensitive areas that require pressure relief are identified and the scan is carefully altered to reflect the unique characteristics of each patient. The final modified scan is then sent to Hanger’s central design center and the specifications are fed directly to an automated carver. The result is a precision form that is used to fabricate the actual prosthetic socket. For people who are still recovering from surgery, Insignia™ makes the fitting process more comfortable. They are not required to stand and there is no need to wrap or squeeze an injured area of the body. Insignia™ is a good tool for designing post-operative, preparatory, temporary and permanent prosthetic sockets for both lower extremity and upper extremity users.
Fitting the Temporary Socket
Whether your prosthetist chooses traditional casting or scanning with Insignia, the next step in the process is creating the temporary socket. Test sockets are clear so it is easy to see how your limb contacts the socket and to look for pressure spots. The other components that comprise your prosthesis will be added to the temporary socket so you can begin standing and walking, or utilizing your arm and hand. The temporary socket and other components will be adjusted and modified as you use the limb and give feedback to your prosthetist. For new amputees, the temporary prosthesis may be worn for a few months as your residual limb continues to reduce in size and mature. For people who have worn a prosthesis before, the temporary prosthesis is a much shorter stage in the fitting process and will be worn for a few days to a few weeks. The temporary prosthesis does not usually have a cosmetic covering since adjustments will need to be made as the residual limb continues to decrease in size. In most cases, different prosthetic components will be used in a temporary prosthesis than will be used in a definitive prosthesis. The temporary will usually be heavier and bulkier than the definitive prosthesis.
A key part of your recovery will be engaging in physical therapy during and after the fitting process. Some people, especially upper extremity users, will also need to have occupational therapy. Physical and occupational therapists will design rehabilitation plans that help you meet your lifestyle goals.
The Final or Definitive Prosthesis
Your prosthetist will decide when it is time to cast the final or definitive prosthesis. For new amputees, it will be several months after surgery, when the size and shape of the residual limb has stabilized. For experienced prosthetic users, casting for the definitive prosthesis will occur more quickly. Working from the modified temporary socket, your practitioner will create a final custom socket. All other components of the prosthesis will be attached and there will be options for a cosmetic covering. Some people prefer the look of their prosthesis without a cosmetic covering or cosmesis. Creating this prosthesis and perfecting the fit will require several visits and can take a few weeks to complete.
Remember, the terms “final” or “definitive” prosthesis can be misleading. Unfortunately, no prosthetic leg or arm is going to last for the rest of your life. Depending on daily use and activity level, a prosthesis can last anywhere from two to five years. With children, the time frame is even shorter due to their continuous physical growth. It is important to remember that a prosthesis is a mechanical device that sometimes needs repairs. Also know that significant weight gain or weight loss can require adjustments to be made to the socket or other parts of the prosthesis. Sometimes single components are replaced rather than creating an entirely new prosthesis.