Upper Limb Prosthetics

The fitting process will vary by practitioner and amputation level, but my goal is to familiarize you with the overall procedure.  I have avoided numbering to stress that these “stages” may vary and that some may occur at many points throughout the process.

I have been told that one of the biggest factors in a successful outcome is a patient’s understanding of the process and realistic expectations.  The bigger the disparity between what the patient believes will happen and what does happen, the more likely they will be unhappy with the result.  All of us are limited by the same realities, but the less disillusionment and disappointment experienced along the way the better.

ASK QUESTIONS!   The more you know, the more involved you can be.  And the more involved you are, the more likely it will turn out the way you want.

Learn all you can.  Advocate for yourself.  Insist on dialogue.  A good prosthetist will be your partner through the process.  The goal is to provide you with a prosthesis that will enhance your life.

Initial appointment/evaluation

The Amputee Coalition of America has a list of ‘questions to ask your prosthetist’  but I want to expand on the topic and talk a bit about what the practitioner needs from you, too, and why.

Things to discuss with your prosthetist:

*Describe the circumstances of your amputation and your experience between then and now.  Have you had multiple surgeries?  Were there other injuries?  Have you had complications with your residual limb?  Infection? Neuromas?  Pain? 
All these things will go into determining what will be the best prosthetic system for you.

*What have your experiences been with prosthetics so far? – This tells us what your previous experiences have been like (good or bad) and how we can tailor our approach to reflect that.  It also gives us an idea of how much you know about the field already and how much explanation need from us.

*What are your ideas/beliefs/preconceptions about the technology and field in general? – This lets us know what you think is possible and what you are expecting.  The media likes to feature things that are exciting but still in development and not available to the average consumer.

*What have you tried in the past? – so that we may learn from the mistakes and not make them all again.

  •  Describe the prosthesis and the components used (bring it with you if you can!)
  • Explain any problems you experienced with the device itself or the process.
  • Any dislikes that may not have caused ‘problems’?
  • Did you receive training from the prosthetist or an occupational therapist in how to use the prosthesis?
  • What surprised you about the process or device?  What disappointed you? 
  • Why did you ultimately stop using the prosthesis, or what has brought you to their office now?

*What work did you do prior to your amputation?  Are you planning on returning to it?  What about it will be particularly difficult for you to do now?   - This tells us part of what you need from a prosthesis and assists in decision making.

*How much do you care about how it looks vs function?    This will influence component selection.  It is easy for us to dismiss ‘cosmetic’ concerns, but you are the one that has to wear it.

*What hobbies do you enjoy?  What activities do you enjoy doing the most?  What would make you happy?  The goal is to do more than just provide basic function.  It is to give you the tools to help you live a full life.

*What other health problems do you have?  This may have an impact on which system will work the best for you.  Some may be easier, some may not work at all.

*How motivated are you to use a prosthesis?  How much time, effort, and training are you willing to put in?  How good are you with gadget-y things?  This is another aspect of picking the right system for each individual.  Some people can’t or don’t want to spend time learning the intricacies of myo-electric prostheses.  

Some of these are difficult questions, but the earlier in the process you share these things the better.  This is when decisions are being made about what to try first and what you will be trying to obtain insurance authorization for.

*As you discuss options with your prosthetist, ask to have the pros and cons of each one explained to you.  What are the difficulties encountered with each choice?

This is one of the many places that a good dialogue provides both parties with valuable information.  No one is more familiar with you and your life than you.    Your insights are absolutely necessary.   The prosthetist may be able to provide you with a better understanding of the challenges and concerns patients in general (and therefore possibly you) will face down the road.

Insurance Authorization

For more information on insurance and  billing, refer to the "Insurance and Billing" page.

You can ask to be involved in this process.   You may have to do a lot of conversing with the insurance company if they deny the claim and you have to resubmit.  In addition, if you ever decide to go to another provider, you will have valuable information to share about what did/did not work and how to deal with them.

Myo site testing

Your prosthetist may use electrodes and a computer or hand held device to test for electrical signals (called EMG signals) in your residual limb that could be used to control a myo-electric device.  For more information about how that works, visit the Externally Powered page.

Your prosthetist will be looking for    1) the level/strength of signal    2) your ability to generate intentional, distinct, separate signals and    3) your ability to control the signal.  If you cannot do all those things at first, it doesn’t mean you won’t.  Most people have to work on conditioning those muscles like any other. With practice and training you may be perfectly capable of using a myo device.

Myo training and practice

This may be done with a prosthetist or occupational therapist.  There are computer games available to make the process more interesting and fun.  Unfortunately you would not have access to them at home, but hopefully the prosthetist or OT can show you exercises to do on your own.  The more you practice, the better! 

You may be impatient to get your prosthesis, but those with experience say that the more time you spend at this stage, and the more practice and skill you have when you receive your prosthesis the less frustrated you will be.


The prosthetist will take a cast of your residual limb or generate a computerized image using a scanner.  (technology we call CAD CAM article about)  The goal of both is to capture the shape of your unique residual limb and make a well fitting and comfortable socket.

Deciding to take a physical cast does not necessarily mean your practitioner is more ‘low tech’ than one who uses CAD-CAM.  I know technological wizards that still prefer casting because they feel they gain something from being able to feel the patient’s residual limb and to squeeze, press, and otherwise shape during the impression taking process.

But CAD-CAM allows one to store the image at various stages of modification (see below) permanently on the computer.  They can compare old and new versions, send the file digitally to manufacturers, and recreate the exact same socket in the future. 
There are benefits to each system

Behind the scenes: 

If a physical cast was taken, it will be filled with plaster to create a model of your residual limb.

The prosthetist will make modifications to the plaster or computer model in order to optimize the shape of the final socket.  He/she will purposefully “load” and “relieve” certain areas to take on more or less weight and pressure.  Some of these are based on standard principles of anatomy, and some will be according to your unique limb shape and problems with tenderness or pain.

If the modifications are done on the computer, a carver will translate the image into a physical foam model.

Hot plastic will be placed over the model to make a plastic ‘test socket’

Test socket fitting

The prosthetist will have you try on a clear plastic socket to test the fit and comfort.  The plastic can be heated and shaped to make adjustments as necessary.


When he has achieved the fit that he wants, a ‘diagnostic test socket’ is often created.  The test socket is used to make a working prosthesis with the componentry you intend to use in the final device.  This is especially helpful in the case of myo-electric prostheses to experiment with components and placement of electrodes.

Many adjustments will be made at this point.  The more bugs you can work out at this stage, the less you will probably have to do in the final product when it is much more difficult to make changes. 

You will also likely be changing during this time.  Prosthetists are faced with a dilemma:  statistics show that the sooner you are fit with a prosthesis after your amputation, the more likely you are to use it.  However, soon after your amputation you will be going through a lot of changes.  There will be swelling and pain, and as the limb heals it will change shape.  You will begin using those muscles again, and they will strengthen at different rates and in different ways.  As this happens the fit of the socket will change.    It may not be so comfortable anymore or it may not stay on.  Electrodes may not make good contact with the skin.  Your arm may stop responding the way you want and start to seem ‘finicky’, or you may have difficulty working it at all.  The things are, unfortunately, to be expected.  Adjustments can, and will, have to be made. 

This is one place where a body-powered prosthesis has some advantages.  You may not need an extended test socket phase.  Depending on your suspension system (method of keeping the prosthesis on) you may be able to wear prosthetic socks to add padding or take up lost volume.  Your prosthetist may be able to add pads inside the socket to do the same thing.

Final fabrication

At some point, your prosthetist will decide it is a good time to make the final prosthesis.  This usually consists of a laminated socket such as:

Prosthetic training

Many would argue that this is the most crucial part of upper limb prosthetic fitting.  Learning to use it is no small thing.  It takes lots of dedication and practice.  Usually this takes place with an occupational therapist.

They will work on such things as:

learning to operate the prosthesis
    - simple activities and props like stacking cones or blocks
    - practice handling objects of various sizes, shapes, and weights.
    - practice controlling the grip force by handling Styrofoam cups 
      without crushing them.

-  Practice with Activities of Daily Living (ADL's) such as:
    - self care activities like eating, dressing, brushing your hair 
      and teeth
    - household activities
    - driving 

Follow up

The part of the process that never ends.   Things will break and need to be repaired.  Your limb and fit of the socket will change.  Your life may change and the prosthesis may not be appropriate for you anymore.  Your goals, needs, and body will all change and evolve.  You prosthetist will have to make adjustments and adapt the prosthesis to keep up with you.

Every patient’s situation and needs are so unique.  There is no ‘standard’ approach.  Most of this field is done on a case by case basis.   

As I said on the home page, there is often a lot of customizing, adjusting, tweaking, problem-solving, and trial and error.  Done right, it requires more time and can be frustrating.  Success depends on dedication and persistence of the patient and the prosthetist.  


“Courage does not always roar.  
Sometimes courage is the quiet voice at the end of the day saying,
"I will try again tomorrow”

  – Mary Anne Radmacher