Using a Prosthesis in a Partially Amputated Hand

Getting  a prosthesis that helps a partially severed hand is actually harder than getting a prosthesis which works in a completely severed hand.  Hand prostheses can be difficult and the technology does not yet exist that provides for a functional partial hand prosthesis. 

Pain is the most common complication of a partial hand amputation, even more than if the entire hand and wrist are amputated.  There tends to be a lot of scar tissue in amputated hands and there is usually a significant loss of the range of motion of the fingers left on the hand.  Sensation can be lost in the more proximal part of the hand and this must be assessed as loss of sensation can be just as dangerous as having hypersensitivity of the stump. 

The Goals of Partial Hand Prosthetics

The idea is to establish some increased functionality of the hand without putting undue pressure on the part of the hand that is left.  The hand is not usually very well padded so prosthetics can rub on sensitive areas of the residual hand.  A good prosthesis should be comfortable and should allow the person to do things that require the use of two hands in whatever capacity that can happen.  In addition, people who suffer partial or total hand loss will overuse the opposite hand and will begin to experience pain and disability of the good hand. 

It is virtually impossible to have a single prosthetic device for the partially amputated hand that is both functional and aesthetically pleasing.  For this reason, many hand amputees have two different prosthetics—one for function and another for aesthetics.  Passive prosthetics offer no increase in range of motion but can be used to stabilize the hand in such a way as to allow for it to be used in two-handed operations. 

There are body-powered prostheses for the partially-severed hand.  Some are driven by cables while others are driven by movements of the hand and wrist. These can be uncomfortable to wear and generally do not restore a great deal of function. 

Task-specific prostheses can be used whenever a particular task needs to be performed.  Most are customized to the exact deficit the patient is experiencing. 

Stages of Prosthetic Care

There are generally three stages of prosthetic care:

1. Preprosthetic hand care. In this phase, the hand is exercised and scar tissue/contractions are minimized as the hand heals enough to accept a prosthesis.
2. Preparatory prostheses care.  This is when prosthetics are used in order to regain functionality as soon as possible.  Research has shown that, when functionality is quickly restored, the patient has a better finished outcome.
3. Definitive Prosthesis care.  This is when the final prostheses are defined and used by the patient.  As mentioned, more than one prosthesis may be needed in order to have functionality over a wide range of activities.  Aesthetically-pleasing prosthetics can be worn and used in this stage of care.  

Prosthetics for the hand are suspended using roll-on liners, suction liners and designs which use the shape of the remaining hand in order to keep the partial hand prosthesis snuggly attached to the rest of the hand.  Prostheses can be made using flexible plastic or silicone; these are what most passive prostheses are made of.  These prostheses can be extremely lifelike in appearance.  Other prostheses can be devised to be body operated or operated through externally-powered methods.  In such cases, electrodes can be activated that make the prosthesis work in the desired way.