A Prosthesis is a mobility aid just like a wheelchair or crutch. The prosthetic field is enormous. Different manufactures all over the world compete as far as prosthetic feet, knees and liners are concerned. Surfing the net the pro-active amputee can easily be caught up in a minefield of choices.
Usually frustration sets in when a patient has various problems with their artificial limb especially when it is your first prosthesis on a newly amputated stump.
So in an attempt to clear the clutter I am going to ask and answer the following questions.
What are the important factors in a good prosthesis?
People’s needs are different. One patient might say “I just want to walk without crutches”, another wants to actively compete in sport, and a third might feel they just want to look normal again.
Whatever your needs any prosthesis has to comply to the following three criteria.
Conventional Peg Leg
(Picture: Computerized Rheo Knee)
Socket comfort is the most important factor.
The socket refers to the bucket or surface, the stump rest in or upon. In other words this is where the patient makes contact with the prosthesis.
Millions are spent on socket comfort development worldwide.
Socket design must be the most researched topic in prosthetics for the following reason. If your socket does not fit comfortably and causes pain and or skin break down, it does not matter what kind of components the prosthesis consist of, it is useless to the patient.
(Picture: Ischial containment type above knee socket design)Furthermore, if the socket does not contain the skeleton and soft tissue in a functional way, you won’t be able to control the prosthesis effectively. (e.g. when it fits too loosely the prosthesis will rotate. I refer to this as a bath plug fit.)
A socket must be designed in such a way that the weight distribution is more where the patient can accommodate it easily and less on sensitive areas.
The liner a patient uses refers to the cover pulled over the stump before it is inserted into the prosthesis and is an essential part of socket comfort. It has got a pin or suction attachment distally that clicks or sucks onto the prosthesis inside the socket. This type of suspension eliminates the bulky leather straps of a few years ago.
(Picture: Conventional quadrilateral above knee socket design)Different manufacturers have developed different types of liners, for example silicone liners, aloe vera impregnated liners, mineral oil based liners and techno gel liners to name a few.
The type of skin, amputation level and diagnosis of a patient plays a vital role in liner choice. A diabetic patient or a patient with scar tissue or skin grafts would require different liners from a patient with good skin coverage.
Although I feel that too much emphasis is placed on stump liners and too little on socket design I must stress that the choice of liner is vitally important.
(Picture: Patient wearing Seal in Liner with C-Leg.)
All components available at this time are delivered to the prosthetist with certain alignment criteria. The criteria have been researched by the manufacturer to ensure that the component can be utilised to its full potential.
By not following the criteria it will spoil what could be a functional prosthesis. This is very important information to especially the first time amputee faced with the huge cost difference in different prosthetic components. In reality, you have just survived one of the most traumatic experiences known to man and now you have to make another unpleasant discovery. Most of your top medical aids will pay R100 000 for an internal prosthesis like a knee replacement but they will only pay R12 000 for orthopaedic appliances of which prosthesis’ are a part.
(Picture: Patient wearing Mauch Knee with Flex Foot.)
A well aligned R5 000 knee will be more effective than a R85 000 knee where the alignment is not set correctly especially in the first few months in the life of a new amputee.
Although not a necessity, the laser equipment available to prosthetists is a very efficient way of setting the alignment of prosthesis.
It is a good idea to set the alignment with the prosthesis wearing your favourite shoes and thereafter using shoes with the same heel height.
I am placing components third because it’s only the third most important factor. In the same breath I want to say that a mechanical knee cannot compare with a fully computerised hydraulic knee.
(Picture: Static Alignment with laser line )In comparison a stainless steel wheelchair can not compare with a fully customized titanium one.
When it comes to components it is usually a question of money. But remember I am placing it third in the line up of importance.
A prosthesis is either manufactured according to an exoskeletal or endoskeletal system. With an exoskeletal prosthesis the skeleton is on the outside (like a grasshopper). This is usually a hard prosthesis made from wood or composite material. Once finished there is very little adjustment available.
These days most prosthesis’ are made on the endoskeletal system. The prosthesis consists of a socket, knee and foot that are assembled by a variety of tubes, clamps and adaptors. When the limb is finished it can be covered by a foam cosmesis and cosmetic stocking or cosmetic skin can be sprayed on according to the patient’s natural skin tone. It can also be covered by silicone skin.
The benefits of a system like this are that the components can be interchanged and upgraded.
An entry-level foot or knee can be replaced with higher activity components when the amputee progresses to a higher activity level.
(Picture:Cosmetic spray on Super Skin) There is a huge selection of prosthetic knees and feet available in this day and age. Be assured that there are components available to fit any kind of activity level as well as most people’s pockets. I might at a later stage cover some of these components in detail.
My advice to the first time amputee is do not despair if you cannot afford the best. All components have to comply with industry standards. Less expensive components do not mean inferior quality, it might just limit you to certain activities but then again rehabilitation depends mostly on the patient and all components can be upgraded at a later stage.
This process will also ensure that you make full use of the functions of state of the art components if you get them at a later stage.
At the end of this article I would like to give a message to all amputees.
Losing a limb is not as big a problem as it used to be a few years ago.
Gone are the days of heavy wooden prosthesis’ suspended with bulky leather straps. Today donning and doffing prosthesis should be like wearing a shoe. (Picture: Back to life)
A patient should be able to do this in a matter of seconds.
A prosthesis can be custom made for most amputation levels and for almost any age patient.
But there is nothing I can do about an amputated soul. There is no prosthetic for that.
So remember, Amputation is the first step to rehabilitation!
You are not alone!