The prostheses that are delivered to our clients are broken down into two groupings of prosthetic materials. The top of a prosthesis is a custom manufactured socket which is fabricated onsite within the APC prosthetic workshop. Moving downwards on the prosthesis is the second grouping of materials including structural components, prosthetic joints (i.e. hands/feet) and everyday consumables (i.e. liners/knee sleeves). These are always client-specific and ordered from a variety of prosthetic wholesale providers around the globe. Read below to find out further information on these materials used for prosthetics.
Materials used for Prosthetics
1. Prosthetic Sockets
To begin the journey of a definitive prosthesis, our clients are initially fit with a ‘Diagnostic Socket’ which is manufactured from their plaster cast. The primary aim of this socket is to optimise the socket fit, refine the alignment and ensure the prosthesis absolutely meets all necessary functional and comfort goals.
A diagnostic socket utilises materials in prosthetics which are suitable for a short-term trial period. These include thermoplastic sheets which are heat blistered and vacuumed onto the clients plaster cast. Following this step, the socket is attached to a lamination anchor which provides the connection between the custom-manufactured prosthetic socket and the remaining prosthetic componentry (ie. Prosthetic foot). To ensure safety and security, the anchor is secured to the socket. This can be done in a variety of ways from wrapping it in a fibreglass bandage, laminating carbon fibre or fibreglass over it. Once this is achieved, the diagnostic socket is ready for a short trialling period!
Utilising a rigid thermoplastic is beneficial in two ways. Firstly, it allows for reheating and adjustment so that pressure areas can be relieved. Secondly, the clear plastic allows the prosthetist to inspect the fit across the entire residual limb whilst the prosthesis is donned.
Once the prosthetic socket fit and alignment have been optimised, the diagnostic socket is ‘duplicated’ creating an identical plaster mould which allows our client to continue to wear their prosthesis whilst an APC technician concurrently manufactures their ‘definitive socket’. In addition, the duplication process allows for an identical alignment to likewise be captured which streamlines the definitive fitting process and removes the need for major alignment adjustments.
The materials used for prosthetics and the definitive socket vary considerably depending on the client’s presentation, suspension method and socket interface. Irrespective of these variables, all definitive sockets will undertake at least 2 separate laminations, they can manufacture with a single lamination however 2 is more common with varying amounts of prosthetic materials.
The plaster cast will be first either sealed with lacquer, a compressible liner, PETG or a flexible inner depending on what the prosthetist has deemed most suitable to the client. Next, a client-specific amount of carbon fibre, aramid fibre or fibreglass braid/matte is laid onto the socket and reinforced with unidirectional carbon fibre tape. It’s then sealed under vacuum with an acrylic resin which penetrates and solidifies the material. The initial lamination is focused on creating a strong, structured framework.
As the alignment has been duplicated in a jig transfer, the lamination anchor is attached in a similar process to diagnostic sockets. However, for the fabrication of the definitive socket, a great deal of detail and attention is paid to create a cosmetic appearance with the use of foam and putties.
The second lamination utilises similar materials to the first, however, its focus instead shifts towards strength and security of the lamination anchor to the socket. Importantly, each lamination is completely different because every client presents slightly differently in terms of, mobility, weight and intended activities (such as running).
Specialised Sockets (Design)
Many clients opt for a specific design to finish their prosthetic sockets ranging from Indigenous Art to sports teams – there is such a variety! Clients are encouraged to bring in fabrics, old t-shirts or designs which they desire on their final socket.
Specialised Sockets (Waterproof)
As an Island Nation with blistering summers, waterproof prostheses are essential! The lamination process is largely similar; however, it includes two additional laminations to finish with a cosmetic appearance which reflects the sound side limb. The APC technician precisely shapes foam around the socket according to the client’s measurements. This process removes the need for standard tube clamps and pylons which rust in water-based environments.
Specialised Sockets (Cosmetic Finish)
Similarly, to a waterproof prosthesis, a cosmetic finish utilises a foam which is shaped by an APC technician according to client measurements. Tracings of the sound side limb can be taken to ensure the prosthesis is as aesthetically appeasing as possible.
Specialised Sockets (Recreational)
The initiation of the National Disability Insurance Scheme (NDIS) has allowed many clients the opportunity to explore a recreational prosthesis such as running blades, rock climbing arms/legs, weight-lifting arms, surfing legs, cycling legs and many more. The custom design and materials used in prosthetics, allow for many recreational prostheses to be achieved.
Final and definitive prostheses reflect the great deal of detailed hours undertaken by both the prosthetist and technician to create custom-manufactured prosthetic sockets.
2. Prosthetic Componentry
Underneath the prosthetic socket is the second grouping of prosthetic materials – componentry. These are manufactured on a large scale by prosthetic wholesale companies across the globe producing materials in prosthetics such as feet/hands, connective componentry, pins/locks, valves, pylons, adaptors, liners etc.
Importantly, despite being mass-produced, the prosthetist orders componentry which specifically meet a client’s presentation, goals and intended activity. For example, one prosthetic foot may entail up to 10 different weight categories, it’s essential to obtain the current category for the client to ensure the best possible outcome.
- Wood, plastic, and foam are usually materials used in prosthetic feet designed for individuals who have low activity levels and require stability
- Carbon fibre feet is also one of the materials used in prosthetic feet designed to meet one’s functional needs for shock absorption and energy efficiency
II. Connective Componentry
- Aluminium, stainless steel, carbon and titanium are materials used in prosthetic connective componentry.
- Standard adapters are used to build the prosthesis, connecting the socket to a prosthetic joint and/or to a terminal device/foot.
- Functional adapters such as torsion and rotation adapters help make every day and/or recreational activities easier for patients by expanding the abilities of their prostheses.
For more information on materials used for prosthetics please get in contact with the team below!