What Materials are Commonly used for Prosthetics?

What materials are commonly used for making prosthetics?

We get many questions about how prosthetic limbs are made. Below, we explain some of the different aspects and types of prosthetic limbs and what makes up each part.

How Are Prosthetic Limbs Made?

The prostheses (prosthetic limbs) that are delivered to our clients are made up of parts which can be grouped into three broad categories: Prosthetic Socket, Prosthetic Components, and Consumables.

The Prosthetic Socket is the upper part of the prosthesis which fits around your residual limb (AKA stump). This Socket is custom made onsite within the APC prosthetic workshop by our talented technicians. Below the socket are Prosthetic Components which include connective components (made of aluminium, stainless steel or titanium), prosthetic joints (such as prosthetic hips, knees, elbows and wrists), and prosthetic feet or prosthetic hands (also known as a terminal device). These Prosthetic Components are ordered from suppliers to meet each client’s specific requirements. Finally, consumables include items such as liners, knee sleeves, and socks which allow your prosthesis to comfortably hold on to your residual limb. These Consumables, like Prosthetic Components, are ordered specifically for each client, featuring materials such as silicone, TPE, rubber and much more.

Download our resources about how to care for your prosthesis and consumables. Or ask for our limb care guide at your nearest APC clinic.

Prosthetic Sockets

 

Diagnostic Socket Fabrication

The process of having a prosthetic socket made begins with your prosthetist taking a plaster cast of your residual limb. This is then filled with plaster to become a plaster copy of your residual limb (positive plaster cast) which can be used to make a Diagnostic Socket or a ‘check socket’. The primary aim of this clear plastic socket is to optimise the socket fit, refine the alignment, and ensure the prosthesis meets all necessary functional and comfort goals.

A diagnostic socket utilises materials which are suitable for a short-term trial period. These include thermoplastic sheets which are heat blistered and vacuum moulded onto the client’s positive 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. 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 trial!

Definitive Socket Fabrication

Once the prosthetic socket fit and alignment have been optimised, the diagnostic socket is ‘duplicated’ in an alignment jig creating an identical plaster mould whilst retaining the correct alignment of the connective componentry. Plaster or alginate is used in this step. If the shape of the socket allows it to be removed from the positive mould, the client can continue to wear their check socket whilst an APC manufactures their ‘definitive socket’.

The materials used in making definitive prosthetic limbs can vary. Factors include impact, weight of the user, activities that will be undertaken, method of suspension, socket design etc. Most definitive sockets will be made using at least two separate laminations, although some are made using a single lamination.

Some prosthetic socket designs will incorporate a compressible liner (typically made of a material called pelite), PET-G or a flexible plastic inner depending on what the prosthetist has deemed most suitable for the client. If your socket has one of these features, this is fabricated first on the inner most layer to the plaster cast. If not, the plaster cast will be first sealed with lacquer or similar (to prevent moisture leaving the plaster during the lamination).

      

Next an appropriate combination of materials including carbon fibre, fibreglass, stockinette, perlon and/or nyglass are layered over the cast, sealed under vacuum between PVA bags. Acrylic resin mixed with a hardener and sometimes a coloured pigment is then added. The resin penetrates the material fibres and solidifies the lay-up as the chemicals react, in a process called lamination. The initial lamination is focused on creating a strong, structured framework.

The lamination anchor (or adapter) is attached with bog in a similar process to diagnostic sockets but using the alignment transfer jig. The use of foam and putties allows for improved cosmesis and a smooth transition from the adapter to the socket. 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.

This layer can incorporate further coloured pigments or fabrics to personalise your prosthesis and show off your personality. We can laminate most materials as the final layer in the socket allowing endless cosmetic possibilities. 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, t-shirts, or designs which they desire on their final socket. Sometimes a third clear layer of resin is needed to ensure a quality cosmetic finish is achieved when customising with images.

 

Interim Socket Fabrication

Your first limb following amputation is known as an interim prosthesis. This is because it is only used for a short time, typically a period of a few months. Why such a short time? Following amputation, your residual limb will shrink and change shape as the muscles waste away (muscle atrophy).

An interim socket is intended to be used during this initial period of rapid muscle atrophy. The time frame to stabilising is different for everyone, as is the shape or how your muscles will change over time.

Interim sockets are made using similar prosthetic materials and methods as diagnostic sockets, for adjustability during the initial post amputation period.  Once residual limb volume has stabilised, a new cast will be taken so that a diagnostic socket and later definitive socket can be manufactured.

For more information, read our resources about the processes involved in being a new amputee, support services and amputee peer support

Specialised Sockets

Exoskeletal socket fabrication

           

For a more cosmetically shaped prosthesis, the socket can be laminated down to the foot or hand and shaped to closely match the shape of your sound side limb, this is known as an Exoskeletal Prosthesis (Exo for short!). This design removes the need for standard tube clamps and pylons (known as a modular or endoskeletal prosthesis). An exo design has a few extra steps involved.

Over the first lamination as above, the APC technician pours a two-part expanding foam around the socket on the transfer jig down to the adapter. Sometimes an aluminium or carbon puck is used, or in upper limb this is where the joint’s attachment site will be attached to the socket. Once the foam is hardened, the technician precisely carves the shape of the limb according to the client’s measurements of their sound side. Exoskeletal prosthetic sockets include two additional laminations to gain strength and finish with a cosmetic appearance.  This style of socket is commonly used for upper limb prostheses, and for waterproof prostheses. Some benefits of this design are that these prostheses are lightweight and have fewer components which might otherwise rust.

Recreational socket fabrication

     

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.

The final definitive prostheses for recreational limbs reflect the great deal of detailed hours undertaken by both the prosthetist and technician to create custom-manufactured prosthetic sockets. This follows the same steps as everyday and waterproof limbs, using similar materials and processes to laminate the socket.

If this is a part of your goals, or something that may interests you long term, make sure you talk to your prosthetist to include a recreational limb in your funding request. For more information about planning for NDIS and goals click to see our NDIS page.

For more information on materials used for prosthetics please get in contact with the team below

Lower Limb Amputation

Leg Amputation

Lower Limb and Leg Amputation is a life changing experience. Our APC Prosthetics team are here to help with every step of this journey. Our philosophy is to work with new amputees to comprehensively assess their needs, establish their requirements and deliver the appropriate solutions.

The first phase of the prosthetic rehabilitation process is what is known as an Interim Prosthesis. This process typically begins approximately 6 weeks after the leg amputation when the wound has sufficiently healed. Following the use of a stump shrinker (a specialised compression sock for amputees) to stabilise the limb, our prosthetic team will then go through the process of making a plaster cast of the residual limb, which is modified for each client to achieve a comfortable socket.

There are many methods of suspending a prosthesis to the limb and the prosthetist will select the most appropriate for the client/patient. The socket is attached with various connective componentry to a prosthetic foot. Like with suspension systems, there are hundreds of feet available, and the prosthetist will prescribe a prosthetic foot that best suits the ability, potential and goals of the patient.

When the interim prosthesis is ready, the client will return for their first prosthetic fitting where our team will assess the socket-fit and determine optimal alignment. It is expected that the residual limb will go through changes in shape and volume for the first months, which means the first prosthesis will undergo regular modification. For more information around lower limb amputation and leg amputation, please fill out the contact form below and one of our amazing team members will get in touch with you.

For more information on Lower Limb Prosthetics please read more here.

 

Young child receiving advice around leg amputation

 

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COVID-19 Requirements

As an essential service, APC Prosthetics services continue to be available and our clinics remain open. Please rest assure that our staff and clinics are implementing all State Government recommended hygiene and social distancing measures to ensure the absolute safety of all visitors.

We ask all of our clients to continue with their current treatment plans and current involvement with APC. Our primary focus is to ensure the health and well-being of our staff and our clients. The following COVID-19 regulations will be enforced at our clinics:

  • All clients and their carer must check-in using the QR code.
  • A limit of 1 carer per client to minimise the number of people in our clinics.
  • Masks are to be worn upon entering any APC clinic and for the duration of the appointment.
  • Hand sanitise at entry, we have sanitisers readily available at reception.

If you are experiencing any cold/flu like symptoms, have visited any of the COVID-19 exposure sites, or need to follow self-isolation protocols, please contact our administration/reception team to discuss the deferment of your treatment.

We will continue to monitor the situation closely and keep our clients and partners updated. Please follow us on Facebook and Instagram for the latest updates.

The team at APC are committed to the care of the local amputee community. Thank you for your cooperation and we will do our best to meet your needs during this time. If you have any concerns or queries, please do not hesitate to contact us.

Prosthetic Knees

Prosthetic knees have had some impressive technological enhancements in previous decades and continue to do so. These improvements have helped enhance the functionality and safety of prosthetic knees. Most notably in these improvements is Microprocessor controlled knees (MPK’s). Other mechanical knees use the integration of hydraulic and pneumatic features which allows the knee units to adapt better to real-life situations and environmental changes which is imperative when walking on slopes, stairs, and uneven ground etc.

Single Axis and Multi-Axis Knees

The primary difference between prosthetic knees is whether they are single or multi-axial, which means they have a single hinge point or at multiple hinge points. Single Axis is the most common prosthetic knee joint. The majority of microprocessor knees as single axis. Multi axial knees (polycentric knees) can shorten the prosthesis when in swing, reducing the risk of tripping and falling. Polycentric knee units can meet the needs of various users from low to high activity. These are also a good option for people with long residual limbs, so the prosthetic knee does not stick our further than the sound side in sitting.

Some of our designs such as our recreational limb was put together for a client that has dreams about hitting the slopes and waves with their prosthesis.

Controlling a Prosthetic Knee

Prosthetic knees use a variety of strategies to control the way the knee behaves. Pneumatic knees use air to adapt their function such as when walking at different walking speeds. Hydraulic knees use fluid to adapt their function. Other varieties can utilise a combination of springs, friction and/or locks to control the function of the knee in a more basic way.

Not all knees use microprocessors and sensors to vary their function. These rely solely on alignment and the user to ensure the knee works correctly at different stages of walking.

Microprocessor Controlled Knees 

prosthetic knee

MPK’s use a computer and input from various sensors to continually change and optimise the knee function. These technological inclusions allow the knee to better adapt to real-life situations and environmental changes, allowing improved safety and function. Additionally, MPK’s have intuitive functions for going up and own stairs and ramps. MPKs can be programmed to specific activities such as cycling and running. Microprocessor knees can be heavier than mechanical knees and require charging. 

MPK’s are a great prosthetic knee for the appropriate person but are not appropriate for all users. Your prosthetist will work closely with you to find the most appropriate prosthetic knee based on your level of amputation, functional capabilities, goals, and activities that you enjoy. 

Along with the enhancements with prosthetic knees, there is now a variety of socket design styles, suspension methods, prosthetic feet. 

 

Prosthetic Fingers

The objectives in upper limb prosthetics is to meet the requirements for our clients work, lifestyle and recreational needs of each amputee in order to reach a pleasing outcome. Technological advancements over the decades  have been made in body powered prostheses, external powered prostheses, hybrid systems and the sockets & interface. Improvements made with upper limb prosthetics, specifically in myoelectric units has vastly increased the opportunities and possibilities for prothesis such as Prosthetic Fingers.

Body Powered Prosthesis

The most common type is the Body powered Prostheses. They allow their prosthetic user to control the terminal device (that being a hook, hand or prosthetic fingers) that fits around the users shoulder or chest via a harness. The body powered prosthesis is reliable, durable and can be used for places where dust and water are present though some have found it cumbersome and uncomfortable.

Externally Powered Prosthesis

Externally powered prostheses use a battery powered electric motor to control the terminal device, which removes the need for a harness. The sensors that are implanted in the socket, picks up an EMG signal on the skin and sends that signal to a processor which controls the functions of the motor. The motor then powers the elbow/wrist or terminal devices. Training with your prosthetist and occupational therapist along with the training apps which is essential to have a successful outcome. The apps available with the myo-electric have the option of allowing for custom movements or settings for specific movements that fit your needs in most cases. To be considered for a candidate for a Myo-electric there must be enough viable muscle sites.

Hybrid Systems

Hybrid Systems are a combination of externally and body powered prostheses. This specific type of prosthetics can be used for Trans-humeral (above-elbow) amputees. By allowing restoration of elbow and hand this has allowed one of our clients to get back on his motorbike. The elbow joint is controlled via a harness system and the hand or hook is controlled through an external power source such as myo-electrically.

Upper limb prosthetics is a highly customised process in not only the prosthesis itself but for the socket design as well. Being highly customisable allows the socket for your upper limb and prosthetic fingers not only for adults but for our paediatric clients as well. To find out more about our Upper Limb Prosthetics click here.

Prosthetic Fingers

 

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Prosthetic Foot

Prosthetic Foot & Ankle

The human foot-ankle is a very complex functional unit. It provides stability as well as flexibility and utilises muscle to generate energy for efficient and comfortable walking. Through the improvements and advancements in the making of the prosthetic foot made to the design and manufacturing of prosthetic feet. These improvements allow for much more energy efficient and improvements in walking.

Each client is unique and every one of them has different needs and lifestyles as it is vital to choose the most appropriate prosthetic foot to achieve maximum comfort and function. Material used in this prosthetic is lighter and more durable which results in an improved comfort and function. Not only just making prosthetic feet but the customisation of amputee fins for those clients who have a passion for getting into the water and swimming or surfing for example. To find out more about our Lower Limb Prosthetics click here.

prosthetic foot

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The Journey of A Refugee

In honour of World Refugee Day, we’re celebrating the strength and courage of one of our very own Prosthetic Technician, Samer Zakhour, and one of our clients, Linda. They share their story as refugees from Syria, and how being at the same place at the same time allowed them to reconnect years later in Australia.

Samer first met Linda in Syria as her prosthetist, treating her through the Syrian civil war. They both dreamt of a new life, searching for safety and a better future for their families away from the war. Although they lived separate lives and had their own families, their experience arriving to Australia in 2016 were quite similar. Learning to live and adapt to life in a different country was a big challenge. From learning English to learning to do an everyday activity like catching a bus, everything felt like a new experience.

When Samer first arrived in Australia, he found a place to live and shortly after started a TAFE course. How comforting it was to see Linda, a familiar face in a completely new environment. Here, they sat at the same table, in the same class and reconnected. They were grateful for the opportunity to study and learn English, see their families happy, play the sports they enjoy and live a life they dreamed of.

Linda invited Samer to attend her next appointment at APC. It was on this day that Samer was introduced to the APC Team, showing his portfolio and discussing his passion for the industry having worked in Syria as a Prosthetic Technician for more than 13 years. The familiar smell of resin in the workshop felt like home to Samer. It was through these series of events that he was offered a 3-month contract at APC, which very quickly turned into a full-time permanent role. APC is proud to have Samer as part of the Team, he takes great pride in all his work and loves to see the smile on his client’s faces when they receive their new prosthesis.

Today, Samer enjoys his new adventures and freedom in Australia. He loves to go camping with his kids and is enjoying his hobbies like playing the pan flute and drums. Linda was able to receive a prosthetic arm with government assistance. She’s currently a stay-at-home mum of 2 daughters, loves spending time with her family, and attends church where she enjoys organising the choir.

Both Sam and Linda will test to get their citizenships later this year. They feel like true Australians and are grateful to call Australia their home.

Care for your Skin

How to clean your residual limb

Being a new amputee now requires you to take care of the skin on your residual limb. We have created a simple 3 step process that shows how to best clean your residual limb. A combination of washing the limb with soap and moisturising the limb regularly will not only make it easier to wear your prosthesis, but will also reduce the frequency of rashes, bacterial infections etc., from appearing on your residual limb. For more information about other skin issues, please download the Residual limb care guide at the bottom of the page.

Step 1: Wash with a mild soap (pH = less than 7)

Step 2: Moisturise after wash to prevent dryness. Only apply moisturiser in the evening.

Tip: If you are a new amputee or have high volume fluctuations in your limb, it’s recommended to shower at night. The heat of the shower and your limb hanging down can make it harder to don your prosthesis in the morning when most users experience their highest volume of the day already. Give it a go!

Care for your Prosthesis

Upper Limb (UL) users: Your socket should be cleaned weekly. You should regularly clean the hand and/or cosmetic glove.

Transtibial (BK) users: Your socket should be cleaned weekly.

Transfemoral (AK) Users: Your socket should be cleaned daily.

 

How to clean your socket & components

When cleaning your socket, wipe your socket with a damp cloth and a mild detergent and dry it thoroughly before you put it back on. It is not necessary to use an antiseptic to clean your socket.

Tip: Never use Dettol or other solvents to clean your socket or liner.

 

Wet/Dirty Prosthesis: It’s important to clean the components as well as the socket. Tip your prosthesis upside down to empty any water out of the foot shell. Use a shoe horn to lever off the foot shell. Remove, clean and dry the spectra sock (nylon sock between the foot shell and carbon fibre foot). Rinse out and dry the foot shell. Put the spectra sock back over the carbon fibre foot and use a shoe horn to reattach the foot shell.

 

Cosmetic Cover: If you have a cosmetic cover, it is important to keep this clean as well. A hard cover can generally be cleaned in the same manner as your socket. A soft/foam cover with stockings – you can wash the stockings as you would any hosiery/delicates. Wipe the foam with a slightly damp cloth and allow to dry before redonning the stockings.

Tip: Remember, keeping your prosthesis clean and drying after getting wet is crucial for maintaining longevity of the components and preventing rust or damage.

NDIS Participants Guide To Your Planning Meeting

Your planning meeting is where you discuss your functional goals and any funding requirements you require for the life of your next NDIS Plan.

Prior to meeting with your NDIS Local Area Co-ordinator (LAC), we recommend our participants contact our NDIS Administration Staff at APC Prosthetics to discuss your requirements, so they can assist in formulating the finer details for discussion with your Local Area Co-ordinator at your meeting.

 

Key points to discuss during your initial planning meeting

  1. Provision for Maintenance: this includes the cost of maintenance to your current limb. Please note an assessment, quotation and Assistive Technology Request is required by NDIS. This cost should be included under Capacity Building (CB) Daily Activity, please account 4-6 hours for the report and 8 hours for maintenance.
  2. Provision for Capital Supports/Assistive Technology: this will include the funding for your prostheses. Please note these items need to be quoted and approved through the Assistive Technology approval process.
  3. Provision for Core Supports: this includes ongoing low-cost consumables related to your prostheses, such as socks and sprays. Please note higher cost consumables need to be quoted and approved.

 

We recommend requesting for your NDIS Local Area Co-ordinator’s phone number and email address, so we can communicate with them directly if you require us to do so.

If you would like to have a chat about the NDIS and how we can help you prepare for your planning meeting, please contact your local APC NDIS Coordinator.

 

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