Prosthesis

A prosthesis (pl.: prostheses) is an artificial device that replaces a missing body part. This can happen when someone loses a limb or other body part due to physical trauma, disease, or a condition they were born with, known as a congenital disorder. Prostheses help people do everyday things or simply look like they did before.

People who have had to have a body part removed are called amputees. Special doctors called physiatrists work with teams of experts to help these individuals recover. This team includes prosthetists who make the prostheses, nurses, physical therapists, and occupational therapists.

Creating a prosthesis can be done by hand or with the help of computers using something called computer-aided design (CAD). This software lets experts design and test their creations using special 2-D and 3-D graphics, making sure everything works just right before it is built.

Types

A prosthetic device helps replace a missing body part. It can help with looking normal and doing things. People choose prosthetics based on what they need, how much money they have, and where they can get care. Prosthetics can be for the face, neck, torso, or limbs.

Limb prostheses replace arms or legs. Upper limb prostheses can be passive (for looks), body-powered (using muscles), or myoelectric (using batteries and sensors). Lower limb prostheses replace legs at different levels. New designs use special materials and technology to help people walk more easily. Prosthetists make and fit these devices, and physical therapists help people learn to use them.

History

Prosthetics have been used for a very long time, dating back to ancient times. The oldest examples come from around 3000 BCE in ancient Egypt and Iran. People there made simple artificial body parts, like wooden toes or eye coverings.

Many famous people in history used prosthetics. A Greek story talks about Hegesistratus, who wore a wooden foot. In ancient Rome, Marcus Sergius had an iron hand to help him hold his shield in battles. During the Middle Ages, knights sometimes used basic prosthetics to help them hold weapons.

Over time, prosthetics got better. By the 1500s, people made them from iron, steel, copper, and wood. Inventors like Ambroise Paré created new designs to help people walk and do everyday things. In the 1900s, new technologies like microprocessor-controlled knees helped make walking with a prosthesis feel more natural.

Today, prosthetics keep getting better. They use lighter materials like carbon fiber and new technologies such as bionic limbs. These modern prosthetics can copy natural movements and help users feel more confident and independent.

Patient procedure

A prosthesis is a special replacement for a limb that is missing. This can happen if a limb was lost in an accident or if it did not grow correctly from birth. Prosthetists are the experts who make and manage these devices. They often start by making a mold of the patient's remaining limb. Then they build a custom-made prosthetic using strong, light materials like carbon fiber and titanium. Some advanced prostheses have special electronics to help them work better.

Current technology and manufacturing

Artificial limbs have become better over time with new materials like carbon fiber. These materials make limbs stronger and lighter, helping people walk more easily. They also look more like real limbs, which many people prefer.

Electronics are now important in artificial limbs. Some limbs use muscle movements to work, called myoelectric limbs. Computers help make and design these limbs. Most modern limbs attach to the person’s remaining leg or arm using belts, cuffs, or suction. The limb fits into a socket, often with a soft liner to make it more comfortable.

Making a prosthetic socket starts by getting the shape of the remaining limb. This can be done with a plaster cast or digital scanning. The socket is made to fit this shape perfectly, so it feels comfortable and stays in place.

Making an artificial limb has several steps: measuring the limb, creating a model, fitting a liner, forming a thermoplastic sheet, making the socket, and putting the limb together. Some limbs move with the person’s body, while others use electronics.

For lower-body prosthetics, there are two main types: those for legs above the knee (trans-femoral) and those for legs below the knee (trans-tibial). The socket is important because it connects the limb to the person’s body. The foot of the prosthetic helps the person walk smoothly, and the knee joint in above-knee prosthetics helps the person bend their leg naturally.

Some modern knee joints use small computers to help the limb move more like a natural knee. Myoelectric prostheses use muscle signals to control the limb. Robotic prostheses are being developed to help people control their limbs even better. These use sensors and computers to turn brain signals into movement.

Prosthetics are also being made from recycled materials, like plastic bottles, to help protect the environment.

Direct bone attachment and osseointegration

Main article: Osseointegration

Most prostheses are attached to the outside of the body, but this can be uncomfortable. Direct bone attachment is a way to connect an artificial limb more closely to the body. This method uses a special implant made of titanium that is placed into the bone where the limb is missing. Over time, the bone grows around the implant, creating a strong bond. After this, a small part called an abutment is added, allowing the artificial limb to be attached securely.

This method helps people have better control over their prosthetic and wear it for longer periods. However, it does have limits, such as avoiding high-impact activities to protect the bone.

Cosmesis

Cosmetic prostheses help cover injuries or make a missing limb look more natural. We can make very lifelike artificial limbs using materials like silicone or PVC. These prosthetics can look just like real hands, with details such as freckles and veins. Custom-made versions are very detailed but cost a lot of money. Standard versions come in different sizes but are usually not as realistic. There are also silicone covers that match a person's skin tone. These cosmetic prostheses can be attached to the body in several ways, such as using adhesive, suction, or special stretchable material.

Cognition

Main article: Neuroprosthetics

Neurocognitive prostheses are devices that might help the brain with tasks like focusing, remembering, and using language. They are not available yet, but scientists are working on them. These devices could help people with conditions such as stroke, traumatic brain injury, cerebral palsy, autism, and Alzheimer's disease. Some tools, like reminder devices, already help people remember important tasks, and other small devices guide people through daily activities.

Prosthetic enhancement

Further information: Powered exoskeleton § Research

Beyond everyday artificial limbs, special devices help people who have lost a limb or were born without one to join in sports and fun activities.

In stories and real science, people imagine using very advanced artificial parts to do even more amazing things. Famous thinkers and scientists discuss if this is right or good. For example, in 2002, a scientist named Kevin Warwick had a tiny device put into his body so a robot could move just like his real arm.

Some companies create very smart artificial arms that work with the brain, like the “Luke arm.” Testing began in 2008, and it was approved for use in 2014. Scientists continue to find new ways to make artificial parts fit better and feel more natural.

Design considerations

When making a transtibial prosthesis, there are important things to think about so it works well for the user. We need to think about how well it fits, how it helps with movement, how it stays steady, and how easy it is to use. We also think about how it looks, how much it costs, and if it comes in different sizes.

It is important to include people with disabilities when designing prosthetics. This means working together with them to make sure the designs are good for their needs. This helps make better prosthetics that help users every day.

Cost and source freedom

The cost of a prosthetic limb can be different in different countries. In the United States, a typical prosthetic limb can cost a lot of money. With insurance, patients usually pay some of the cost.

In places like the United Kingdom, Europe, Australia, and New Zealand, the government or insurance often pays for the full cost.

There are also lower-cost options. Some organizations make basic prosthetic devices for places that need them. With new technology like 3D printing, it is now possible to make affordable prosthetics. One example is the "Hero Arm" made by Open Bionics. It uses 3D printing to create personalized prosthetic hands at a lower cost. These new ways of making prosthetics aim to help everyone get the help they need.

Main article: 3D Printed Prosthesis

See also: 3D printing, Open-source hardware, Modular design, Thingiverse, and Open Bionics

Low-cost prosthetics for children

See also: open-source hardware and 3D printing

Many children lose a limb because of illness, injury, or how they were born. In some places, getting a prosthetic limb can cost a lot of money. So, special low-cost solutions have been made to help these children. These solutions use simple materials that are easy to find nearby, and they can be very helpful.

Some examples of low-cost prosthetic devices include a hand-held pole with a leather support, limbs made from bamboo, PVC, or plaster, an adjustable limb made from a bicycle seat post, the Sathi Limb from India made with thermoplastic parts, and Monolimbs which are strong but need careful fitting. These options help children move and play more comfortably.

Cultural and social theory perspectives

Some thinkers think about what it means for people to use artificial body parts. They ask if prostheses fix something that is missing or if they help us do new and exciting things. These ideas connect to how we understand our bodies and the world.

Prostheses can change how people feel about themselves and how others see them. For someone who has lost a limb, using a prosthesis can help them feel more confident. However, losing a limb can be very hard and may cause feelings of sadness.

There are also questions about how prostheses are made and tested. Some concerns are about whether patients understand what they are agreeing to when trying new devices.

There are also debates in the prosthetic community about whether to use a prosthesis. Some people feel they can manage without one, while others find them helpful. Every person’s choice about using a prosthesis is respected.

Notable users of prosthetic devices

Some famous people have used prosthetic devices. Henry William Paget, 1st Marquess of Anglesey lost his leg in a battle and used a prosthesis afterward. Marie Moentmann, a child who survived an accident, also used a prosthetic device. Terry Fox was a Canadian athlete and humanitarian who became famous for his cancer research activism. Oscar Pistorius, a South African sprinter, used prosthetics to run professionally. Harold Russell, a veteran of World War II, won an Academy Award for his acting and was known for using a prosthetic arm.

Mythological

In old stories, heroes sometimes lost body parts in battles. They were given special replacements to help them. For example, Nuada, a mythical king, lost his arm in battle and was given a silver arm. Visphala, mentioned in the Rigveda, lost a leg in battle and was given a leg made of iron.