Prosthetic limb options provide amputees an extensive variety of choices in terms of work and purpose.
How do prosthetics work?
Artificial limbs or prosthetics allow amputees to recapture function resulting from the absence or loss of a limb. Prosthetic limbs are categorized according to the level of amputation: below the knee, above the knee, below the elbow, and above the elbow. Priority in terms of prosthetic use and selection is often based on considerations for aesthetic, functionality and or health concerns.
For leg amputees particularly, prosthetics can be crucial for mobility and the prevention of muscle atrophy, spinal curvature and trunk instability depending on their level of amputation. For few arm amputees, aesthetic may be a decisive factor due to the social usage and increased visibility of the hands. Irrespective of the motivation for using a prosthetic, prostheses are a vital part of the lives of many amputees. Developments in technology have brought about in a wide range of prosthetic options to address the different needs of amputees.
How do prosthetic hands and legs work?
Prosthetic limbs work differently according to the desires and needs of the amputee. Amputees can go for prosthetic limbs that only provide a cosmetic purpose, that are fastened by belts or harnesses, that are worn using sockets with suction systems, or that are even surgically embedded.
Few amputees, mostly upper extremity amputees, may often opt to use a passive prosthetic, which has a little function other than having a natural exterior. These are usually very lightweight, which means they need less effort and energy for sports. Passive prosthetics in some examples have joints that may be moved into changing positions to allow the person to move or stabilize objects. Prosthetic fingers and prosthetic toes can also be made for cosmetic purposes in the case of absence or loss of the digits.
Another choice for arm amputees is the body-powered prosthesis. This comprises of cables and a harness that is maneuvered by the shoulders, chest, or remaining part of the arm tied to the level of amputation. The cables and harness allow for closing, opening and sometimes rotation of a terminal device (hook or hand) depending on the outline of the prosthetic arm. These are a popular pick for people who want durable prosthetics that permit them to engage in different types of labor.
Technological advances have also developed myoelectric prosthetics. Myoelectric arms and hands are controlled by connecting sensors to detect electrical impulses from present muscles. The speed, strength, and direction of movement are managed by the intensity of the signals from the muscles. For people without arms, or with nerve or muscle damage, the back or chest muscles can be used. Myoelectric prostheses are battery run and thus must be charged.
They are put on using a custom socket that is pulled on using a sock which generates enough suction to attach the limb. These prosthetics can be used with a range of terminal devices. Some people choose covers that can be matched to skin color and look like natural hands, others may opt for terminal devices that have a simpler gripping function, and others choose to use the hands without covers. There are also myoelectric prosthesis and hybrid body-powered that can be used for higher amputation levels or differing degrees of functionality.
Moreover, there are function-specific prosthetic arms that have a range of attachments based on the intended usage. These are usually used in sports, work activities and hobbies.
For lower extremity amputees, prosthetics can permit the option of mobility beyond a wheelchair or crutches. A prosthetic leg is fixed based on the outline of the person’s residual limb. A frame of the residual limb is made in order to make a socket that works as the point of attachment. Socket fit is very vital because a good fit is essential for functionality. Otherwise, skin damage, friction swelling and discomfort may prevent the limb from working or being used properly.
Under the knee amputees have a socket that extends to a foot and a pylon. Prosthetic feet can have microprocessors or be hydraulic depending on the kind of land that the person desires to walk on and the pursuits they want to join in. There are also activity-based feet, for instance, the blades that few athletes use for running.
Above the knee amputees can select from a variety of options in terms of knee selection. Prosthetic knees can have multiple or single-axis systems, muscle controlled or weight-activated stability, and lastly, there are microprocessor knees that permit a more controlled, natural walk that requires less effort. All amputees apply more energy when walking – oxygen consumption can rise by up to 20% for a below the knee amputee, up till 70% for an above the knee amputee and up till 300% for a bilateral amputee. For these grounds, prosthetic selection (or even the selection to use prosthetics or not) is a careful decision that also involves gait training, many socket fittings, and occasionally physical and occupational therapy.
What are prosthetics made of?
Besides the labor-intensive procedure on the part of the amputee, orthoptists and prosthetists also have quite the task in creating prosthetic limbs that work for the changing needs of their clients. Prosthetics should be durable, lightweight and easily attached to the body.
The raw materials used in making prosthetics are usually different types of plastics, including polyethylene, acrylics, polypropylene and polyurethane. Lightweight metals such as titanium and aluminum are also used. Moreover, some prosthetics are made from carbon fiber. Electronic prosthetics usually require batteries that must be charged. Few also have Bluetooth capabilities and can be synced with cell phones.
Several leg amputees wear silicone liners between their residual limb and their sockets. Sockets must be tested over time for fit and comfort, and thus are usually made from thermoplastics that can be heated and reshaped during the alteration phase. When the test socket is ultimately up to the desired standard, plastic is usually used to make the final socket. The pylon for an artificial leg is usually made from lightweight metals or carbon fiber, which is more weightless than the metals.
Prosthetic limbs are usually balanced using suction systems or by harness depending on the level of amputation and kind of prosthetic. For many prosthetic legs and arms, the suction of the socket may also be enhanced or aided by a sleeve or sock that helps with fit and skin protection. For body-powered prosthetic arm design, harnesses can comprise of leather, connected to cables which move the arm using springs and controls the hooks which are usually made of stainless steel.
The Future of Prosthetic Limbs
Because of the intricacy and variety of materials, as well as the toil that goes into making prosthetics, they can be quite costly. Almost 30 million amputees live in developing countries where the average income level would make attaining a prosthetic limb nearly impractical. Learning to use a prosthetic also takes a substantial amount of time and training, which can also lead to barriers to access. Although the adjustment period in using a prosthetic is unescapable, organizations and companies around the world are beginning to use 3D printing for prosthetics to eliminate the barrier of cost.