A prosthetic implant (Ancient Greek prosthesis ~ addition) is an artificial device that can be added to replace a body part, usually lost after trauma, aiming to ultimately restore the full function of said body part. The prosthetic limps can be hand-made or designed and generated through computer aided machinery using 3-D graphics. They are generally designed from lightweight materials in order for the amputee to control them easier/better. These materials include plastics (Polyethylene, Polypropylene, Acrylics), lightweight metals (Titanium or Aluminum) or even composites such as carbon fiber reinforced polymers [1].

Amputee rehabilitation is a lengthy and difficult process, primarily led by physiatrists and teams consisting of physiatrists, prosthetists, nurses, physical therapists, and occupational therapists. An example of the many challenges in this field is the neuroprosthetic hands. They are typically heavy (over 400 g) and οverly expensive (more than US$10,000), and lack the full compliance and tactile feedback of human hands.  Xiangyang Zhu at Shanghai Jiao Tong University in China and his colleagues developed a prosthetic hand that obeys the muscles’ commands for people with amputations below the elbow [2]. 

The individuals with a transradial amputation (the radius and ulna bones are cut) that wear the soft neuroprosthetic hand can regain primitive touch sensation and real-time control. Study participants needed just 15 minutes to learn how to control it, through pressure- sensitive sensors on the fingertips that send signals to electrodes attached on the upper arm.

The designed hand can grasp strawberries without crushing them and still works after being hit with a hammer or run over by a 1.5-tonne vehicle.

Additionally it is soft, low-cost and lightweight (292 g) and the components used cost less than $500. The hand is also considerably more lightweight than other available options, thanks to a bag worn at the waist that contains the battery and the electronics used to turn the arm’s signals into movement instructions [2]. 

This work could inspire the development of personalized, low cost neuroprosthetic hands for individuals with upper-limb amputations. Thus, the future seems promising for people with amputations.

Sources: [1] How artificial limb is made – material, manufacture, making, used, parts, components, structure, procedure”

              [2] Gu et al, ‘A soft neuroprosthetic hand providing simultaneous myoelectric control and tactile feedback’