Handcrafted Prostheses - Wacker Chemie AG


Handcrafted Prostheses

Silicone elastomers from WACKER can be used to make lifelike reproductions of amputated limbs. This craft has been perfected by the German manufacturer Ottobock, whose silicone limbs help patients to enjoy a better quality of life.

For the prostheses to look as natural as possible, they are available in every skin tone imaginable. To do so, the silicone is not uniformly colored. Ottobock technicians incorporate viscose flocks, chopped threads and some other tricks to provide a degree of three-dimensionality.

The fingers are slender and delicate. Tendons and veins seem to shimmer through the back of the hand. Janine Grützmann applies another extremely thin layer of slightly reddish silicone so as to get an even closer match for the coloring of the joints. Every year, hundreds of such deceptively realistic hands, feet, fingers and toes are artistically crafted from WACKER silicone at Ottobock, a prosthesis maker in Duderstadt (Lower Saxony, Germany). This group with around 5,000 employees produces more than prostheses, however – it also makes orthopedic articles and wheelchairs. Furthermore, it is one of the main sponsors of the Paralympics – the Olympic Games for physically-disabled athletes.

Craft and Art

Every week, Grützmann, a qualified dental technician, models two to three hands from the dough-like silicone. It is a craft that was developed in 1995 by a Belgian dental technician and for which there is no special training. Grützmann learned it on the job at Ottobock – step by step. “I was assigned to work on individual fingers, before graduating to hands and then, at some point, to whole arms.” The first step in making a prosthesis is to take an impression of both the stump and of the patient’s intact hand. Then a lump of flesh-colored silicone rubber compound is placed on the stump and a copy of the intact hand is modeled. “You cut off what you don’t need,” says the Otto Bock employee, “until the fingers and palm gradually take shape.”

“We use the material’s translucency to mimic the skin’s light permeability.”

Andreas Leiniger Head of the Silicone department at Ottobock
  • In the cleanroom, WACKER employee Franz Damoser checks the silicone rubber block before it is sent to the customer.

  • In the cleanroom, WACKER employee Franz Damoser checks the silicone rubber block before it is sent to the customer.

  • At the Ottobock workshop, the silicone block is first rolled out flat (above photo series, from left).

  • Then, the individual color components are exactly calibrated and applied to the as-yet colorless silicone.

  • Then, the individual color components are exactly calibrated and applied to the as-yet colorless silicone.

  • All components are then mixed on the roller until the silicone slab has attained the previously defined skin tone (photo series below, from left).