The “Fluidhand” from Karlsruhe, Germany is an innovative prosthetic prototype being tested in the Orthopedic University Hospital in Heidelberg. Unlike its predecessors, the Fluidhand can close around objects, even those with irregular surfaces. A large contact surface and soft, passive form elements greatly reduce the gripping power required to hold onto such an object. According to the developers, the hand feels softer, more elastic, and more natural than conventional hard prosthetic devices.
Flexible drives are located directly in the movable finger joints and operate on the biological principle of the spider leg – to flex the joints, elastic chambers are pumped up by miniature hydraulics. In this way, index finger, middle finger and thumb can be moved independently. The prosthetic hand gives the residual limb feedback, enabling the amputee to sense the strength of the grip.
Thus far, 18-year-old Sören Wolf has been the only patient at the Orthopedic University Hospital in Heidelberg who has tested both the i-LIMB hand and the Fluidhand. “This experience is very important for us,” said Simon Steffen, director of the Department of Upper Extremities at the Orthopedic University Hospital in Heidelberg. Developers said of the two models tested, the Fluidhand held a slight advantage because of its better finishing, the programmed grip configurations, power feedback, and the more easily adjustable controls.
The costs of manufacturing the device are comparatively high. “First the developers have to find a company to produce it,” said Alfons Fuchs, director of Orthopedics Engineering at the Orthopedic University Hospital in Heidelberg. However, it is possible to produce an individual model. Only one patient has received a Fluidhand for everyday use, while a second patient in Heidelberg will soon be fitted with this innovative prosthesis.