A team of biomechanical and bio-inspired technology engineers from Delft University of Technology, Netherlands, conducted a review to assess the available peer-reviewed literature on passive prosthetic hands and tools. In all, 38 papers were reviewed. The team found that passive prostheses receive little attention in the literature, yet they are shown to be useful to many people with unilateral upper-limb amputations. The review was published February 13 in Prosthetics and Orthotics International (POI).
The authors recommend implementing a classification of passive prostheses, as current literature uses ambiguous names for different types of passive devices. They propose that prosthetic hands and prosthetic tools be defined as static (cannot be moved at all) or adjustable (having an adjustable grasping mechanism or parts of the prosthesis can be adjusted to multiple orientations, which is typically accomplished by using the sound hand or pushing the prosthesis against an object). They also outline areas in which additional research and development should be conducted, among which are the following:
- Provide information on the characteristics of passive prostheses, such as hand opening, hand mass, and force required to open the hand, as these can be of value to rehabilitation specialists and users.
- Provide information on the dynamic appearance—a term relating to the movement of the prosthesis and the way activities are performed in relation to the sound hand—of passive prosthetic hands
- Future research should focus on the development of prostheses that offer limited, although sufficient, functionality for most activities of daily living (ADLs), instead of on increased functionality.
- Passive prosthetic hands are functional in many ADLS and should be offered as a serious option—along with active devices—and not mainly as a stepping stone to an active prosthesis, as a last resort, or just for improving appearance.
- The fingers of passive adjustable prosthetic hands could be made articulating, the grip force could be made adjustable, and the control of the opening and closing of the hand could be made faster and easier.
- To prevent users from frequently changing their prosthetic tool, it is preferred that the prosthetic tool (or hand) can be used for multiple activities.
- A passive adjustable hand that could grasp and hold a wide range of objects and be used for most ADLs would make single-activity-specific prosthetic tools unnecessary.
- Provide clear characteristics of prosthetic tools and prosthetic hands so users can make the best possible selection to fit their needs.