Upper Limb Prosthetics – External-Powered Prosthesis for Partial Hand Presentation with the Thumb Intact

Christopher Lake, CPO, FAAOP
Margaret F. Wise, OTR, CHT, CVE
Advanced Arm Dynamics
Dallas, Texas

Limb deficiency distal to the wrist represents a common (1) and difficult level to treat with a functional prosthesis. Challenges include functional limitations of prosthetic technology, prosthetic interface discomfort, cosmetics and absence of tactile sensation. (2) Until the late 1990s, the lack of acceptable electric prosthetic options as well as concise treatment parameters have limited prosthetic treatment. (3) A new electric partial hand prosthesis design has been developed expanding on the earlier work of Biden and Bush at the University of New Brunswick in the late 1990s. (4,5)

An externally-powered prosthesis was designed for the individual presenting with loss of the fingers at the metacarpal-phalangeal (MCP) joint with thumb intact. See Figure. Fitting and therapeutic training protocols were developed specific to this level as none existed previously. Function and ease of use was compared between the electric prosthesis and a traditional passive prosthesis for two beta site patients. Standardized tests and functional tasks were utilized to compare the amputated side to the sound side. This type of testing was not applicable to the passive as no active motion of the prosthetic fingers is present.

The electric partial hand was preferred as a more functional option. This is due to the observation that the passive hand required pre-positioning of the fingers prior to many tasks. Since the electric partial hand did not require contralateral hand involvement to preposition the fingers and allows active movement of the first and second digits against the thumb, it was observed to allow more spontaneous function. Key to the success of this type of prosthetic management will be the fitting of the interface to allow unlimited wrist range of motion and detailed therapeutic program to increase the likelihood of integration of the prosthesis into everyday use. Initial results are promising and more definitive designs are currently under consideration.

  1. Dietal H. Hell C: The Otto Bock Transcarpal Hand Lecture & Beta Site Tests, 1999- 2001 Germany, USA, Canada.

  2. Wedderburn A. Caldwell RR. Sanderson ER, et al: A wrist-powered prosthesis for the partial hand. J Assoc Child Prosthetic Prosthetic Clinics 1986; 21:42-45.

  3. Lake C: Partial Hand Amputation: Prosthetic Management in Bowker and Michael (ed) Atlas of Limb Prosthetics, ed 3. St Louis MO, Mosby Year Book 2004.

  4. Biden E. Bush G: Recent Advances in the Development of Partial Hand Prostheses. MEC '97 Issues in Upper Limb Prosthetics, Journal of Proceedings – Institute of Biomedical Engineering, University of New Brunswick 1997.

  5. Discussions with Greg Bush, BA, CP(c)

Short Biographical Sketch of Authors


Chris Lake, CPO, LPO, FAAOP

Chris Lake is the South West Upper Extremity Specialist for Advanced Arm Dynamics (AAD) and has specialized in upper extremity prosthetics for seven years. Chris has published in Journal of Prosthetics and Orthotics and The Atlas of Limb Prosthetics. His Atlas chapter, "Partial Hand Amputations: Prosthetic Management," provides the foundation for his current research.

Margaret F. Wise, OTR, CHT, CVE

Margaret Wise is an occupational therapist, certified hand therapist with over thirty years of clinical practice in occupational therapy, including treating upper extremity amputees. She sees 15 to 20 new upper extremity amputees a year. She has presented numerous presentations in a variety of venues, including the New Brunswick Upper Limb Conference – MEC, 2002.