Providing upper-extremity prosthetic device users with functionality and flexibility

Posted January 26, 2016
Harold H. Sears, Ph.D., Motion Control, Inc.

Existing prosthetic terminal devices, such as hands and wrists, have limited capability for manual work activities due to complex construction, restricted range of motion and force, and coverings which can tear and stain. Although much progress has been seen in the last decades on sophisticated control, and human-like appearance, a prosthesis that incorporates reliability in heavy duty work environments with sophisticated control and aesthetic appeal has been difficult to achieve. However, such characteristics will help upper-limb amputees, especially soldiers, to return to their former work lifestyles.

With funding from an FY09 PRORP Technology Development Award, Motion Control, (PI, Dr. Harold H. Sears) is working to advance the design and capabilities of the Electric Terminal Device (ETD), an existing "hook-type" prosthetic device provided by Motion Control since 2005. For many patients in U.S. military hospitals the ETD is the first choice hand replacement for function and versatility. Additionally, the ETD is the only upper-extremity prosthetic device that achieves true resistance against water, dirt, dust, and grease, and therefore allows amputees the flexibility to wear it in diverse work and recreation environments. Motion Control upgraded the existing ETD by coupling a shorter and lighter forearm section with a series of modular wrist joints. As wrists represent a key component in the performance of terminal prosthetic devices, the modular wrists have been designed to vary in complexity and offer both electronic and manual control of wrist position. The modular wrists will be interchangeable and compatible with existing arm prosthetics, since a new quick disconnect system is part of the device design. The innovations accomplished by Dr. Sears and his team will preserve the rugged dependability of the existing ETD, while improving range of motion, gripping security, and aesthetic appeal for its wearers.

Prototypes of the second-generation ETD (ETD2 is the working title) have entered field trials, and are used daily by several individuals with upper-limb loss. The interchangeable components of the ETD2 will allow for personalized prosthetics based on injury and individual lifestyle needs. This development project will significantly improve an existing prosthetic system to benefit permanently disabled Service members, Veterans, and civilians with upper-extremity loss. The practical goal is to enhance their functionality and promote return to work settings of all types. Recent follow-on funding awarded to Motion Control from the Joint Warfighter Medical Research Program will support the development of a similarly ultra-rugged elbow system, further leveraging the devices generated in this highly successful project.

Links:

Public and Technical Abstracts: A New Powered Flexion Wrist and Modular Prosthesis System

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