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Active Knee Prosthesis Study for Improvement of Locomotion for Above Knee Amputees

The recruitment status of this study is unknown. The completion date has passed and the status has not been verified in more than two years.
Verified October 2008 by Providence VA Medical Center.
Recruitment status was:  Recruiting
Massachusetts Institute of Technology
Information provided by:
Providence VA Medical Center Identifier:
First received: October 8, 2008
Last updated: October 10, 2008
Last verified: October 2008

The purpose of this study is to develop a robust, low-power, stable, and light weight, active knee prosthetic device that can dramatically increase gait symmetry and walking economy of a transfemoral amputee during walking.

State of the art prosthetic knees can be classified into three main classes: a) mechanically passive, b) variable-damping, and c) powered. Although the devices within each of these classes offer some advantages for above-knee amputees, their overall performance still presents some deficiencies. Artificial knees in the first two groups are predominantly damping devices, incapable of providing positive power output. Moreover, current powered prostheses are heavy and inefficient in their energy consumption, and/or they have a limited range of motion. To overcome such inadequacies, we have designed a novel prosthetic knee device with a biomimetic approach.

The design of the active knee prosthesis is inspired by the antagonistic muscle anatomy of the human knee joint. This device mimics the synergistic muscle activity at the knee using a double series-elastic actuator (SEA) system that resembles the major mono-articular muscle groups that help flex and extend the knee joint. The agonist-antagonist SEA knee architecture will allow for precise force control of the knee joint, mimicking the spring-like behavior of the human knee, as well as providing adequate energy for forward progression of the body. The SEA has been previously developed and tested on legged robots. Also, the SEA has been successfully applied to the development of an actuated ankle-foot orthoses (AAFO) at MIT AI Lab.

The mechanical architecture of the active knee prosthesis allows for independent engagement of flexion and extension tendon-like, series springs for the control of joint position and impedance, as well as net joint torque. Furthermore, this architecture permits a joint rotation with near zero friction, allowing the controller to take advantage of the passive dynamics of the system, thus, augmenting the overall energetic efficiency of the system.

Condition Intervention
Device: Active Knee Prosthesis

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Diagnostic
Official Title: The Active Knee Prosthesis Will be Tested to Evaluate How Well it Improves the Gait Symmetry and Reduces the Metabolic Cost of an Amputee During Walking. The Prosthesis Will be Attached to the Socket of the Amputee.

Resource links provided by NLM:

Further study details as provided by Providence VA Medical Center:

Estimated Enrollment: 10
Study Start Date: May 2008
Estimated Study Completion Date: April 2009
Estimated Primary Completion Date: January 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Prosthesis
Motorized External Knee prosthesis for above knee amputees. Comprised of agonist and antagonist actuators to mimic behavior of knee joint during locomotion.
Device: Active Knee Prosthesis
Motorized External Knee Prosthesis for above knee amputees.
Other Name: Agonist Antagonist Knee Prosthesis

  Show Detailed Description


Ages Eligible for Study:   18 Years to 50 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • They will be experienced at prosthesis ambulation
  • Capacity of ambulation at least at a K3 level (i.e. having the ability or potential for ambulation with variable cadence).

Exclusion Criteria:

  • Amputee participants will be generally healthy and will have no other musculoskeletal problems or any known cardiovascular, pulmonary or neurological disorders.
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00771589

Contact: Hugh Herr, Ph,D 617 258 6574
Contact: Robert Emerson, CP 978-688-7900

United States, Massachusetts
Biomechatronics Research Group, MIT Recruiting
Cambridge, Massachusetts, United States, 02142
Contact: Hugh Herr, Ph.D.    617-258-6574   
Contact: Ernesto Martinez, S.M.    617 324 1316   
Principal Investigator: Hugh Herr, Ph.D.         
Sub-Investigator: Ernesto Martinez, S.M.         
Sub-Investigator: Grant Elliott, M.Eng.         
LIfestyle Prosthetics & Orthotics Recruiting
North Andover, Massachusetts, United States, 01845
Contact: Robert Emeson, CP    978-688-7900   
Sponsors and Collaborators
Providence VA Medical Center
Massachusetts Institute of Technology
Principal Investigator: Hugh Herr, Ph.D. Massachusetts Institute of Technology
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Hugh Herr, Ph.D., Massachusetts Institute of Technology Identifier: NCT00771589     History of Changes
Other Study ID Numbers: 0804002682
Study First Received: October 8, 2008
Last Updated: October 10, 2008 processed this record on April 21, 2017