Evaluation of High-Performance, Customized, Rapidly-Manufacturable Prosthetic Feet That Provide Improved Mobility

Study Overview
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Brief Summary
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The purpose of this research is to design a high-performance, customized, and rapidly- manufacturable passive prosthetic foot for use in the United States. We are currently testing an early stage prototype and would like user input before pursuing additional clinical testing. Participants will be asked about their current prosthesis type and use, amputation side and cause, and activity level. We will take measurements of height, weight, and length of the participant's residual limb. The participant will be asked to walk in several prosthetic foot conditions in multiple walking activities, and the visit should last approximately four hours. For each prosthetic foot, a trained prosthetist will fit the foot (either a prototype foot or a commercially available K3/K4 foot) to the prosthesis. The patient will then walk around the room until they feel comfortable. They may initially walk using a gait belt or between parallel bars based on comfort level and an evaluation by the prosthetist. Once they feel comfortable walking on level ground at a normal speed and the prosthetist feels that they will be safe performing more challenging walking activities, the participant will perform different walking activities (such as walking on flat ground at different speeds, walking up/down ramps, and walking up/down stairs). They will then be asked to tell the investigator what they like and dislike about the prosthetic foot.

Detailed Description
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The purpose of this research is to design a high-performance, customized, and rapidly- manufacturable passive prosthetic foot for use in the United States. We are currently testing an early stage prototype and would like your input before pursuing additional clinical testing. The Global Engineering and Research (GEAR) Laboratory at the Massachusetts Institute of Technology (MIT) has developed a novel design framework for creating high-performance, passive prosthetic feet. By incorporating commercial aesthetic and functional requirements, we hypothesize that we can use this design methodology to create high-performance prosthetic feet that can be customized and provided at scale in the United States. Participants will be asked about their current prosthesis type and use, amputation side and cause, and activity level. We will take measurements of height, weight, and length of the participant's residual limb. The participant will be asked to walk in several prosthetic foot conditions in multiple walking activities, and the visit should last approximately four hours. For each prosthetic foot, a trained prosthetist will fit the foot (either a prototype foot or a commercially available K3/K4 foot) to the prosthesis. The patient will then walk around the room until they feel comfortable. They may initially walk using a gait belt or between parallel bars based on comfort level and an evaluation by the prosthetist. Once they feel comfortable walking on level ground at a normal speed and the prosthetist feels that they will be safe performing more challenging walking activities, the participant will perform different walking activities (such as walking on flat ground at different speeds, walking up/down ramps, and walking up/down stairs). They will then be asked to tell the investigator what you like and dislike about the prosthetic foot. Participants may also be asked to walk while wearing inertial measurement units (IMU's), which are wearable devices similar in size to a pedometer or wrist watch. These devices will record the acceleration of the limbs, which will allow us to understand how people walk in the different prosthetic feet. We will attach the IMU's using their elastic bands, and we will attach necessary wires with hypoallergenic tape. Wearing the IMU's, the participant will walk back and forth in the room while the sensors record information about how you are walking. They may rest at any time.

Official Title
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Evaluation of High-Performance, Customized, Rapidly-Manufacturable Prosthetic Feet That Provide Improved Mobility

Conditions
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Amputation of Lower Limb Below Knee

Intervention / Treatment
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* Drug: Commercially-available energy storage and return prosthetic foot
* Device: MIT-Lower Leg Trajectory Error (LLTE) customized prosthetic feet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Unilateral transtibial amputation Aged between 18-65 years Body mass index between 18.5-29.9 (healthy weight) Daily use of their clinically-prescribed prosthesis for ambulation without an assistive device Classified as at least a Medicare Functional Classification Level K3 (defined as a patient who is a typical unlimited community ambulator) Experience walking with a prosthesis for at least one year Residuum and amputated side in good condition (e.g., no adherent scars, lesions, ulcers, or infections) Normal or corrected vision Ability to walk continuously for 45 minutes without undue fatigue or health risks. Exclusion Criteria: Subjects who weigh more than 200 pounds Poor fitting prosthetic socket Skin problems on the residual limb Co-morbidities or pathologies (other than the amputation) or medications that would affect the sound limb, spine, balance, or stability Decision by prosthetists at Hanger that walking on the prototype limb may pose higher than minimal risk for a potential subject.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Below knee amputees<br>Adult, unilateral trans-tibial amputees (amputation is below the knee and only on one side) who will wear and test our prototype prosthetic feet | Drug: Commercially-available energy storage and return prosthetic foot<br>* Each patient will walk in the Freedom Highlander, a commercially-available energy storage and return prosthetic foot. The foot will be sized based on the patient's foot size and weight.<br>* Other names: Freedom Highlander;Device: MIT-Lower Leg Trajectory Error (LLTE) customized prosthetic feet<br>* Each patient will walk in prosthetic feet designed by the researchers at MIT. These feet will be customized for the user based on their body size (ie, height, foot length) and weight.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of patients who prefer each prosthetic foot tested for each walking activity | For each walking activity, subjects will qualitatively select which foot option they prefer for each activity (ie, standing, walking at varied speeds on level ground, and walking up/down ramps). Subjects will provide this information through a questionnaire where they indicate their preferred foot for each activity. | At the end of study completion, after  4 hours of total time on a single day to acclimate to all prosthetic feet tested | 
| Mean difference in prosthetic foot evaluation score between prototype prosthetic feet and commercial prosthetic feet, as assessed by a self-reported questionnaire | For each prosthetic foot, patients will fill out a questionnaire, which is a modified form of the standardized prosthesis evaluation questionnaire (PEQ). The PEQ is a clinically-validated, self-report questionnaire used to assess the prosthesis and life with the prosthesis. Questions are evaluated on a Likert scale (ie, Strongly disagree to Strongly agree) which will be converted to numerical values. A low score represents a poor rating (the patient did not like the device) and a high score represents a strong rating. The overall outcome measure is the difference in total score (totaled across all questions) between each foot condition. The score for an individual foot represents an overall evaluation of that prosthesis, which we will average across participants and compare between feet. The difference in scores evaluates the feasibility of the prototype foot compared with the subject's own, daily-use prosthesis as well as the commercially available control prosthetic foot. | At the end of study completion, after  4 hours of total time on a single day to acclimate to all prosthetic feet tested | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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transtibial amputation, below knee amputation, prosthetic device design, biomechanics