Clinical Outcomes With Passive MPKs vs. Powered Prosthetic Knees by K4-level Transfemoral Amputees
Phase: NA
Conditions: Amputation, Amputation; Traumatic, Leg, Lower, Limb; Absence, Congenital, Lower, Prosthesis User, Lower Limb Amputation Above Knee (Injury), Amputation; Traumatic, Leg: Thigh, Between Hip and Knee
Sponsor: Liberating Technologies, Inc.

 
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Clinical Outcomes with MPKs vs. Powered Prosthetic Knees by K4-level 
Transfemoral Amputees 
Investigators 
Shane Wurdeman, PhD 
Hanger Institute for Clinical Research and Education 
10910 Domain Drive, Suite 300 
Austin, TX 78758 
(402)-290-8051 
 
Jennifer Johansson, MS 
Liberating Technologies, Inc. 
325 Hopping Brook Road, Suite A 
Holliston, MA 01746 
(774)-233-0874  
 
Funding Source 
Department of Defense  
IRB Protocol # 
20216190 
NCT# 
NCT05267639 
Version 
V2.3 
IRB Approval Date 
August 28, 2022 
 
 
 
 
 
 
 

 
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1. Background and Introduction 
Transfemoral amputation (TFA) results in significant changes in body structures which impact function, including 
bipedal activities essential in community living. Mechanical knees and microprocessor-controlled prosthetic 
knees (MPKs), such as those shown in Figure 1 below, are the current standards of care and can replace some of 
the lost function due to TFA, but not all. This is evidenced by the fact that individuals with TFA have been shown 
to have increased metabolic energy expenditure [1, 2], decreased walking speed [3, 4], increased frequency and 
fear of falls and stumbles [5, 6], decreased balance [7, 8], reduced 
activity levels [9, 10], and increased difficulty navigating slopes 
[11], stairs [12], and uneven terrain [13]. In addition, persons with 
TFA are at much greater risk of developing long-term secondary 
health problems, such as osteoarthritis, osteoporosis, higher rates 
of hip replacement surgeries, residual limb discomfort, low back 
pain, weight gain, and cardiovascular disease [14, 15]. These 
increased risks have been associated with the abnormal 
biomechanical effects of utilizing passive prostheses, which are 
unable to restore the concentric power at the knee and ankle joints 
needed for typical biological gait [16].  
Powered prosthetic knees have the potential to restore lost knee 
power. There is currently one commercially-available powered 
prosthetic knee (Össur’s Power Knee™ (PK), Iceland; Figure 1D) with others under development. Like 
traditional MPKs, powered knees detect the person’s activity, but unlike MPKs, powered knees are able to provide 
power at the appropriate time to assist the user in a number of ambulatory tasks. For example, powered knees can 
actively lift the foot during swing flexion to increase ground clearance independent of the walking speed or type 
of activity. Possibly most advantageous, powered knee extension assists when standing up from a chair and 
walking up slopes, as well as allowing for step-over-step stair ascent. These advantages intend to reduce the 
burden to the non-amputated contralateral limb.  
Studies have been conducted to validate the claims that active knee flexion and extension assist the user to achieve 
more symmetric and biomimetic mechanics, with the goal of ultimately reducing overuse injuries and wear and 
tear on the intact limb. These studies examined level walking [16, 17, 18], sit-to-stand and stand-to-sit activities 
[19-22], walking up and down slopes [23], and walking up and down stairs [23]. Benefits were shown in areas 
such as energy expenditure during level walking [16] and ramp ascent [23], improved biomechanics and 
symmetry during sit-to-stand [20, 21], stairs and ramps [23], and level walking [17, 18], as well as perceived 
exertion during long-distance ambulation [18]. However much of this work was performed in a laboratory setting 
making translation of these findings to community use unclear. Similarly, the limited testing that has been 
performed in a community environment has been on Medicare Functional Classification Level 3 (i.e., K3) 
individuals [24] who entered the study as non-MPK users, with only three patients completing the full protocol. 
There is a lack of testing outside the laboratory on active individuals with TFA and therefore, community testing 
of individuals with TFA classified as K2, K3 or K4 ambulators is needed to guide clinical decision making and 
improve clinical outcomes. 
 
 
 
Figure 1 | Examples of commercially-available 
prosthetic knees: (A) Otto Bock C-leg, (B) Össur 
Mauch®, (C) Össur Rheo®, (D) Össur Power 
Knee™.   

 
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2. Study Rationale 
This study will focus on investigating the tradeoffs between powered knees and traditional MPKs to identify the 
prosthetic knee that is best suited for users during different tasks. We will assess measured, observed, and self-
reported outcomes achieved through real-world use of these prosthetic knees. 
 
The results of this study will (1) provide initial evidence to guide clinical prescription and use of powered knee 
technologies for K2, K3 or K4-level individuals with sound scientific data, (2) provide pilot data for a larger 
clinical trial to further inform the evidence-based prescription of powered knee technologies across multiple K-
levels, and (3) obtain data that can be disseminated to other researchers and inform the design of future powered 
prosthetic knees by understanding the needs of users and identifying the features and functions that are most 
valuable to these patient populations, as well as evaluating the capabilities and limitations of current devices.  
 
3. Outcomes 
To achieve our goals, we will explore the following specific aims: 
Specific Aim 1: To evaluate the longitudinal mobility of individuals with TFA with each prosthetic knee 
by monitoring activity parameters and assessing performance on functional measures and activities 
representative of community participation.  
Specific Aim 2: To evaluate the longitudinal safety of individuals with TFA with the use of each prosthetic 
knee by monitoring measures of balance confidence, exertion, and fatigue, as well as the number of falls.  
Specific Aim 3: To evaluate the longitudinal well-being of individuals with TFA with the use of each 
prosthetic knee by soliciting feedback on self-reported measures of health-related quality of life.  
Figure 2 | Study outcome measures 

 
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To address our specific aims, we will administer a suite of physical and self-report measures to assess functional 
and perceived differences between the knee conditions, similar to what was performed by Hafner, et. al. [24] 
(Figure 2). We recognize that we have a large number of assessments; however, as a pilot study, we will seek to 
capture as much information as possible from a small number of individuals to ensure that the follow-on, larger 
full-scale clinical trial will focus on the most relevant measures.  
 
4. Study Design 
We plan to perform a pilot longitudinal randomized crossover study to compare the effects of power at the knee 
in individuals with unilateral transfemoral amputation (Figure 3). The two interventions, or conditions, to be 
tested are: (A) a powered prosthetic knee and (B) an MPK. For this study we will recruit individuals who are 
currently MPK users; therefore, for the MPK condition, they will wear their usual prosthesis (e.g. Otto Bock C-
leg, Össur Rheo, etc) as they represent the current standard of care. This will be recorded as a potential confounder 
in post-hoc analysis. For the powered knee condition, each subject will be provided with the Össur Power Knee, 
which is the only powered knee that is commercially available at this time.  
The order these conditions are tested in will be randomized across subjects. Block randomization using a 
previously developed custom software based on random number generation will be used to equally distribute the 
subjects into the 2 possible intervention orders (AB or BA). For each condition, the subject will be trained on and 
acclimated to the device during the first month of the take-home period, and then will continue to wear it at home 
after training for a total of three months per condition. There may be seasonal effects due to the timing of when 
the various test conditions are administered, however, we plan to offset these effects with condition 
randomization, multiple site testing, and staggered start times. 
 
Testing will consist of test sessions, training sessions, at-home wear of the device, and functional and self-report 
assessment at the end of each intervention condition (Figure 3). If the subject’s current foot is not compatible 
with the Power Knee, they will be provided with a commercially available prosthetic foot for the study. In this 
case, the subject will be given an initial acclimation period of 1 month on the new foot before starting 
interventional testing.  
 
Figure 3 | Study Design - Longitudinal Randomized Crossover Study 

 
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After receiving IRB and HRPO (US Army Human Research Protection Office) approval, subjects will be recruited 
and screened for eligibility. If they are eligible and decide to participate, they will be scheduled for their first site 
visit. They will either be consented over the phone before their first site visit or at the first site visit (‘1’ in Figure 
3). If over the phone, study staff will use the telephone script to confirm eligibility and guide the subject through 
consent form details. Subjects will be provided the informed consent form to read through entirely before signing, 
and are encouraged to ask questions at any time.  
Prior to each condition, each subject will be fit and aligned on the knee by a trained certified prosthetist. An 
activity monitor (such as the GeneActiv™) will be worn by the subject. As we have done in prior studies, we will 
use the activity monitor to track the number of steps the subjects take in each condition. Each subject will wear 
the same foot for all study periods for comparability between the two knee conditions. 
The subject will wear the knee being tested at home for three months. During the first month of each condition, 
subjects will be given time to acclimate to the knee being tested. Subjects will participate in at least two, but up 
to eight, 1 hour training sessions. At a minimum, each subject will receive one training session to learn how to 
properly use each device for a variety of daily activities and a second session to demonstrate retention of the 
learned skills. The subject will continue training until they show retention of the understanding and/or proficiency 
of the device functions or until they have received eight training sessions, whichever comes first. After 8 training 
sessions, they will have completed all of the available training and will therefore continue with the study at their 
current proficiency level. For the powered knee condition, we will work with trained and experienced clinicians, 
consulting prosthetic knee manufacturers as needed, to develop the training protocol and determine proficiency.  
Subjects will be asked to continue to wear the knee full time for the remainder of the three month take-home 
period. Through Hanger’s current patient care system, we will have the ability to push out a digital to the patient’s 
phone asking them whether they have experienced a recent fall. If they respond positively that they had a fall, 
follow up questions can be asked to get more specific details about the fall. After three months of at-home wear, 
the subject will return for the second test visit. During that visit, functional tests and self-report surveys will be 
administered. At the completion of the second test visit (Period 1), the subject will then be fit and aligned on the 
prosthetic knee condition for Period 2. The training, at home wear, and in-clinic assessments will be repeated for 
the next knee condition. The overall study plan and schedule is summarized in Table 1 below. 
 
 

 
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Table 1 | Subject study schedule 
 
Sequence 
Duration 
Description 
⓪ 
Period #0 
1 month 
If the subject’s current foot is not compatible with the Power Knee, they will 
be provided a foot for the study. They will be given an acclimation period 
of 1 month on the provided study foot. 
◆ Test Session #1 
2 hours 
The subject will be fit with a prosthetic knee configuration and an activity 
logger. They will conduct standardized functional tests and assessments. 
① 
| 
Period #1 
3 months 
First three-month period of the study. Three months of using the prosthetic 
knee at home. 
◇ 
Training 
Sessions 
1 hour /each 
One-hour sessions will be scheduled during the first month of the take-home 
period for training on walking with a prosthetic knee configuration. Two to 
eight sessions will be required. At the first and last training sessions, 
standardized functional tests and assessments will be conducted. 
◆ Test Session #2 
4 hours 
The subject will conduct standardized functional tests and assessments on 
the first knee configuration. They will then be fit with their second prosthetic 
knee configuration and an activity logger.  
② 
| 
Period #2 
3 months 
Second three-month period of the study. Three months of using the 
prosthetic knee at home. 
◇ 
Training 
Sessions 
1 hour /each 
One-hour sessions will be scheduled during the first month of the take-home 
period for training on walking with a prosthetic knee configuration. Two to 
eight sessions will be required. At the the first and last training sessions, 
standardized functional tests and assessments will be conducted. 
◆ Test Session #3 
2 hours 
The subject will conduct standardized functional tests and assessment. This 
is the final study event. Any study device or equipment will be returned, and 
their prosthesis reconfigured to its original state. 
 
5. Study Population 
The proposed work will include recruiting persons with transfemoral amputation for take-home testing of two 
prosthetic knees in a randomized crossover design. A statistical power analysis revealed that 12 subjects would 
be required to achieve the desired statistical power to determine whether individuals are more active when wearing 
a powered knee than a traditional MPK prosthesis as measured by the daily number of steps taken. This power 
analysis aligns with the recommendation of Moore, et al. [35] to include 12 subjects to estimate average values 
and variances of our specific outcome variables in our target population. We recognize that this pilot study may 
not demonstrate definitive evidence for a treatment effect of the intervention. However, it provides the means to 
gather the data and experience necessary to optimize value and practicality for a subsequent clinical trial. 
Therefore, based on the above, this study will require data from 12 individuals with transfemoral limb absence 
who use an MPK. However, we will target recruitment of 15 individuals for participation, to allow for up to 20% 
dropout.  
While the recruitment of anything above a modest number of people with a limb absence can be challenging, the 
multiple locations of Hanger Clinics will help mitigate this risk and increase our pool of potential subjects from 
multiple geographic areas. Dr. Shane Wurdeman has been able to preemptively identify the locations within 
Hanger’s network of approximately 800 prosthetic clinics nationwide to focus recruitment at those sites with a 

 
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large population of transfemoral, K4, K3 and K2 prosthesis users. If recruitment challenges are encountered, he 
will onboard additional clinical sites as needed to mitigate recruitment issues.  
 
6. Participant Eligibility 
Up to 15 people will be recruited for testing. Individuals who meet the following inclusion criteria will be included 
in the study:  
▪ Are at least 18 years old 
▪ Unilateral transfemoral prosthesis user (limb absence between the knee and hip) 
▪ Current user of a microprocessor-controlled knee (MPK) 
▪ Have adequate clearance between distal end and ground for necessary knee and foot components 
▪ Medicare Functional Classification Level (K-Level): 2, 3, or 4 
▪ Socket-Comfort Score: 6 or above to ensure adequate socket fit 
▪ Six months or more experience on a prosthesis 
▪ Body weight between 50kg and 116kg (110lbs - 256lbs)  
Exclusion criteria are:   
▪ Present injuries to residual limb or contralateral leg affecting functional ability 
▪ Socket issues/changes in the last 6 weeks 
▪ Users with bone-anchored implants 
Subjects can be excluded at the discretion of the investigator for other unforeseen disqualifying criteria (such as 
specific cognitive issues, etc.). Subjects in this study will not be discriminated by sex/gender or race/ethnicity.  
Using a knee that the subject is unfamiliar with may increase the risk of falling. Therefore, pregnant women 
should not participate in the study and will be screened by self-disclosure. 
 
7. Study Methodology 
Timeline: Subject participation in this study will span six months with two, 3-month at-home study periods. 
Subjects will be asked to attend 2 to 8 training visits, conduct normal activity at home, document their falls, and 
complete a series of functional tests and self-report surveys upon their return to the clinic. Site visits will take 
approximately 2 to 4 hours. Additional site visits may be scheduled if issues arise (issues with alignment, time 
constraints, etc.). 
If the subject’s current foot is not compatible with the Power Knee, they will be provided a standard foot for the 
study and given an initial acclimation period of 1 month before site visit 1. In this case, subjects will be consented 
before (over the phone) or during their initial visit in which the prosthetist will align them on the foot provided 
for this study. Subjects are free to terminate a session and their participation in this study whenever they wish. 
The specific study events are detailed below. 
 
Site Visit <1> 

 
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If the subject has not yet been consented, they will begin the process of informed consent where all of the details 
of the research study will be explained at this start of this visit. Subjects are allowed to take the consent form 
home with them and show it to friends, family, and their physician in order to make an informed decision to 
participate in the study. Once consented, demographic information, including height, weight, and type of 
prosthetic foot and socket suspension, will be collected from the subject. 
The subject will then be fit and aligned with the first prosthetic knee by a certified prosthetist. An activity monitor  
will be worn by the subject to monitor daily step count.  
This visit will take up to 2 hours. 
 
Period 1: At-Home Participation Months 1-3 
During the first month of the take-home period, subjects will be trained on the knee they are wearing and allowed 
time to acclimate to it at home. At a minimum, each subject will receive one training session to learn how to 
properly use each device for a variety of daily activities and a second training session to demonstrate retention of 
the learned skills. At the beginning of the first training session, standardized functional tests and assessments will 
be conducted. 
Subjects will be asked to complete a series of functional tests and self-report surveys to assess their mobility, 
safety, and well-being. The measures that we may use are: 
Specific Aim 1- Mobility 
For aim 1, we plan to administer outcome measures such as: step count, the Six Minute Walk Test (6MWT) [25], 
Stair Assessment Index (SAI) [26]; Ramp Assessment Index (RAI) [26]; TUG [27]; Patient Reported Outcomes 
Measures Information System (PROMIS) Physical Function (-PF) short form [24]; and the Prosthetic Limb Users 
Survey of Mobility (PLUS-M) [28].  
Specific Aim 2 - Safety 
For aim 2, we plan to administer outcome measures such as: the Activities-Specific Balance Confidence (ABC) 
scale [29], the Borg Rating of Perceived Exertion Scale (RPE) [30], heart rate (to calculate the Physiological Cost 
Index (PCI) [36], the PROMIS- Fatigue (PROMIS-FAT) short form [29], and number and details of self-reported 
falls. 
Specific Aim 3 – Wellbeing 
For aim 3, we plan to administer outcome measures such as: PROMIS-29 short form [31], the Oswestry Disability 
Index (ODI) [32], Prosthesis Evaluation Questionnaire-Well Being (PEQ-Well Being) [33], and the PROMIS-
Ability to Participate in Social Roles and Activities (PROMIS-APSRA) short form [34]. 
After completing these measures, the subject will complete their initial training session for the first knee condition.  
 
The subject will continue training until they show retention of the understanding and/or proficiency of the knee 
functions or until they have received eight training sessions, whichever comes first. At the end of the last training 
session, standardized functional tests and assessments will be conducted (such as those described in training 
session 1). Then during the following two months, the subject will be asked to continue using the knee full-time.  

 
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Study staff may call or email the subject periodically to check-in and answer any questions they may have. A 
digital fall questionnaire will be delivered at most weekly through a HIPAA secure system to the patient’s phone. 
If they respond positively that they had a fall, follow up questions can be asked to get more specific details. The 
subject may be asked to provide additional notes periodically to document their problems, experiences, and 
feedback.  
This portion of the study will be three months long.  
 
Site Visit <2> 
After three months of at-home wear, the subject will return for the second test visit. Subjects will be asked to 
complete a series of functional tests and self-report surveys on the first knee configuration. 
Once the subjects have completed the functional tests and assessments, the activity monitor will be removed, and 
the knees will be swapped. The subject will be fit and aligned with the second prosthetic knee by a certified 
prosthetist. The activity monitor will then be placed back on the subject for condition 2. 
This visit will take approximately 4 hours. 
 
Period 2: At-Home Participation Months 4-6 
This period is the same as Period 1, except subjects will be testing and training on the second prosthetic knee.  
This portion of the study will be three months long.  
 
Site Visit <3> 
At the end of Period 2, subjects will return to the clinic. They will be asked to complete a series of functional tests 
and self-report surveys on the second knee configuration. After completing these measures, the activity monitor 
will be removed, and the subject will be set back up on their usual prosthetic knee and foot by a certified 
prosthetist. At this time, the subject has completed the study. 
This visit will take approximately 2 hours. 
 
8. Study Conduct 
Subjects will be screened and consented for eligibility criteria. If they decide to participate, they will be set up 
with the first prosthetic knee being tested. The study will consist of two, three month periods where subjects will 
be trained on the knees, use the prosthetic knees at homes and document any falls and feedback on the knees. At 
the beginning and end of each knee condition, as well as at their final training session, subjects will complete a 
series of functional tests and self-report surveys. 
Subjects may withdraw at any time by simply telling the investigators they wish to stop their participation. 
If a subject withdraws from the study, the data that were collected from them can still be used, and the withdrawn 
subjects may be replaced with a new subject. Deviations from the protocol that increase risks for subjects will be 
reported to WCG and HRPO for approval prior to being implemented. 

 
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Subjects will be compensated for the Site Visit milestones described in Section 7: Study Methodology. They 
will receive $50 for Site Visit 1, $100 for Site Visit 2, and $150 for Site Visit 3, for a total of $300 for completing 
all visits. Subjects will also receive $50 for completing 2 months, $100 for completing 4 months, and $125 for 
completing 6 months of the study, for a total of $275 for finishing the take-home portion of the study. Upon 
completion of the study and return of study materials, subjects will receive an additional $200. The total 
anticipated payment for this study is $775 per subject. 
 
9. Study Treatment 
The Ӧssur Power Knee is currently the only commercially-available powered prosthetic knee. The intervention 
being tested in this study is the newest version of this product, Ӧssur Power Knee III™ (Figure 4). 
The Power Knee III contains design improvements to optimize features such as the control strategy, weight, and 
battery life. According to the Power Knee’s instructions for use, the device is comprised of a proximal pyramid 
adapter, motor, power button and status indicator, battery, charging port, battery indicator, battery button, and 
distal pyramid connector.  
A second intervention, the subject’s usual MPK, will also be tested as a baseline measure. All MPKs used for this 
condition (i.e., Otto Bock C-leg, Össur Rheo, Freedom Innovations Plié, and Blatchford Orion) are commercially 
available. This configuration will be the same knee system the subject usually uses and will be tested for the 
purpose of comparing outcomes between their existing knee and the provided powered knee device. 
Subjects will be instructed upon the device design and features and allowed time to practice operating the device 
using conventional strategies for powered knee prostheses. Fittings and trainings will be conducted with a certified 
prosthetist and/or physical therapist.  
 
Figure 4 | Rendering of the Ӧssur Power Knee III  

 
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10. Evaluation of Adverse Events 
The main risk of the devices, inherent to all lower limb prostheses, is injury from tripping, falling, or losing 
balance. Changing from the user’s usual MPK to the Power Knee and back may increase the risk of falls. The 
user may also experience fatigue during in-clinic testing. To mitigate the risk of tripping, falling, or losing balance, 
a certified prosthetist will fit the subject with all prosthetic components. Users will be provided with instructions, 
training, and acclimation periods for each knee configuration. Safety methods (such as handrails, parallel bars, 
spotters, gait belts, overhead harnessing, etc.) will be available during in-clinic testing to mitigate fall or trip 
hazards. Training will be conducted in a clinic setting before subjects are sent home with any new devices. If the 
user feels as though the prosthetic knee is giving them trouble at home, they may schedule a visit with their 
prosthetist to fix any issues, or configure them back on their usual knee if the problem persists. To mitigate any 
fatigue during in-clinic training and testing, rests and break periods will be allowed and encouraged at the 
subject’s discretion to ensure they are comfortable while training and performing tests with the study knees. 
All unanticipated problems involving risk to subjects or others, serious adverse events related to participation in 
the study and subject deaths related to participation in the study will be promptly reported to the WCG IRB and 
HRPO. A written description of the adverse event will be stored in the study file maintained by the Principal 
Investigator (PI). Also, the protocol will be reviewed in light of the adverse event to determine if modifications 
need to be made to prevent the event from occurring again. Major modifications to the research protocol and any 
modifications that could potentially increase risk to human subjects must be submitted to the WCG IRB and 
HRPO for approval prior to implementation. 
 
11. Ethical Considerations 
Individuals receiving the powered knee will get to experience an extended at-home trial period. Beyond this, the 
powered prosthetic knee device provides no further known direct benefit to the subjects. Their participation in 
this study will expand the knowledge of the prosthetic community by further understanding how users benefit 
from each of the prosthetic knees being tested. This research will in turn help physicians and prosthetists make 
more informed decisions when determining which devices are best for their patients. 
The protocol, consent form, and recruitment flyer will require IRB review and approval. The principal 
investigators will be in continuous communication with WCG IRB HRPO. Subjects’ participation is voluntary, 
and they may withdraw from participation in the study at any time by simply saying that they wish to stop. The 
investigators may choose to terminate a subject’s participation if he or she experiences discomfort or injury. In 
addition, subjects will be given any new information which is discovered during the course of the study which 
may influence subjects’ willingness to continue the study. If they desire to do so, subjects’ will also have the 
option to discuss any concerns regarding the study activities or the investigators with an impartial staff member 
of the IRB, whose duty it is to hear and review such concerns and provide advice or take any other appropriate 
actions. 
The investigators will ensure the anonymity of all subjects in this study. After completing the consenting process, 
subjects will be assigned a unique alpha-numeric identification number. The number will be used on all test data 
associated with the subject. No personal identifiers will be associated with the data collected from the subjects 
during the study. The PI will have a master document linking the subject name with ID number, and it will be 
stored on a password protected computer, with only the PI and approved study staff having access to the master 

 
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list. Only the de-identified data will be shared with Liberating Technologies, Inc. using subject and condition 
number for data analysis. Data will be stored in a secure manner depending on the media: either a password 
protected computer with access limited to the co-investigators, or in a locked filing cabinet in the investigator’s 
office. A copy of the test data will also be retained by the PI in the program folder, also stored in a secured manner. 
As with anything, there is the potential of a data breach, however the described steps taken to keep subject 
information secure will minimize this risk. 
 
12. Study Monitoring and Oversight 
Liberating Technologies, Inc., as the clinical trial sponsor, plans to meet all requirements outlined in US federal 
regulations and International Council for Harmonisation (ICH) E6 for monitoring to ensure that site investigators 
comply with the protocol, all regulations, and Good Clinical Practice (GCP). The PI will ensure the rights and 
well-being of human subjects are protected, all data reported is accurate and complete, and that the conduct of the 
trial is in compliance with the approved protocol, GCP, and other regulations. 
De-identified data, photos, and videos will be kept indefinitely to show in scientific presentations and 
publications. Photos will not contain any identifying information about the subject. Photos will not include the 
subject’s face or any identifying marks such as tattoos. If identifying photos happen to be received from a subject, 
they will be de-identified by either cropping or blurring using photo-editing software. 
Additionally, representatives of the United States Army Medical Research Acquisition Activity (USAMRAA) 
are eligible to review research records as a function of their responsibility to protect subjects in research. 
 
13. Investigational Product Management 
All devices being tested are commercially available prosthetic knees.  
 
14. Data Analysis 
The data collected in the in-clinic and take-home portions of this study will include number of steps and number 
of self-reported falls, and a series of standard outcomes measures, including:  6MWT, SAI, RAI, TUG, PROMIS-
PF short form, PLUS-M, ABC, RPE, PROMIS-Fat, PROMIS-29, ODI, PEQ-Well Being, and PROMIS-APSRA 
short form.  
The primary statistical analysis will be led by Dr. Newton and will employ a linear mixed model. It will not 
include carryover effects as the training and acclimation period in the first month of each condition will constitute 
the washout period for the prior knee. Additional predictors will include a fixed effect for gender and MPK as 
well as a random effect for test clinic to account for potential differences between sites.  
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