Transfemoral AmputationMPK-K2NCT07103798
Effect of a Microprocessor-controlled Prosthetic Knee Joint on K2 Level Ambulators
A study testing College Park ICON and Conventional NMPK in people with Transfemoral Amputation and Limb Loss, run by VA Office of Research and Development at 2 sites in United States.
Trial summary
Microprocessor-controlled knees (MPKs) automatically adjust resistance or damping in the joint to improve swing- and/or stance-phase control as appropriate for the prosthesis user during gait. Read more about this study
- Who is it for?
- Ages 45 to 85 years
- Conditions the study is for
- Transfemoral Amputation, Limb Loss, Limb Absence
- What is being tested?
- College Park ICON and Conventional NMPK
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 2 sitesUnited States
- Study dates
- 4 Jan 2027to 30 Sep 2028
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 45 to 85 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Unilateral, transfemoral amputation (any etiology)
- Residual limb length classified as standard (i.e., medium) to long
- Prosthesis user for at least 1 year prior to enrolling in the study
- K2-level classification while using their nonmicroprocessor-controlled knee (NMPK)
- Good sensation on their residual limb
- Good skin integrity upon visual inspection
- Presents with good socket fit based upon a standard assessment by the study prosthetist
Who cannot join
- Bilateral leg amputations
- Individuals with a knee disarticulation
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
United States2 sites
Jesse Brown VA Medical Center, Chicago, IL
Chicago, Illinois, 60612
Rebecca Stine, MS, (312) 503-5726, rebecca.stine@va.gov
Steven A Gard, PhD, (312) 503-5718, steven.gard@va.gov
Edward Hines Jr. VA Hospital, Hines, IL
Hines, Illinois, 60141-3030
Rebecca Stine, MS, 312-503-5726, rebecca.stine@va.gov
Steven A Gard, PhD, 3125035718, steven.gard@va.gov
About this study
Official title: Does a Microprocessor-Controlled Prosthetic Knee Joint Improve Mobility and Quality of Life in K2-Level Veteran Ambulators?
Microprocessor-controlled knees (MPKs) automatically adjust resistance or damping in the joint to improve swing- and/or stance-phase control as appropriate for the prosthesis user during gait. The purpose of this proposed investigation is to determine if there are substantial physical and psychological benefits to fitting lower functioning Veteran ambulators having transfemoral amputations with an MPK compared with a nonmicroprocessor-controlled knee (NMPK). Using a repeated-measures, cross-sectional experimental design, approximately 20 Veterans with unilateral, transfemoral amputations will be evaluated on two separate occasions at the Jesse Brown VA Medical Center or the Edward Hines, Jr. VA Hospital, first with their conventional NMPK and then again after a 2-month accommodation period with the College Park Icon MPK.
Read the detailed description
Limb loss is a potentially devastating event in a person's life, often resulting in profound physical, psychological, and vocational consequences. A transfemoral amputation results in greater physical and functional impairment and an increased risk of falling in patients as compared to someone with a transtibial amputation. Furthermore, balance confidence and fear of falling appears to be a persistent and pervasive problem among lower-limb prosthesis users, which adversely affects mobility and quality of life. During the past 30 years there have been several major developments in prosthetic knee mechanisms that incorporate microprocessors to improve swing-phase characteristics and provide greater stability during stance phase. Microprocessor-controlled knees (MPKs) automatically adjust resistance or damping in the joint to improve swing- and/or stance-phase control as appropriate for the user during gait.
There are numerous reported benefits of MPKs over non-microprocessor controlled knees (NMPKs), including faster self-selected walking speeds, reduced cognitive burden while walking, fewer stumbles and falls, and increased perceptions of confidence and safety while ambulating. Nonetheless, MPKs are not typically prescribed or fitted on lower functioning ambulators, which is the activity classification of most Veteran patients.
The purpose of this proposed investigation is to determine if there are substantial physical and psychological benefits to fitting lower functioning Veteran ambulators having transfemoral amputations with an MPK compared with a NMPK. The specific aims and hypotheses of this project are:
Aim 1: To determine the effects of the College Park Icon on the mobility of unilateral, transfemoral prosthesis users. The investigators hypothesize that the MPK will enable users to 1) increase their freely-selected (i.e., normal) walking speed, and 2) walk over a wider range of speeds. Furthermore, the investigators hypothesize that 3) participants will report fewer falls with the MPK.
Aim 2: To determine the effects of the College Park Icon on the psychological well-being of unilateral, transfemoral prosthesis users. The investigators hypothesize that subjects will improve their scores on patient-reported outcome assessments including the ABC, OPUS, and PLUS-M with the MPK.
Aim 3: To determine subjects' preference for the College Park Icon compared to their conventional NMPK. At the completion of the study, the investigators will ask participants which prosthetic knee type they preferred. It's hypothesized that the majority of participants will prefer using the MPK over the NMPK. Those subjects who prefer the MPK will be permitted to keep the component in their prosthesis, while those who prefer their NMPK will have their prosthesis returned to its original configuration.
Using a cross-sectional experimental design, approximately 20 Veterans who are low functioning ambulators with unilateral, transfemoral amputations will be evaluated on two separate occasions at the Jesse Brown VA Medical Center or the Edward Hines, Jr. VA Hospital, first with their conventional NMPK and then again after a two-month accommodation period with the College Park Icon MPK.
This work is directly applicable to VHA's Patient Care Mission because the results may justify the fitting of MPKs on low-level ambulators within the VA system and substantially improve the mobility of Veterans with lower limb amputations while increasing their quality of life.
- Conditions
- Transfemoral Amputation, Limb Loss, Limb Absence
- Being tested
- College Park ICON, Conventional NMPK
- Keywords
- amputation, limb loss, limb deficiency, transfemoral, above-knee, prosthesis, knee joint
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
College Park ICONOther
Subjects will be fitted and trained on the College Park ICON MPK. An accommodation period of 2 months will be provided prior to evaluation with the knee joint.
Conventional NMPKOther
Subjects will be tested walking with their conventional, mechanical prosthetic knee prior to being fitted with the MPK.
| Study group | Role | What they receive |
|---|---|---|
| Microprocessor-controlled knees (MPK) | Experimental | Subjects will be fitted with the College Park ICON MPK and permitted to accommodate for 2 months prior to data collection. Receives: Other: College Park ICON |
| Nonmicroprocessor-controlled knee (NMPK) | Active comparator | Subjects will initially be evaluated walking on their conventional NMPK as a baseline prior to being fitted with the MPK. Receives: Other: Conventional NMPK |
What is being measured
The primary outcome is the main question the study is designed to answer.
Walking speed
Walking speed will be measured as participants walk on level ground at slow, normal and fast speeds.
Measured: To be measured before and immediately following the 2-month accommodation period of wearing the microprocessor-controlled knee the microprocessor-controlled knee (MPK)
Falls during walking
The number of falls that occur while the subject is walking will be recorded in a daily diary.
Measured: To be determined before and during the 2-month accommodation period of wearing the the microprocessor-controlled knee (MPK)
PLUS-M
The Prosthetic Limb User Survey of Mobility (PLUS-M) will be used to determine the mobility of subjects before and after fitting with the MPK. Scores range from 12-60 points, and a higher score indicates greater mobility.
Measured: To be measured before and immediately following the 2-month accommodation period of wearing the the microprocessor-controlled knee (MPK)
Prosthetic Knee Preference
Subjects will be asked which prosthetic knee they prefer at the completion of the study. For those that indicate preference for the the microprocessor-controlled knee (MPK), they will be permitted to keep it in their prosthesis. For those that prefer the nonmicroprocessor-controlled knee (NMPK), their prosthesis will be restored to the configuration prior to beginning the study.
Measured: To be asked immediately following the 2-month accommodation period of wearing the the microprocessor-controlled knee (MPK)
Secondary outcomes (2)
ABC Scale
The Activities-specific Balance Confidence (ABC) Scale measures the subject's confidence in not losing their balance or becoming unsteady while performing different activities. Scores range from 0-100%, where zero represents no confidence and 100 represents complete confidence in performing an activity without losing balance or becoming unsteady.
Measured: To be administered before and immediately following the 2-month accommodation period of wearing the the microprocessor-controlled knee (MPK)
OPUS
The Orthotics and Prosthetics User's Survey (OPUS) is a self-report questionnaire that can be used for quality assessment, to maintain awareness of improvement in activities, to evaluate changes in patient's functional status and quality of life, and to assess satisfaction with devices and services. Scores range from 0-80 points, with a higher score indicating greater functional mobility.
Measured: To be administered before and immediately following the 2-month accommodation period of wearing the the microprocessor-controlled knee (MPK)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 Aug 2025
- Study start4 Jan 2027 (estimated)
- Primary completion1 Aug 2028 (estimated)
- Study completion30 Sep 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Transfemoral AmputationStudies of the same condition, open and under way.
- More trials run by VA Office of Research and DevelopmentThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Crossover
- Model description
- Using a cross-sectional experimental design, approximately 20 Veterans who are low functioning ambulators with unilateral, transfemoral amputations will be evaluated on two separate occasions at the Jesse Brown VA Medical Center or the Edward Hines, Jr. VA Hospital, first with their conventional NMPK and then again after a two-month accommodation period with the College Park Icon MPK.
- Masking
- None (open label)
- Enrolment
- 20 participants (estimated)
Sponsor and investigators
- Lead sponsor
- VA Office of Research and Development
- Sponsor type
- US federal agency
- Responsible party
- Sponsor
- Investigators
- Steven A Gard, PhD, Principal investigator, Jesse Brown VA Medical Center, Chicago, IL
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07103798
- Sponsor's protocol ID
- RRD2-005-24W
- Other IDs
- RX005610
- Acronym
- MPK-K2
- Status last verified
- Oct 2026
- First submitted
- 15 Jul 2025
- Last updated
- 7 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: A Limited Dataset (LDS) will be created and shared pursuant to a Data Use Agreement (DUA) appropriately limiting use of the dataset and prohibiting the recipient from identifying or re-identifying (or taking steps to identify or re-identify) any individual whose data are included in the dataset. Results from this study will be freely disseminated via presentations at professional conferences and publications in scientific journals. Additionally, data acquired for this project will be shared with those investigators who make a formal request to the PI and can demonstrate a legitimate and justifiable cause for utilization of such data. All requests for these data will be discussed with the VA scientific program manager.
Study at a glance
From the registry record, last updated by the sponsor on 7 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Does a Microprocessor-Controlled Prosthetic Knee Joint Improve Mobility and Quality of Life in K2-Level Veteran Ambulators?
- ClinicalTrials.gov ID
- NCT07103798
- Acronym / sponsor ID
- MPK-K2 / RRD2-005-24W
- Conditions
- Transfemoral Amputation, Limb Loss, Limb Absence
- Keywords
- amputation, limb loss, limb deficiency, transfemoral, above-knee, prosthesis, knee joint
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 20 participants (estimated)
- Lead sponsor
- VA Office of Research and DevelopmentUS federal agency
- Study start
- 4 Jan 2027 (estimated)
- Primary completion
- 1 Aug 2028 (estimated)
- Study completion
- 30 Sep 2028 (estimated)
- First posted
- 5 Aug 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Microprocessor-controlled knees (MPKs) automatically adjust resistance or damping in the joint to improve swing- and/or stance-phase control as appropriate for the prosthesis user during gait. The purpose of this proposed investigation is to determine if there are substantial physical and psychological benefits to fitting lower functioning Veteran ambulators having transfemoral amputations with an MPK compared with a nonmicroprocessor-controlled knee (NMPK). Using a repeated-measures, cross-sectional experimental design, approximately 20 Veterans with unilateral, transfemoral amputations will be evaluated on two separate occasions at the Jesse Brown VA Medical Center or the Edward Hines, Jr. VA Hospital, first with their conventional NMPK and then again after a 2-month accommodation period with the College Park Icon MPK.
Detailed description
Limb loss is a potentially devastating event in a person's life, often resulting in profound physical, psychological, and vocational consequences. A transfemoral amputation results in greater physical and functional impairment and an increased risk of falling in patients as compared to someone with a transtibial amputation. Furthermore, balance confidence and fear of falling appears to be a persistent and pervasive problem among lower-limb prosthesis users, which adversely affects mobility and quality of life. During the past 30 years there have been several major developments in prosthetic knee mechanisms that incorporate microprocessors to improve swing-phase characteristics and provide greater stability during stance phase. Microprocessor-controlled knees (MPKs) automatically adjust resistance or damping in the joint to improve swing- and/or stance-phase control as appropriate for the user during gait.
There are numerous reported benefits of MPKs over non-microprocessor controlled knees (NMPKs), including faster self-selected walking speeds, reduced cognitive burden while walking, fewer stumbles and falls, and increased perceptions of confidence and safety while ambulating. Nonetheless, MPKs are not typically prescribed or fitted on lower functioning ambulators, which is the activity classification of most Veteran patients.
The purpose of this proposed investigation is to determine if there are substantial physical and psychological benefits to fitting lower functioning Veteran ambulators having transfemoral amputations with an MPK compared with a NMPK. The specific aims and hypotheses of this project are:
Aim 1: To determine the effects of the College Park Icon on the mobility of unilateral, transfemoral prosthesis users. The investigators hypothesize that the MPK will enable users to 1) increase their freely-selected (i.e., normal) walking speed, and 2) walk over a wider range of speeds. Furthermore, the investigators hypothesize that 3) participants will report fewer falls with the MPK.
Aim 2: To determine the effects of the College Park Icon on the psychological well-being of unilateral, transfemoral prosthesis users. The investigators hypothesize that subjects will improve their scores on patient-reported outcome assessments including the ABC, OPUS, and PLUS-M with the MPK.
Aim 3: To determine subjects' preference for the College Park Icon compared to their conventional NMPK. At the completion of the study, the investigators will ask participants which prosthetic knee type they preferred. It's hypothesized that the majority of participants will prefer using the MPK over the NMPK. Those subjects who prefer the MPK will be permitted to keep the component in their prosthesis, while those who prefer their NMPK will have their prosthesis returned to its original configuration.
Using a cross-sectional experimental design, approximately 20 Veterans who are low functioning ambulators with unilateral, transfemoral amputations will be evaluated on two separate occasions at the Jesse Brown VA Medical Center or the Edward Hines, Jr. VA Hospital, first with their conventional NMPK and then again after a two-month accommodation period with the College Park Icon MPK.
This work is directly applicable to VHA's Patient Care Mission because the results may justify the fitting of MPKs on low-level ambulators within the VA system and substantially improve the mobility of Veterans with lower limb amputations while increasing their quality of life.
Study design
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Using a cross-sectional experimental design, approximately 20 Veterans who are low functioning ambulators with unilateral, transfemoral amputations will be evaluated on two separate occasions at the Jesse Brown VA Medical Center or the Edward Hines, Jr. VA Hospital, first with their conventional NMPK and then again after a two-month accommodation period with the College Park Icon MPK.
| Arm | Type | Receives |
|---|---|---|
| Microprocessor-controlled knees (MPK) | Experimental | Other: College Park ICONSubjects will be fitted with the College Park ICON MPK and permitted to accommodate for 2 months prior to data collection. |
| Nonmicroprocessor-controlled knee (NMPK) | Active comparator | Other: Conventional NMPKSubjects will initially be evaluated walking on their conventional NMPK as a baseline prior to being fitted with the MPK. |
Who may qualify
- Ages
- 45 to 85 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- Unilateral, transfemoral amputation (any etiology)
- Residual limb length classified as standard (i.e., medium) to long
- Prosthesis user for at least 1 year prior to enrolling in the study
- K2-level classification while using their nonmicroprocessor-controlled knee (NMPK)
- Good sensation on their residual limb
Key exclusion criteria (2 listed)
- Bilateral leg amputations
- Individuals with a knee disarticulation
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| College Park ICONSubjects will be fitted and trained on the College Park ICON MPK. An accommodation period of 2 months will be provided prior to evaluation with the knee joint. | Other | Microprocessor-controlled knees (MPK) |
| Conventional NMPKSubjects will be tested walking with their conventional, mechanical prosthetic knee prior to being fitted with the MPK. | Other | Nonmicroprocessor-controlled knee (NMPK) |
Primary outcome
Walking speed
Time frame: To be measured before and immediately following the 2-month accommodation period of wearing the microprocessor-controlled knee the microprocessor-controlled knee (MPK)
Walking speed will be measured as participants walk on level ground at slow, normal and fast speeds.
Falls during walking
Time frame: To be determined before and during the 2-month accommodation period of wearing the the microprocessor-controlled knee (MPK)
The number of falls that occur while the subject is walking will be recorded in a daily diary.
PLUS-M
Time frame: To be measured before and immediately following the 2-month accommodation period of wearing the the microprocessor-controlled knee (MPK)
The Prosthetic Limb User Survey of Mobility (PLUS-M) will be used to determine the mobility of subjects before and after fitting with the MPK. Scores range from 12-60 points, and a higher score indicates greater mobility.
Prosthetic Knee Preference
Time frame: To be asked immediately following the 2-month accommodation period of wearing the the microprocessor-controlled knee (MPK)
Subjects will be asked which prosthetic knee they prefer at the completion of the study. For those that indicate preference for the the microprocessor-controlled knee (MPK), they will be permitted to keep it in their prosthesis. For those that prefer the nonmicroprocessor-controlled knee (NMPK), their prosthesis will be restored to the configuration prior to beginning the study.
2 secondary outcomes
ABC Scale
Time frame: To be administered before and immediately following the 2-month accommodation period of wearing the the microprocessor-controlled knee (MPK)
OPUS
Time frame: To be administered before and immediately following the 2-month accommodation period of wearing the the microprocessor-controlled knee (MPK)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 7 Oct 2026.
- Individual participant dataSharing planned: No. A Limited Dataset (LDS) will be created and shared pursuant to a Data Use Agreement (DUA) appropriately limiting use of the dataset and prohibiting the recipient from identifying or re-identifying (or taking steps to identify or re-identify) any individual whose data are included in the dataset. Results from this study will be freely disseminated via presentations at professional conferences and publications in scientific journals. Additionally, data acquired for this project will be shared with those investigators who make a formal request to the PI and can demonstrate a legitimate and justifiable cause for utilization of such data. All requests for these data will be discussed with the VA scientific program manager.
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Transfemoral Osseointegrated Prosthesis Limb-Load Symmetry Training
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Steven A Gard, PhD principal investigator
Jesse Brown VA Medical Center, Chicago, IL
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing College Park ICON and Conventional NMPK in people with Transfemoral Amputation and Limb Loss, run by VA Office of Research and Development at 2 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 7 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Rebecca Stine, MS ((312) 503-5726, rebecca.stine@va.gov), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Walking speed (time frame: To be measured before and immediately following the 2-month accommodation period of wearing the microprocessor-controlled knee the microprocessor-controlled knee (MPK)). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 7 Oct 2026.