An interventional study of College Park ICON and Conventional NMPK in Transfemoral Amputation, Limb Loss and Limb Absence, sponsored by VA Office of Research and Development. Not yet recruiting at 2 sites in United States. Open to participants aged 45 Years to 85 Years. Per ClinicalTrials.gov, last updated 2026-10-07.
Sponsored by VA Office of Research and Development · Not applicable, Interventional, and Treatment
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.
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.
VA Office of Research and Development is the lead sponsor of 1,733 studies on the registry; 396 are open to participants now.
Of its 206 completed or terminated interventional studies of FDA-regulated products, 180 (87%) have results posted.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Subjects will be fitted with the College Park ICON MPK and permitted to accommodate for 2 months prior to data collection.
Other: College Park ICON
Subjects will initially be evaluated walking on their conventional NMPK as a baseline prior to being fitted with the MPK.
Other: Conventional NMPK
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.
Subjects will be tested walking with their conventional, mechanical prosthetic knee prior to being fitted with the MPK.
Walking speed
Walking speed will be measured as participants walk on level ground at slow, normal and fast speeds.
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)
Falls during walking
The number of falls that occur while the subject is walking will be recorded in a daily diary.
Time frame: 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.
Time frame: 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.
Time frame: To be asked immediately following the 2-month accommodation period of wearing the the microprocessor-controlled knee (MPK)
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.
Time frame: 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.
Time frame: To be administered before and immediately following the 2-month accommodation period of wearing the the microprocessor-controlled knee (MPK)
Plan to share: 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.
No publications or documents are linked to this record.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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