Effect of a Microprocessor-controlled Prosthetic Knee Joint on K2 Level Ambulators

NCT ID: NCT07103798

Last Updated: 2026-01-08

Basic Information

• Recruitment Status: NOT_YET_RECRUITING
• Clinical Phase: NA
• Total Enrollment: 20 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2026-03-02
• Study Completion Date: 2027-12-31

Brief 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. 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.

Conditions

Transfemoral Amputation; Limb Loss; Limb Absence

Study Design

• Allocation Method: NON_RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: TREATMENT
• Blinding Strategy: NONE

Study Groups

MPK

Subjects will be fitted with the College Park ICON MPK and permitted to accommodate for 2 months prior to data collection.

Group Type: EXPERIMENTAL

College Park ICON

Intervention Type: OTHER

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.

NMPK

Subjects will initially be evaluated walking on their conventional NMPK as a baseline prior to being fitted with the MPK.

Group Type: ACTIVE_COMPARATOR

Conventional NMPK

Intervention Type: OTHER

Subjects will be tested walking with their conventional, mechanical prosthetic knee prior to being fitted with the MPK.

Interventions

College Park ICON

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.

Intervention Type: OTHER

Conventional NMPK

Subjects will be tested walking with their conventional, mechanical prosthetic knee prior to being fitted with the MPK.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Unilateral, transfemoral amputation (any etiology).
• Age from 45-85 years.
• 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 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.

Exclusion Criteria

• Bilateral leg amputations.
• Individuals with a knee disarticulation.

• Minimum Eligible Age: 45 Years
• Maximum Eligible Age: 85 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

VA Office of Research and Development

FED

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Steven A Gard, PhD

Role: PRINCIPAL_INVESTIGATOR

Jesse Brown VA Medical Center, Chicago, IL

Locations

Jesse Brown VA Medical Center, Chicago, IL

Chicago, Illinois, United States

Edward Hines Jr. VA Hospital, Hines, IL

Hines, Illinois, United States

Countries

United States

Central Contacts

Rebecca Stine, MS

Role: CONTACT

rebecca.stine@va.gov

(312) 503-5726

Steven A Gard, PhD

Role: CONTACT

steven.gard@va.gov

(312) 503-5718

Facility Contacts

Rebecca Stine, MS

Role: primary

rebecca.stine@va.gov

(312) 503-5726

Steven A Gard, PhD

Role: backup

steven.gard@va.gov

(312) 503-5718

Rebecca Stine, MS

Role: primary

rebecca.stine@va.gov

312-503-5726

Steven A Gard, PhD

Role: backup

steven.gard@va.gov

3125035718

Other Identifiers

RX005610

Identifier Type: OTHER_GRANT

Identifier Source: secondary_id

RRD2-005-24W

Identifier Type: -

Identifier Source: org_study_id