Prosthetic Foot Testing for Amputation

Recruiting at 1 trial location

Overseen By Elizabeth G Halsne, PhD, CPO

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Seattle Institute for Biomedical and Clinical Research

Disqualifiers: Contralateral amputation, Neurological problems, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 7

100 Participants Needed

Trial Summary

What is the purpose of this trial?

Objective/Hypotheses and Specific Aims: The first aim of this proposal is to determine the effects of commercial prosthetic feet of varying stiffness on stability and falls-related outcomes in Veterans with TTA. The second aim is to determine whether a PFE can be used to predict stability and balance-confidence outcomes with corresponding commercial prosthetic feet. The third and final aim is to determine whether a brief trial of commercial prosthetic feet can predict longer-term stability and balance-confidence outcomes in Veterans with TTA. Study Design: The investigators will use a participant blinded cross-over study with repeated measurements in Veterans and Service members with TTA. Up to 50 participants will be enrolled at each of the two study sites VA Puget Sound and VA Minneapolis. Participants will complete up to 6 visits. After an initial assessment visit, participants will be assigned to the 'high' or 'low' mobility group, and then during visit 2 they will be randomized to use the PFE in three foot modes or the three corresponding actual (commercially available) feet during walking tests on difference surfaces in the laboratory (cross-slopes, inclines, even, and uneven ground). During visit 3 participants will repeat the procedures in the other condition (e.g., PFE if visit 2 included actual feet testing). At the end of visit 3 participants will be fit with one of the actual feet and wear it at home and in the community for approximately one week. At visit 4 participants will be fit with the next actual foot and repeat the 1 week use window. The same process will be followed for the final foot at visit 5, and the study foot will be returned at visit 6.

Do I need to stop taking my current medications for the trial?

The trial information does not specify whether you need to stop taking your current medications.

What data supports the effectiveness of the treatment involving commercially available prosthetic feet and a multiaxial prosthetic foot emulator for amputation?

The research shows that different types of prosthetic feet can lead to functional improvements in people with transtibial amputations, as measured by tests like the Amputee Mobility Predictor. Additionally, the six-minute walk test is a reliable way to assess the functional abilities of prosthesis users, which can help in prescribing the right prosthetic foot. ^{1 2 3 4 5}

Is the use of prosthetic feet generally safe for humans?

Research on prosthetic feet highlights the importance of safety during testing and training, with protocols in place to manage risks like loss of balance. Studies show that while there can be discomfort and pain, patient satisfaction is generally high, and safety measures like using a safety harness are recommended for additional protection. ^{2 6 7 8 9}

How does the treatment of commercially available prosthetic feet differ from other treatments for amputation?

This treatment is unique because it involves using commercially available prosthetic feet, which are tested for their mechanical properties like stiffness and ankle torque-angle characteristics. Unlike other treatments, this approach allows for the customization of prosthetic feet to match individual needs, potentially improving comfort and gait for amputees. ^{7 10 11 12 13}

Research Team

David C Morgenroth, MD

Principal Investigator

VA Puget Sound Health Care System

Eligibility Criteria

This trial is for Veterans with a below-knee amputation on one leg who've been walking with a prosthetic limb for at least six months. They must have a well-fitting prosthetic socket and be able to walk sufficiently for the trials. Those over 263lbs, with multiple amputations, or significant ambulation impairments are excluded.

Inclusion Criteria

I have one leg amputated below the knee.

My prosthetic socket fits comfortably.

I have been using a prosthetic limb for walking for over six months.

Exclusion Criteria

My weight is over 263lbs.

I am able to understand and communicate my consent to participate.

I am unable to make medical decisions for myself.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Initial Assessment and Randomization

Participants undergo an initial assessment and are assigned to mobility groups, followed by randomization to use the PFE or commercial feet

1 week

1 visit (in-person)

Cross-over Testing

Participants test the PFE and commercial feet under different walking conditions in a cross-over design

3 weeks

3 visits (in-person)

Home and Community Use

Participants use each commercial foot at home and in the community for approximately one week per foot

3 weeks

3 visits (in-person)

Follow-up

Participants are monitored for stability and balance-confidence outcomes after using the commercial feet

4 weeks

Treatment Details

Interventions

• Commercially available prosthetic feet
• Multiaxial Prosthetic Foot Emulator

Trial Overview The study tests how different stiffness in commercial prosthetic feet affects stability and fall-related outcomes. It involves up to six visits where participants use both a Prosthetic Foot Emulator (PFE) and actual commercial feet across various surfaces, followed by home use of these feet.

Participant Groups

Group I: Multiaxial Prosthetic Foot Emulator (PFE) Experimental Treatment 1 Intervention

The multiaxial Prosthetic Foot Emulator (PFE) is a customizable robotic prosthetic foot that can mimic commercial feet to predict how prosthesis users will respond to candidate feet. Participants will walk with the PFE using three different modes (emulating three commercial feet) under different walking conditions.

Group II: Commercially available prosthetic feet Active Control 1 Intervention

Participants will walk under different walking conditions using three different commercial prosthetic feet.

Who Is Running the Clinical Trial?

Seattle Institute for Biomedical and Clinical Research

Lead Sponsor

Trials

55

Recruited

13,700+

VA Puget Sound Health Care System

Collaborator

Trials

67

Recruited

225,000+

Minneapolis Veterans Affairs Medical Center

Collaborator

Trials

77

Recruited

355,000+

University of Chicago

Collaborator

Trials

1,086

Recruited

844,000+

Findings from Research

In a study involving 10 individuals with unilateral transtibial limb loss, standardized functional prosthetic gait training did not show significant improvements in self-report measures or performance-based tests, except for the Amputee Mobility Predictor (AMPPRO) in those with peripheral vascular disease (PVD).

The Proprio foot demonstrated significant differences in mobility outcomes compared to other prosthetic feet, particularly in the AMPPRO and 6-minute walk test (6MWT), highlighting its potential benefits for users with PVD.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Application of self-report and performance-based outcome measures to determine functional differences between four categories of prosthetic feet. Gailey, RS., Gaunaurd, I., Agrawal, V., et al.[2022]

In a study of 60 adults with transtibial amputations, mobility scores were the lowest, indicating challenges in ambulation and transfers, with average scores of 55.3 and 64.6 respectively, despite all participants using a prosthesis for at least 6 months.

Psychosocial responses were rated highest, with perceived responses scoring 86.6, suggesting that emotional and social aspects of living with a prosthesis may be more positively perceived than functional mobility, which contrasts with typical expectations in rehabilitation.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Health related quality of life in patients with dysvascular transtibial amputation. Harness, N., Pinzur, MS.[2022]

The instrumented version of the Four Square Step Test (FSST) demonstrated good to excellent test-retest reliability for measuring stepping patterns in 20 adults with unilateral transfemoral amputation, indicating it is a reliable tool for assessing functional performance.

Significant differences were found between two microprocessor knees, suggesting that one knee provided functional improvements over the other, which can help guide decisions in prosthetic selection for better mobility.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Instrumented Four Square Step Test in Adults with Transfemoral Amputation: Test-Retest Reliability and Discriminant Validity between Two Types of Microprocessor Knees. Gouelle, A., Highsmith, MJ.[2022]

A study of 120 unilateral transtibial prosthesis users found that the six-minute walk test (6MWT) and one-leg standing test on prosthesis (OLSTP) can effectively predict the functional K-level of patients, which is crucial for appropriate prosthesis prescription.

Using a simple classification rule based on 6MWT results, the study achieved nearly 90% sensitivity and specificity in distinguishing between different K-levels, suggesting these tests could enhance clinical decision-making in rehabilitation programs.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Establishing K-levels and prescribing transtibial prostheses using six-minute walk test and one-leg standing test on prosthesis: a retrospective audit. Majdič, N., Vidmar, G., Burger, H.[2022]

The pressure casting technique (PCAST) for creating transtibial prosthetic sockets was successfully used on 13 adult volunteers, with a 62% success rate in fitting the prosthesis, indicating its potential for use in developing countries with limited resources.

Participants who used the prosthesis for an average of 167 days reported high satisfaction levels and showed significant improvements in physical function, such as faster timed up-and-go and longer six-minute walk distances, suggesting that PCAST can enhance mobility for individuals with unilateral amputations.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Pressure casting technique for transtibial prosthetic socket fit in developing countries. Lee, PV., Lythgo, N., Laing, S., et al.[2022]

A structured protocol for testing lower limb prostheses emphasizes safety, requiring users to meet specific graded safety levels before progressing to more challenging environments.

This approach aims to reduce the risk of falls and injuries, thereby enhancing user confidence and overall experience with active prosthetic legs.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Design of a stepwise safety protocol for lower limb prosthetic risk management in a clinical investigation. Thesleff, A., Ahkami, B., Anderson, J., et al.[2022]

In a study involving 141 patients using trans-tibial prostheses developed by the ICRC, quality benchmarks were established to assess patient compliance and technical performance, focusing on factors like walking distance and socket fit.

The benchmarks set high standards for patient satisfaction (90% compliance) and low levels of discomfort (10%) and pain (10%), indicating a strong emphasis on both user experience and the technical reliability of the prosthetic devices.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Quality benchmark for trans-tibial prostheses in low-income countries. Jensen, JS., Nilsen, R., Zeffer, J.[2022]

A study involving 526 individuals compared the functional mobility of different prosthetic feet, revealing that advanced designs can offer similar benefits to traditional shock-absorbing feet.

The findings suggest that focusing on the functional performance of prosthetic feet, rather than just their mechanical features, may lead to improved outcomes for users.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

OASIS 2: Mobility differences with specific prosthetic feet across procedure codes. Miller, TA., Campbell, JH., England, DL., et al.[2022]

The newly designed bypass socket allows able-bodied researchers to safely wear a leg prosthesis for testing, facilitating the development of lower limb prosthetic technologies.

This 3D-printed bypass socket is cost-effective and time-efficient, enabling better evaluation of prosthetic components while ensuring safety through features like an open-socket design for electromyography and the recommendation of a safety harness.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Design of an open-source transfemoral, bypass socket. Oberg, V., Thesleff, A., Ortiz-Catalan, M.[2021]

In a study comparing methods to reduce shear forces during mechanical testing of prosthetic feet, a low-friction interface was found to be a cost-effective alternative to a roller plate, with similar effects on stiffness measurements.

The testing showed consistent results across multiple sessions, indicating that the methods used provide reliable data for evaluating the mechanical properties of prosthetic feet.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effects of shear force reduction during mechanical testing and day-to-day variation on stiffness of commercial prosthetic feet: a technical note. Halsne, EG., Turner, AT., Curran, CS., et al.[2022]

A robotic prosthetic foot emulator (PFE) can accurately replicate the effective ankle stiffness of various commercial prosthetic forefeet, achieving an average accuracy within 1% of the actual feet tested.

This technology allows prosthesis users to trial different foot types based on their mechanical characteristics, potentially improving the decision-making process for prosthetic foot selection and enhancing user satisfaction.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Emulating the Effective Ankle Stiffness of Commercial Prosthetic Feet Using a Robotic Prosthetic Foot Emulator. Halsne, EG., Curran, CS., Caputo, JM., et al.[2022]

Testing of nine different commercially available SACH (Solid Ankle Cushion Heel) feet has been conducted to enhance testing methods and durability standards for artificial feet.

Further research is needed to better understand how the functions of these artificial feet relate to different amputation levels and activity levels, which is crucial for improving comfort and gait for amputees.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Physical response of SACH feet under laboratory testing. Daher, RL.[2004]

Miniature triaxial shoe-borne load cells effectively analyze the gait of both normal individuals and below-knee amputees, allowing for the identification of gait misalignments and issues related to the prosthetic fit.

This method not only helps in assessing functional mobility through center of pressure calculations but also aids in diagnosing and correcting problems in the amputee's stump, enhancing overall gait performance.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Normal and pathological human gait analysis using miniature triaxial shoe-borne load cells. Ranu, HS.[2013]

References

1. United States pubmed.ncbi.nlm.nih.gov

Application of self-report and performance-based outcome measures to determine functional differences between four categories of prosthetic feet. [2022]

2. United States pubmed.ncbi.nlm.nih.gov

Health related quality of life in patients with dysvascular transtibial amputation. [2022]

3. Switzerland pubmed.ncbi.nlm.nih.gov

Instrumented Four Square Step Test in Adults with Transfemoral Amputation: Test-Retest Reliability and Discriminant Validity between Two Types of Microprocessor Knees. [2022]

4. England pubmed.ncbi.nlm.nih.gov

Establishing K-levels and prescribing transtibial prostheses using six-minute walk test and one-leg standing test on prosthesis: a retrospective audit. [2022]

5. United States pubmed.ncbi.nlm.nih.gov

Pressure casting technique for transtibial prosthetic socket fit in developing countries. [2022]

6. United States pubmed.ncbi.nlm.nih.gov

Design of a stepwise safety protocol for lower limb prosthetic risk management in a clinical investigation. [2022]

7. France pubmed.ncbi.nlm.nih.gov

Quality benchmark for trans-tibial prostheses in low-income countries. [2022]

8. England pubmed.ncbi.nlm.nih.gov

OASIS 2: Mobility differences with specific prosthetic feet across procedure codes. [2022]

9. United States pubmed.ncbi.nlm.nih.gov

Design of an open-source transfemoral, bypass socket. [2021]

10. France pubmed.ncbi.nlm.nih.gov

Effects of shear force reduction during mechanical testing and day-to-day variation on stiffness of commercial prosthetic feet: a technical note. [2022]

11. United States pubmed.ncbi.nlm.nih.gov

Emulating the Effective Ankle Stiffness of Commercial Prosthetic Feet Using a Robotic Prosthetic Foot Emulator. [2022]

12. United States pubmed.ncbi.nlm.nih.gov

Physical response of SACH feet under laboratory testing. [2004]

13. United States pubmed.ncbi.nlm.nih.gov

Normal and pathological human gait analysis using miniature triaxial shoe-borne load cells. [2013]