Prosthetic Socket Design for Amputees

Recruiting at 1 trial location

Overseen By William Anderst, PhD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of Pittsburgh

Disqualifiers: Pregnancy, Osteoporosis, Radiation exposure

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

Approved in 6 Jurisdictions This treatment is already approved in other countries

Compensation: Varies

Number of Visits: 9

Duration: 8-10 weeks

30 Participants Needed

Trial Summary

What is the purpose of this trial?

This study will investigate the effects of specific standardized modifications to trans-femoral prosthetic sockets in a randomized within-subject design. This is in preparation for a subsequently planned clinical trial to validate the findings by implementing them into a fitting method for individual sockets.

Do I need to stop 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 Trans-femoral prosthetic socket?

The research suggests that both the quadrilateral and ischial containment socket designs have been used successfully for many years, with each having a legitimate place in treating patients with transfemoral amputations. Additionally, the development of the subischial socket aims to improve comfort and quality of life for users, indicating ongoing efforts to enhance socket design. ^{1 2 3 4 5}

Is the prosthetic socket design for amputees generally safe for humans?

The research indicates that different prosthetic socket designs, like the quadrilateral and ischial containment sockets, have been used for many years and are generally considered safe for humans. They have more similarities than differences, and both have a legitimate place in treating patients with transfemoral amputations. ^{1 3 4 6 7}

How is the Trans-femoral prosthetic socket treatment unique for amputees?

The Trans-femoral prosthetic socket treatment is unique because it includes various designs like the Direct Socket, which is shaped and laminated directly on the residual limb in a single visit, and the Sub-Ischial Socket, which has lower trim lines for improved comfort and function. These innovations aim to address common issues like discomfort and restricted function associated with traditional socket designs. ^{1 2 3 4 8}

Research Team

William Anderst, PhD

Principal Investigator

University of Pittsburgh

Eligibility Criteria

This trial is for individuals aged 18-80 who use a transfemoral prosthesis, can walk unassisted on a treadmill, and weigh less than 125 kg. It's not suitable for those with high radiation exposure, pregnant women, or anyone clinically diagnosed with osteoporosis.

Inclusion Criteria

I use a prosthetic leg that attaches at the thigh.

I can walk by myself on a treadmill.

Body weight less than 125 kg

Exclusion Criteria

I have been exposed to high levels of radiation in the past.

I have been diagnosed with osteoporosis.

You are pregnant.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants undergo testing with unmodified and 8 modified socket designs in a randomized order

8-10 weeks

9 visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

Treatment Details

Interventions

• Trans-femoral prosthetic socket

Trial Overview The study is testing specific standardized changes to the design of transfemoral prosthetic sockets. Participants will experience different socket modifications in a randomized order to prepare for future trials on individual fitting methods.

Participant Groups

Group I: Unmodified Socket + 8 Socket Modifications in Random Order Experimental Treatment 1 Intervention

The sequence of the 9 different interventions (original socket and 8 versions derived from it) is randomized for each participant. The number of participants is smaller than the number of possible permutations. Therefore the enacted ordering is randomly selected from the pool of possible orderings. Participants walk for less than 10 minutes with every socket type while data is being collected.

Trans-femoral prosthetic socket is already approved in European Union, United States, Canada, Japan, China, Switzerland for the following indications:

Approved in European Union as Transfemoral Prosthetic Socket for:

• Transfemoral amputations

Approved in United States as Transfemoral Prosthetic Socket for:

• Transfemoral amputations

Approved in Canada as Transfemoral Prosthetic Socket for:

• Transfemoral amputations

Approved in Japan as Transfemoral Prosthetic Socket for:

• Transfemoral amputations

Approved in China as Transfemoral Prosthetic Socket for:

• Transfemoral amputations

Approved in Switzerland as Transfemoral Prosthetic Socket for:

• Transfemoral amputations

Who Is Running the Clinical Trial?

University of Pittsburgh

Lead Sponsor

Trials

1,820

Recruited

16,360,000+

United States Department of Defense

Collaborator

Trials

940

Recruited

339,000+

Findings from Research

Both the quadrilateral and ischial containment sockets are valid options for patients with transfemoral amputations, with each design having its own advantages and applications.

Despite claims of superiority for the ischial containment socket, there is limited scientific evidence supporting its benefits over the quadrilateral socket, suggesting that both designs share more similarities than differences in their effectiveness.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Current transfemoral sockets. Schuch, CM., Pritham, CH.[2022]

A study involving 47 transfemoral prosthetic users showed that the Direct Socket interface significantly improved quality of life, comfort, and mobility compared to their previous prostheses, with 36 subjects completing the 6-month follow-up.

Participants reported enhanced stability, suspension, and overall comfort with the Direct Socket, along with improved mobility as indicated by reduced reliance on assistive devices, suggesting this method is a promising alternative to traditional prosthetic fittings.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Clinical Outcome of Transfemoral Direct Socket Interface (Part 2). Walker, J., Marable, WR., Smith, C., et al.[2023]

The transfemoral socket is essential for ensuring comfort and functionality in prosthetic limbs, regardless of the technology used in other components like knees and feet.

The article reviews different socket designs, specifically quadrilateral and ischial containment, and discusses various suspension options to optimize the fit and performance of the prosthesis.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Transfemoral socket design and suspension options. Kapp, SL.[2013]

The new subischial socket design improved comfort for both transfemoral prosthesis users compared to traditional ischial containment sockets, as evaluated through comfort scores.

Functional performance, measured by gait analysis and clinical outcome tests, was generally comparable between the subischial socket and ischial containment sockets, indicating that while comfort improved, overall function remained similar.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Northwestern University Flexible Subischial Vacuum Socket for persons with transfemoral amputation: Part 2 Description and Preliminary evaluation. Fatone, S., Caldwell, R.[2022]

The study developed rectification maps from 30 cast pairs of prosthetic sockets, showing that material was mainly removed from the proximal-lateral and posterior regions to improve fit for transfemoral amputees.

Using these rectification maps, a template was created that allowed for the fabrication of check sockets for 15 patients, resulting in a reasonable initial fit with only minor adjustments needed, indicating the template's effectiveness in teaching and central fabrication of the new socket design.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Quantification of rectifications for the Northwestern University Flexible Sub-Ischial Vacuum Socket. Fatone, S., Johnson, WB., Tran, L., et al.[2022]

A new system was developed to measure pressure at the stump-socket interface, revealing that maximum pressures reached 34 kPa while standing and 95 kPa during walking in two trans-femoral amputee volunteers.

The ischial containment socket provided a more evenly distributed pressure profile compared to the quadrilateral socket, which had higher pressures at the proximal brim, suggesting potential benefits for comfort and fit in prosthetic design.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Stump-socket interface pressure as an aid to socket design in prostheses for trans-femoral amputees--a preliminary study. Lee, VS., Solomonidis, SE., Spence, WD.[2017]

The adjustable subischial transfemoral prosthesis was rated significantly more comfortable and functional than conventional sockets by participants, with an average comfort score of 40.9 compared to 32.8 (P=.004).

In a 2-week trial involving 18 participants, there were no adverse events such as falls or skin breakdown, and 61% of participants continued to use the adjustable prosthesis regularly after the trial, indicating its safety and effectiveness.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A Prospective Assessment of an Adjustable, Immediate Fit, Subischial Transfemoral Prosthesis. Dillingham, TR., Kenia, JL., Shofer, FS., et al.[2022]

In a study of 12 transfemoral amputees, those using the ischial-ramal containment (IRC) socket reported significantly better comfort and stability compared to those using the quadrilateral (QL) socket, particularly in sitting comfort and lumbar support.

Despite the IRC socket providing a more comfortable experience and better femur positioning, it did not show superior metabolic efficiency in gait compared to the QL socket, indicating that while the IRC socket may enhance comfort, it does not improve oxygen consumption during walking.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Subjective evaluations and objective measurements of the ischial-ramal containment prosthesis. Hachisuka, K., Umezu, Y., Ogata, H., et al.[2019]

References

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

Current transfemoral sockets. [2022]

2. Canada pubmed.ncbi.nlm.nih.gov

Clinical Outcome of Transfemoral Direct Socket Interface (Part 2). [2023]

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

Transfemoral socket design and suspension options. [2013]

4. France pubmed.ncbi.nlm.nih.gov

Northwestern University Flexible Subischial Vacuum Socket for persons with transfemoral amputation: Part 2 Description and Preliminary evaluation. [2022]

5. France pubmed.ncbi.nlm.nih.gov

Quantification of rectifications for the Northwestern University Flexible Sub-Ischial Vacuum Socket. [2022]

6. England pubmed.ncbi.nlm.nih.gov

Stump-socket interface pressure as an aid to socket design in prostheses for trans-femoral amputees--a preliminary study. [2017]

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

A Prospective Assessment of an Adjustable, Immediate Fit, Subischial Transfemoral Prosthesis. [2022]

8. Japan pubmed.ncbi.nlm.nih.gov

Subjective evaluations and objective measurements of the ischial-ramal containment prosthesis. [2019]