Vacuum Suspension: Effects on Tissue Oxygenation, Activity and Fit

This study has been completed.
Sponsor:
Information provided by (Responsible Party):
Department of Veterans Affairs
ClinicalTrials.gov Identifier:
NCT00117793
First received: July 1, 2005
Last updated: July 28, 2014
Last verified: July 2014
  Purpose

The fit of the residual limb within a prosthetic socket is a primary concern for many amputees. A poor fit can lead to skin irritation, tissue breakdown, and pain. Further, amputees with diabetes or vascular dysfunction often have difficulty maintaining healthy residual limb tissue; a condition that could be mitigated by the application of negative pressure (i.e., vacuum suspension). The aim of this research is to characterize the residual limb response to a vacuum suspension system and to measure prosthetic performance in comparison to a typical suction suspension system.

The proposed research plan involves two sets of human subject experiments: (1) prospective, randomized cross-over study to quantify performance of a vacuum suspension system as compared to a total surface bearing suction socket in terms of pistoning, maintaining limb volume, step counts, and subjective measures of fit and (2) measurement of transcutaneous oxygen tension as a function of vacuum pressure.


Condition Intervention
Amputation
Diabetes
Leg Injuries
Traumatic Amputations
Device: Total Surface Bearing Suction Socket
Device: Vacuum assisted socket system

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Crossover Assignment
Masking: Single Blind (Subject)
Primary Purpose: Treatment
Official Title: Vacuum Suspension: Effects on Tissue Oxygenation, Activity and Fit

Resource links provided by NLM:


Further study details as provided by Department of Veterans Affairs:

Primary Outcome Measures:
  • Limb Volume [ Time Frame: Measurements were taken after wearing the study prostheses for three weeks ] [ Designated as safety issue: No ]
  • Activity Level [ Time Frame: Two weeks ] [ Designated as safety issue: No ]
    Total number of steps during a two week period ending in the fourth week for each study prosthesis (PIN and VASS).

  • Limb Pistoning [ Time Frame: Measurements were taken after wearing the study prosthesis for three weeks ] [ Designated as safety issue: No ]
    Limb pistoning is the change in the resultant distance between the prosthetic-side knee joint marker triad and the residual limb thigh triad measured using a 12-camera motion analysis system while subjects weighted and un-weighted their prosthesis standing in place.


Secondary Outcome Measures:
  • Residual Limb Health (PEQ Scale) [ Time Frame: Measurements were taken after wearing the study prosthesis for four weeks ] [ Designated as safety issue: No ]
    Qualitative differences between the study limbs were assessed using the Prosthesis Evaluation Questionnaire (PEQ). This standardized, self-report instrument is specific to persons with lower limb amputations and is used to evaluate prosthetic care with regard to prescription and prosthesis-related quality of life. The Residual Limb Health scale examines: sweat, smell, volume changes, rashes, ingrown hairs, and blisters. The scale is scored from 0 to 100 where 100 indicates the best outcome (i.e., most healthful).

  • Ambulation (PEQ Scale) [ Time Frame: Measurements were taken after wearing the study prosthesis for four weeks ] [ Designated as safety issue: No ]
    Qualitative differences between the study limbs were assessed using the Prosthesis Evaluation Questionnaire (PEQ). This standardized, self-report instrument is specific to persons with lower limb amputations and is used to evaluate prosthetic care with regard to prescription and prosthesis-related quality of life. The Ambulation scale queries the ability to walk in general, in close spaces, on stairs and ramps, in urban environments, and on slippery surfaces. The scale is scored from 0 to 100 where 100 indicates the best outcome (i.e., easiest to walk on).

  • Frustration (PEQ Scale) [ Time Frame: Measurements were taken after wearing the study prosthesis for four weeks ] [ Designated as safety issue: No ]
    Qualitative differences between the study limbs were assessed using the Prosthesis Evaluation Questionnaire (PEQ). This standardized, self-report instrument is specific to persons with lower limb amputations and is used to evaluate prosthetic care with regard to prescription and prosthesis-related quality of life. Frustration was assessed by frequency of occurrence and rating. The scale is scored from 0 to 100 where 100 indicates the best outcome (i.e., least frustrating).


Enrollment: 20
Study Start Date: August 2005
Study Completion Date: September 2008
Primary Completion Date: September 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: Arm 1
Current clinical practice
Device: Total Surface Bearing Suction Socket
Current clinical practice
Experimental: Arm 2
Novel socket system
Device: Vacuum assisted socket system
Novel socket system

Detailed Description:

A proper fitting prosthetic socket provides the amputee with a comfortable system allowing them to pursue many of their desired vocational and recreational goals. Unfortunately, many amputees live with an ill-fitting socket and can experience limb pistoning within the socket, which in turn may result in skin irritation, tissue breakdown, discomfort, and a reduction in activity. One of the key factors affecting fit is intraday residual limb volume changes. For an amputee with dysvascular conditions, the implications of a poor fitting socket are exacerbated by poor circulation, reduced healing potential and the compressive forces exerted by their prosthesis.

Vacuum suspension systems may have the potential to alleviate these conditions for healthy and dysvascular amputees. The purported benefits of vacuum suspension systems include, but are not limited to: improved suspension (reduction in the amount of pistoning), maintenance of limb volume throughout the day, and increased tissue oxygenation to the residual limb.

Our first objective is to characterize performance, as related to socket fit, of a vacuum suspension system using objective and subjective measures. We will do this by conducting a within-subject experiment to measure pistoning in three dimensions while walking, overall and regional changes in limb volume before and after a thirty-minute treadmill walk, mobility (step counts) and the perception of socket fit (questionnaire) as a function of prosthetic prescription (vacuum suspension system vs. total surface bearing suction socket).

Our second objective is to determine the effect of pressures within a prosthetic socket on residual limb transcutaneous oxygen tension (tcpO2) levels. We will conduct laboratory-based, in situ testing to determine how the transcutaneous oxygen tension levels, at six sites on the residual limb, respond to pressures simulating those within a vacuum suspension system and a total surface bearing suction socket.

The proposed research will allow us to understand how suspension systems influence prosthetic socket fit and residual limb tissue health and to formulate a knowledge base on two suspension systems providing prosthetists and clinicians the objective data to make better prescription decisions. In addition, the methods utilized in this study (e.g., a residual limb limb volume scanner and assessing dynamic pistoning) can be used to study current and novel suspension systems, liners, and prosthetic socket designs to provide a standard for comparison.

  Eligibility

Ages Eligible for Study:   18 Years to 70 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Over 18 and less than 70 years of age,
  • Have a below knee amputation involving only one side,
  • If the cause of amputation was for traumatic reasons and do not have diabetes or a vascular condition, the amputation must have occurred at least six months ago and the potential subject must have worn a prosthesis for at least four months,
  • If the cause of amputation was for diabetes or vascular reasons, the potential subject must have been fit with a prosthesis and have worn it for at least one year,
  • Wear the prosthesis for at least 6 hours a day,
  • Able to walk without a cane, crutches, or a walker,
  • Are moderately active enough to walk at a steady pace for at least 30 minutes.

Exclusion Criteria:

  • Have pain in legs or any condition that interferes with walking.
  • Have an ulcer on the residual limb,
  • If potential subject had an amputation because of a tumor or an infection, no longer have an active tumor or undergoing treatment for a tumor,
  • Have fallen within the last 3 months.
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00117793

Locations
United States, Washington
VA Puget Sound Health Care System, Seattle
Seattle, Washington, United States, 98108
Sponsors and Collaborators
Investigators
Principal Investigator: Glenn K. Klute, PhD VA Puget Sound Health Care System, Seattle
  More Information

No publications provided by Department of Veterans Affairs

Additional publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: Department of Veterans Affairs
ClinicalTrials.gov Identifier: NCT00117793     History of Changes
Other Study ID Numbers: A3666
Study First Received: July 1, 2005
Results First Received: October 24, 2013
Last Updated: July 28, 2014
Health Authority: United States: Federal Government

Keywords provided by Department of Veterans Affairs:
Amputee
Artificial limbs
Gait
Walking

Additional relevant MeSH terms:
Amputation, Traumatic
Leg Injuries
Wounds and Injuries

ClinicalTrials.gov processed this record on August 28, 2014