Clinical trial NCT00117793: Vacuum Suspension: Effects on Tissue Oxygenation, Activity and Fit
Official title: Vacuum Suspension: Effects on Tissue Oxygenation, Activity and Fit
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Amputation
Diabetes
Leg Injuries
Traumatic Amputations
Keywords: Amputee
Artificial limbs
Gait
Walking
Lead sponsor: VA Office of Research and Development
Sponsor class: FED
First posted: 2005-07-08
Enrollment: 20
Sex: ALL
Minimum age (years): 18
Maximum age (years): 70
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: TREATMENT

Brief summary: 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.

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 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.

Primary outcomes:
measure: Limb Volume
timeFrame: Measurements were taken after wearing the study prostheses for three weeks
measure: Activity Level
timeFrame: Two weeks
measure: Limb Pistoning
timeFrame: Measurements were taken after wearing the study prosthesis for three weeks
Secondary outcomes:
measure: Residual Limb Health (PEQ Scale)
timeFrame: Measurements were taken after wearing the study prosthesis for four weeks
measure: Ambulation (PEQ Scale)
timeFrame: Measurements were taken after wearing the study prosthesis for four weeks
measure: Frustration (PEQ Scale)
timeFrame: Measurements were taken after wearing the study prosthesis for four weeks
Other outcomes:
Locations:
city: Seattle
country: United States
facility: VA Puget Sound Health Care System, Seattle
state: Washington
Study officials:
affiliation: VA Puget Sound Health Care System, Seattle
name: Glenn K. Klute, PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Klute GK, Berge JS, Biggs W, Pongnumkul S, Popovic Z, Curless B. Vacuum-assisted socket suspension compared with pin suspension for lower extremity amputees: effect on fit, activity, and limb volume. Arch Phys Med Rehabil. 2011 Oct;92(10):1570-5. doi: 10.1016/j.apmr.2011.05.019.