Trial Outcomes & Findings for Vacuum Suspension: Effects on Tissue Oxygenation, Activity and Fit (NCT NCT00117793)

NCT ID: NCT00117793

Last Updated: 2014-08-15

Results Overview

• Recruitment status: COMPLETED
• Study phase: NA
• Target enrollment: 20 participants
• Primary outcome timeframe: Measurements were taken after wearing the study prostheses for three weeks
• Results posted on: 2014-08-15

Participant Flow

Recruitment for this study was conducted at the VA Puget Sound Health Care System (Seattle VA hospital). Recruitment began on March 28, 2007. The study was closed to enrollment on March 30, 2012.

The prostheses used in this study were built and aligned by a certified and licensed prosthetist prior to beginning starting the protocol. 20 individuals gave informed consent but 3 withdrew prior to starting: 1 had contralateral knee surgery, 1 became a bi-lateral amputee, and 1 was withdrawn by the participant's physician.

Participant milestones

Measure	Entire Study Population This is a randomized cross-over study. Each participant wore both study prostheses: (1) a total surface bearing socket with a vacuum-assisted suspension system (VASS) and (2) a modified patellar tendon bearing socket with a pin lock suspension system (PIN). Subjects were randomized, provided with one of two study prostheses, and asked to wear it for three weeks. Data was then collected during laboratory visit one, and, following one more week of wearing the first study prosthesis, during laboratory visit two. Participants were then provided with the second study intervention and asked to wear it for three weeks. Data was then collected during laboratory visit three, and, following one more week of wearing the second study intervention, during laboratory visit four. Data was not collected on the order in which participants received each study intervention
Overall Study STARTED	17
Overall Study COMPLETED	5
Overall Study NOT COMPLETED	12

Reasons for withdrawal

Measure

Entire Study Population This is a randomized cross-over study. Each participant wore both study prostheses: (1) a total surface bearing socket with a vacuum-assisted suspension system (VASS) and (2) a modified patellar tendon bearing socket with a pin lock suspension system (PIN). Subjects were randomized, provided with one of two study prostheses, and asked to wear it for three weeks. Data was then collected during laboratory visit one, and, following one more week of wearing the first study prosthesis, during laboratory visit two. Participants were then provided with the second study intervention and asked to wear it for three weeks. Data was then collected during laboratory visit three, and, following one more week of wearing the second study intervention, during laboratory visit four. Data was not collected on the order in which participants received each study intervention

Overall Study Withdrawal by Subject

12

Baseline Characteristics

Vacuum Suspension: Effects on Tissue Oxygenation, Activity and Fit

Baseline characteristics by cohort

Measure	Entire Study Population n=5 Participants Includes participants randomized to receive PIN first and VASS first.
Age, Categorical <=18 years	0 Participants n=5 Participants
Age, Categorical Between 18 and 65 years	5 Participants n=5 Participants
Age, Categorical >=65 years	0 Participants n=5 Participants
Age, Continuous	56 years STANDARD_DEVIATION 9 • n=5 Participants
Sex: Female, Male Female	0 Participants n=5 Participants
Sex: Female, Male Male	5 Participants n=5 Participants
Amputation etiology Diabetic	1 Participants n=5 Participants
Amputation etiology Traumatic	4 Participants n=5 Participants
Years post-amputation	13 Years STANDARD_DEVIATION 15 • n=5 Participants
Weight	84 kg STANDARD_DEVIATION 11 • n=5 Participants
Height	1.78 m STANDARD_DEVIATION 0.11 • n=5 Participants

PRIMARY outcome

Timeframe: Measurements were taken after wearing the study prostheses for three weeks

Population: The number of participants for analysis is equal to the number of participants who completed the study protocol.

Outcome measures

Measure	PIN Suspension n=5 Participants A modified patellar tendon bearing socket with a pin lock suspension system (PIN)	VASS Suspension n=5 Participants A total surface bearing socket with a vacuum-assisted suspension system (VASS).
Limb Volume	0.68 liters Standard Deviation .14	0.72 liters Standard Deviation .13

PRIMARY outcome

Timeframe: Two weeks

Population: The number of participants for analysis is equal to the number of participants who completed the study protocol.

Total number of steps during a two week period ending in the fourth week for each study prosthesis (PIN and VASS).

Outcome measures

Measure	PIN Suspension n=5 Participants A modified patellar tendon bearing socket with a pin lock suspension system (PIN)	VASS Suspension n=5 Participants A total surface bearing socket with a vacuum-assisted suspension system (VASS).
Activity Level	73 steps (in thousands) Standard Deviation 18	38 steps (in thousands) Standard Deviation 9

PRIMARY outcome

Timeframe: Measurements were taken after wearing the study prosthesis for three weeks

Population: The number of participants for analysis is equal to the number of participants who completed the study protocol.

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.

Outcome measures

Measure	PIN Suspension n=5 Participants A modified patellar tendon bearing socket with a pin lock suspension system (PIN)	VASS Suspension n=5 Participants A total surface bearing socket with a vacuum-assisted suspension system (VASS).
Limb Pistoning	6 mm Standard Deviation 4	1 mm Standard Deviation 3

SECONDARY outcome

Timeframe: Measurements were taken after wearing the study prosthesis for four weeks

Population: The number of participants for analysis is equal to the number of participants who completed the study protocol.

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).

Outcome measures

Measure	PIN Suspension n=5 Participants A modified patellar tendon bearing socket with a pin lock suspension system (PIN)	VASS Suspension n=5 Participants A total surface bearing socket with a vacuum-assisted suspension system (VASS).
Residual Limb Health (PEQ Scale)	90 units on a scale Standard Deviation 5	77 units on a scale Standard Deviation 20

SECONDARY outcome

Timeframe: Measurements were taken after wearing the study prosthesis for four weeks

Population: The number of participants for analysis is equal to the number of participants who completed the study protocol.

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).

Outcome measures

Measure	PIN Suspension n=5 Participants A modified patellar tendon bearing socket with a pin lock suspension system (PIN)	VASS Suspension n=5 Participants A total surface bearing socket with a vacuum-assisted suspension system (VASS).
Ambulation (PEQ Scale)	95 units on a scale Standard Deviation 6	67 units on a scale Standard Deviation 22

SECONDARY outcome

Timeframe: Measurements were taken after wearing the study prosthesis for four weeks

Population: The number of participants for analysis is equal to the number of participants who completed the study protocol.

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).

Outcome measures

Measure	PIN Suspension n=5 Participants A modified patellar tendon bearing socket with a pin lock suspension system (PIN)	VASS Suspension n=5 Participants A total surface bearing socket with a vacuum-assisted suspension system (VASS).
Frustration (PEQ Scale)	91 units on a scale Standard Deviation 11	43 units on a scale Standard Deviation 29

Adverse Events

Entire Study Population

Serious events: 0 serious events

Other events: 1 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Measure	Entire Study Population n=17 participants at risk Includes participants randomized to receive PIN first and VASS first.
Injury, poisoning and procedural complications Prosthesis failure	5.9% 1/17 • Number of events 1

Additional Information

Glenn K. Klute, PhD

Dept. of Veterans Affairs, Rehabilitation Research & Development Service

Phone: 206-277-6724

Email: Glenn.Klute@va.gov

Results disclosure agreements

• Principal investigator is a sponsor employee
• Publication restrictions are in place