Amputation, Artificial Limbs
Conditions
Keywords
prosthesis, prosthetic socket, transfemoral amputation, socket comfort, gait biomechanics
Brief summary
The overall objective of this study is to provide a more comfortable and functional prosthetic socket for persons with transfemoral amputation that will ultimately improve their quality of life.
Detailed description
The proposed clinical trial will be an assessor-blinded prospective randomized cross-over trial wherein participants with unilateral transfemoral amputation will be randomized to using one of two socket conditions (i.e., sub-ischial or ischial containment) before crossing over to the other socket condition. Random allocation (computer-generated) utilizing blocks of random size will be used to assign the initial treatment condition. The trial will be balanced such that all subjects will receive all treatments (i.e., both socket conditions) and that all subjects will participate for the same number of periods (i.e., two). While a washout period is not strictly necessary, it is effectively included as subjects will need to transition back to their usual, pre-study socket/prosthesis while the second test socket is fabricated. Allocation of intervention will be concealed from the investigators until after a subject is enrolled. The starting socket design will be enclosed in sequentially numbered, opaque, sealed envelopes. Envelopes will be opened sequentially and only after the participant's name and other details are written on the appropriate envelope. Blinding of prosthetic interventions is challenging given that they are devices that must be custom-fabricated and donned each day by the subject. Hence, for this study only the assessor will be blinded. The blinded assessor will be responsible for administration of the clinical performance and patient-reported measures as well as processing of motion analysis data.
Interventions
DEVICENorthwestern University Flexible Sub-Ischial Vacuum Socket
NU-FlexSIV sockets have lower proximal trim lines, do not impinge on the pelvis, are highly flexible so as to allow better comfort during sitting and when muscles move within the socket during activity, and are held securely to the residual limb by suction from a vacuum pump and from compression exerted by the deliberately undersized liner and socket.
DEVICEIschial Containment Socket
Ischial Containment (IC) sockets are more rigid and have a narrower medio-lateral dimension than anterior-posterior dimension. The socket encapsulates the ischium, ischial ramus and greater trochanter, limiting hip range of motion and comfort.
Sponsors
United States Department of Defense
Jesse Brown VA Medical Center
Scheck and Siress
Northwestern University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
SINGLE (Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
21 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* unilateral transfemoral amputation * have used a prosthesis for two or more years * have a residual limb that is stable in volume and free from wounds * be physically fit enough to participate in the performance tests (Medicare Functional Classification Level K3 or K4) * have no previous experience of the sub-ischial socket * able to complete all visits for the duration of the protocol
Exclusion criteria
* have a residual limb femur of less than 5-inches * co-morbidities that affect function, including neurologic abnormalities (e.g. neuropathic pain that would interfere with the study) * do not speak and read English
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Socket Comfort Score (SCS) Between IC Socket and NU-FlexSIV Sockets at 7 Weeks. | 7 weeks | Socket comfort was assessed after each socket was worn for 7 weeks. SCS is an ordinal scale where the subject responds to the question, On a 0 to 10 scale, if 0 represents the most uncomfortable socket fit you can imagine, and 10 represents the most comfortable socket fit, how would you score the comfort of the socket of your artificial limb at the moment? |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Step Length Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 7 weeks | Step length was assessed after each socket was worn for 7 weeks. Participants walked along a 12 meter, level walkway at their normal self-selected speed. Marker based motion capture was used to assess step length (cm). |
| Hip Extension Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 7 weeks | Hip extension was assessed after each socket was worn for 7 weeks. Participants walked along a 12 meter, level walkway at their normal self-selected speed. Marker based motion capture was used to assess hip extension (degrees). |
| Hip Range of Motion Between the IC Socket and NU-FlexSIV Socket 7 Weeks. | 7 weeks | Hip range of motion was assessed after each socket was worn for 7 weeks. Participants walked along a 12 meter, level walkway at their normal self-selected speed. Marker based motion capture was used to assess hip range of motion (degrees). |
| Trunk Motion Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 7 weeks | Trunk motion was assessed after each socket was worn for 7 weeks. Participants walked along a 12 meter, level walkway at their normal self-selected speed. Marker based motion capture was used to assess trunk motion (degrees). |
| Orthotics and Prosthetics Users' Survey (OPUS) Lower-Extremity Functional Status Measure Between the IC Socket and NU-FlexSIV Socket at 7 Weeks | 7 weeks | Lower-Extremity Functional Status was assessed after each socket was worn for 7 weeks. The OPUS Lower-Extremity Functional Status measure is a self-report instrument that assesses functional status in persons who use orthoses and prostheses. It is comprised of 20 items rated on a 5-point rating scale. Responses to items are summed to produce a total score for the measure (0 to 80) with higher scores representing better functional status. |
| Walking Speed Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 7 weeks | Walking speed was assessed after each socket was worn for 7 weeks. Participants walked along a 12 meter, level walkway at their normal self-selected speed. Marker based motion capture was used to assess walking speed (m/s). |
| Orthotics and Prosthetics Users' Survey (OPUS) Satisfaction With Device Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 7 weeks | Satisfaction with Device was assessed after each socket was worn for 7 weeks. The OPUS Satisfaction with Device measure is a set of 11 items rated on a 5-point rating scale. Responses to items are summed to produce a total score. 9 items were used in this study for a possible score of 9 to 45 with higher scores representing better satisfaction. |
| 5-Times Rapid Sit-to-Stand Test (RSTS) Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 7 weeks | The 5-Times Rapid-Sit-to-Stand Test was assessed after each socket was worn for 7 weeks. Participants were asked to rise from a chair of standard height five times as fast as possible with their arms folded across their chests. Performance was timed. |
| Four-Square-Step Test (FSST) Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 7 weeks | The Four-Square-Step Test was assessed after each socket was worn for 7 weeks. Four sticks were placed flat on the floor in a cross that denoted a square. Participants were asked to complete a stepping sequence as fast as possible. Performance was timed. |
| T-Test of Agility (T-Test) Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 7 weeks | The T-Test was assessed after each socket was worn for 7 weeks. Four markers were set out so a T could be traced among them. The subject was asked to move as fast as possible between the markers, moving forwards, sideways and backwards. Performance was timed and reported in seconds. |
| Orthotics andProsthetics Users' Survey (OPUS) Health Related Quality of Life Index Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 7 weeks | Health Related Quality of life was assessed after each socket was worn for 7 weeks. The OPUS Health Related Quality of Life measure is self-report instrument comprised of 23 items that are evaluated with a 5-point rating scale. Responses to items are summed to produce a total score for the index (0 to 92) with higher scores representing better quality of life. |
Countries
United States
Participant flow
Recruitment details
Recruitment occurred between April 2016 and May 2019. Subjects were recruited and sockets fit and fabricated at local prosthetic clinical care facilities. Data were collected in an academic research lab.
Pre-assignment details
30 subjects were randomized.
Participants by arm
| Arm | Count |
|---|---|
| Ischial Containment Socket Then NU-FlexSIV Socket Participants wore the Ischial Containment Socket for 7 weeks then wore the NU-FlexSIV Socket for 7 weeks. | 15 |
| NU-FlexSIV Socket Then Ischial Containment Socket Participants wore the NU-FlexSIV Socket for 7 weeks then wore the Ischial Containment Socket for 7 weeks. | 15 |
| Total | 30 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| First Intervention (7 Weeks) | Adverse Event | 1 | 2 |
| First Intervention (7 Weeks) | Physician Decision | 1 | 0 |
| First Intervention (7 Weeks) | Withdrawal by Subject | 0 | 2 |
| Second Intervention (7 Weeks) | Adverse Event | 2 | 1 |
| Second Intervention (7 Weeks) | Physician Decision | 1 | 0 |
| Second Intervention (7 Weeks) | Withdrawal by Subject | 1 | 1 |
Baseline characteristics
| Characteristic | NU-FlexSIV Socket Then Ischial Containment Socket | Ischial Containment Socket Then NU-FlexSIV Socket | Total |
|---|---|---|---|
| Age, Continuous | 39.9 years STANDARD_DEVIATION 11.6 | 50.6 years STANDARD_DEVIATION 13.7 | 45.9 years STANDARD_DEVIATION 13.7 |
| Amputee Mobility Predictor with Prosthesis | 42.1 score: 0-47 STANDARD_DEVIATION 3.2 | 43.2 score: 0-47 STANDARD_DEVIATION 1.8 | 42.7 score: 0-47 STANDARD_DEVIATION 2.6 |
| Cause of Amputation Cancer | 3 Participants | 4 Participants | 7 Participants |
| Cause of Amputation Infection | 1 Participants | 0 Participants | 1 Participants |
| Cause of Amputation Trauma | 6 Participants | 9 Participants | 15 Participants |
| Cause of Amputation Unknown | 4 Participants | 1 Participants | 5 Participants |
| Cause of Amputation Vascular | 1 Participants | 1 Participants | 2 Participants |
| Ethnicity (NIH/OMB) Hispanic or Latino | 1 Participants | 2 Participants | 3 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 10 Participants | 12 Participants | 22 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 4 Participants | 1 Participants | 5 Participants |
| K-Level Classification K3 | 3 Participants | 4 Participants | 7 Participants |
| K-Level Classification K4 | 12 Participants | 11 Participants | 23 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Black or African American | 4 Participants | 4 Participants | 8 Participants |
| Race (NIH/OMB) More than one race | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 4 Participants | 1 Participants | 5 Participants |
| Race (NIH/OMB) White | 7 Participants | 10 Participants | 17 Participants |
| Sex: Female, Male Female | 6 Participants | 1 Participants | 7 Participants |
| Sex: Female, Male Male | 9 Participants | 14 Participants | 23 Participants |
| Time Since Amputation | 17.6 years STANDARD_DEVIATION 12.7 | 27.6 years STANDARD_DEVIATION 17.1 | 23.2 years STANDARD_DEVIATION 15.8 |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 25 | 0 / 25 |
| other Total, other adverse events | 14 / 25 | 18 / 25 |
| serious Total, serious adverse events | 0 / 25 | 0 / 25 |
Outcome results
Primary
Socket Comfort Score (SCS) Between IC Socket and NU-FlexSIV Sockets at 7 Weeks.
Socket comfort was assessed after each socket was worn for 7 weeks. SCS is an ordinal scale where the subject responds to the question, On a 0 to 10 scale, if 0 represents the most uncomfortable socket fit you can imagine, and 10 represents the most comfortable socket fit, how would you score the comfort of the socket of your artificial limb at the moment?
Time frame: 7 weeks
Population: Cross-sectional analysis was conducted with the 19 participants who completed the 7-week data collection visit for this outcome measure for each socket.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| NU-FlexSIV Socket | Socket Comfort Score (SCS) Between IC Socket and NU-FlexSIV Sockets at 7 Weeks. | 8.5 score on a scale | Standard Deviation 1.1 |
| Ischial Containment Socket | Socket Comfort Score (SCS) Between IC Socket and NU-FlexSIV Sockets at 7 Weeks. | 6.8 score on a scale | Standard Deviation 1.8 |
p-value: <0.00195% CI: [0.8, 2.3]t-test, 2 sided
Secondary
5-Times Rapid Sit-to-Stand Test (RSTS) Between the IC Socket and NU-FlexSIV Socket at 7 Weeks.
The 5-Times Rapid-Sit-to-Stand Test was assessed after each socket was worn for 7 weeks. Participants were asked to rise from a chair of standard height five times as fast as possible with their arms folded across their chests. Performance was timed.
Time frame: 7 weeks
Population: Cross-sectional analysis was conducted with the 19 participants who completed the 7-week data collection visit for this outcome measure for each socket.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| NU-FlexSIV Socket | 5-Times Rapid Sit-to-Stand Test (RSTS) Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 12.7 seconds | Standard Deviation 4.5 |
| Ischial Containment Socket | 5-Times Rapid Sit-to-Stand Test (RSTS) Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 14.8 seconds | Standard Deviation 8.8 |
p-value: 0.1895% CI: [-5.4, 1.1]t-test, 2 sided
Secondary
Four-Square-Step Test (FSST) Between the IC Socket and NU-FlexSIV Socket at 7 Weeks.
The Four-Square-Step Test was assessed after each socket was worn for 7 weeks. Four sticks were placed flat on the floor in a cross that denoted a square. Participants were asked to complete a stepping sequence as fast as possible. Performance was timed.
Time frame: 7 weeks
Population: Cross-sectional analysis was conducted with the 19 participants who completed the 7-week data collection visit for this outcome measure for each socket.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| NU-FlexSIV Socket | Four-Square-Step Test (FSST) Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 9.7 seconds | Standard Deviation 2 |
| Ischial Containment Socket | Four-Square-Step Test (FSST) Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 9.5 seconds | Standard Deviation 2.1 |
p-value: 0.4795% CI: [-0.4, 0.9]t-test, 2 sided
Secondary
Hip Extension Between the IC Socket and NU-FlexSIV Socket at 7 Weeks.
Hip extension was assessed after each socket was worn for 7 weeks. Participants walked along a 12 meter, level walkway at their normal self-selected speed. Marker based motion capture was used to assess hip extension (degrees).
Time frame: 7 weeks
Population: Cross-sectional analysis was conducted with the 19 participants who completed the 7-week data collection visit for this outcome measure for each socket.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| NU-FlexSIV Socket | Hip Extension Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | -3.30 degrees | Standard Deviation 8.65 |
| Ischial Containment Socket | Hip Extension Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | -3.10 degrees | Standard Deviation 8.67 |
p-value: 0.84795% CI: [-2, 2.42]t-test, 2 sided
Secondary
Hip Range of Motion Between the IC Socket and NU-FlexSIV Socket 7 Weeks.
Hip range of motion was assessed after each socket was worn for 7 weeks. Participants walked along a 12 meter, level walkway at their normal self-selected speed. Marker based motion capture was used to assess hip range of motion (degrees).
Time frame: 7 weeks
Population: Cross-sectional analysis was conducted with the 19 participants who completed the 7-week data collection visit for this outcome measure for each socket.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| NU-FlexSIV Socket | Hip Range of Motion Between the IC Socket and NU-FlexSIV Socket 7 Weeks. | 44.34 degrees | Standard Deviation 4.9 |
| Ischial Containment Socket | Hip Range of Motion Between the IC Socket and NU-FlexSIV Socket 7 Weeks. | 43.30 degrees | Standard Deviation 5.22 |
p-value: <0.01795% CI: [-2.42, 0.34]t-test, 2 sided
Secondary
Orthotics andProsthetics Users' Survey (OPUS) Health Related Quality of Life Index Between the IC Socket and NU-FlexSIV Socket at 7 Weeks.
Health Related Quality of life was assessed after each socket was worn for 7 weeks. The OPUS Health Related Quality of Life measure is self-report instrument comprised of 23 items that are evaluated with a 5-point rating scale. Responses to items are summed to produce a total score for the index (0 to 92) with higher scores representing better quality of life.
Time frame: 7 weeks
Population: Cross-sectional analysis was conducted with the 19 participants who completed the 7-week data collection visit for this outcome measure for each socket.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| NU-FlexSIV Socket | Orthotics andProsthetics Users' Survey (OPUS) Health Related Quality of Life Index Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 69.1 score on a scale | Standard Deviation 17.1 |
| Ischial Containment Socket | Orthotics andProsthetics Users' Survey (OPUS) Health Related Quality of Life Index Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 70.2 score on a scale | Standard Deviation 16.3 |
p-value: 0.6295% CI: [-6, 3.7]t-test, 2 sided
Secondary
Orthotics and Prosthetics Users' Survey (OPUS) Lower-Extremity Functional Status Measure Between the IC Socket and NU-FlexSIV Socket at 7 Weeks
Lower-Extremity Functional Status was assessed after each socket was worn for 7 weeks. The OPUS Lower-Extremity Functional Status measure is a self-report instrument that assesses functional status in persons who use orthoses and prostheses. It is comprised of 20 items rated on a 5-point rating scale. Responses to items are summed to produce a total score for the measure (0 to 80) with higher scores representing better functional status.
Time frame: 7 weeks
Population: Cross-sectional analysis was conducted with the 19 participants who completed the 7-week data collection visit for this outcome measure for each socket.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| NU-FlexSIV Socket | Orthotics and Prosthetics Users' Survey (OPUS) Lower-Extremity Functional Status Measure Between the IC Socket and NU-FlexSIV Socket at 7 Weeks | 58.3 score on a scale | Standard Deviation 10.4 |
| Ischial Containment Socket | Orthotics and Prosthetics Users' Survey (OPUS) Lower-Extremity Functional Status Measure Between the IC Socket and NU-FlexSIV Socket at 7 Weeks | 55.5 score on a scale | Standard Deviation 13.9 |
p-value: 0.295% CI: [-1.6, 7]t-test, 2 sided
Secondary
Orthotics and Prosthetics Users' Survey (OPUS) Satisfaction With Device Between the IC Socket and NU-FlexSIV Socket at 7 Weeks.
Satisfaction with Device was assessed after each socket was worn for 7 weeks. The OPUS Satisfaction with Device measure is a set of 11 items rated on a 5-point rating scale. Responses to items are summed to produce a total score. 9 items were used in this study for a possible score of 9 to 45 with higher scores representing better satisfaction.
Time frame: 7 weeks
Population: Cross-sectional analysis was conducted with the 19 participants who completed the 7-week data collection visit for this outcome measure for each socket.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| NU-FlexSIV Socket | Orthotics and Prosthetics Users' Survey (OPUS) Satisfaction With Device Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 35.1 score on a scale | Standard Deviation 6.5 |
| Ischial Containment Socket | Orthotics and Prosthetics Users' Survey (OPUS) Satisfaction With Device Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 32.5 score on a scale | Standard Deviation 7.3 |
p-value: 0.0795% CI: [-0.2, 5.3]t-test, 2 sided
Secondary
Step Length Between the IC Socket and NU-FlexSIV Socket at 7 Weeks.
Step length was assessed after each socket was worn for 7 weeks. Participants walked along a 12 meter, level walkway at their normal self-selected speed. Marker based motion capture was used to assess step length (cm).
Time frame: 7 weeks
Population: Cross-sectional analysis was conducted with the 19 participants who completed the 7-week data collection visit for this outcome measure for each socket.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| NU-FlexSIV Socket | Step Length Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 70.26 cm | Standard Deviation 10.2 |
| Ischial Containment Socket | Step Length Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 68.56 cm | Standard Deviation 9.63 |
p-value: 0.02695% CI: [-3.17, -0.23]t-test, 2 sided
Secondary
Trunk Motion Between the IC Socket and NU-FlexSIV Socket at 7 Weeks.
Trunk motion was assessed after each socket was worn for 7 weeks. Participants walked along a 12 meter, level walkway at their normal self-selected speed. Marker based motion capture was used to assess trunk motion (degrees).
Time frame: 7 weeks
Population: Cross-sectional analysis was conducted with the 19 participants who completed the 7-week data collection visit for this outcome measure for each socket.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| NU-FlexSIV Socket | Trunk Motion Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 3.61 degrees | Standard Deviation 3.23 |
| Ischial Containment Socket | Trunk Motion Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 3.73 degrees | Standard Deviation 3.7 |
p-value: 0.795% CI: [-0.53, 0.77]t-test, 2 sided
Secondary
T-Test of Agility (T-Test) Between the IC Socket and NU-FlexSIV Socket at 7 Weeks.
The T-Test was assessed after each socket was worn for 7 weeks. Four markers were set out so a T could be traced among them. The subject was asked to move as fast as possible between the markers, moving forwards, sideways and backwards. Performance was timed and reported in seconds.
Time frame: 7 weeks
Population: Cross-sectional analysis was conducted with the 19 participants who completed the 7-week data collection visit for this outcome measure for each socket.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| NU-FlexSIV Socket | T-Test of Agility (T-Test) Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 41.8 seconds | Standard Error 13.3 |
| Ischial Containment Socket | T-Test of Agility (T-Test) Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 41.4 seconds | Standard Error 12.4 |
p-value: 0.6895% CI: [-1.4, 2]t-test, 2 sided
Secondary
Walking Speed Between the IC Socket and NU-FlexSIV Socket at 7 Weeks.
Walking speed was assessed after each socket was worn for 7 weeks. Participants walked along a 12 meter, level walkway at their normal self-selected speed. Marker based motion capture was used to assess walking speed (m/s).
Time frame: 7 weeks
Population: Cross-sectional analysis was conducted with the 19 participants who completed the 7-week data collection visit for this outcome measure for each socket.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| NU-FlexSIV Socket | Walking Speed Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 1.14 m/s | Standard Deviation 0.2 |
| Ischial Containment Socket | Walking Speed Between the IC Socket and NU-FlexSIV Socket at 7 Weeks. | 1.13 m/s | Standard Deviation 0.17 |
p-value: 0.66495% CI: [-0.06, 0.04]t-test, 2 sided