Trial Outcomes & Findings for Transfemoral Socket Design and Muscle Function (NCT NCT04212299)

NCT ID: NCT04212299

Last Updated: 2024-10-10

Results Overview

Hip flexor, extensor, adductor and abductor muscle strength will be measured in transfemoral prosthesis users using a motor-driven isokinetic dynamometer. Muscular strength will be assessed via average peak torque (i.e., highest torque) across the first three repetitions of 12.

• Recruitment status: COMPLETED
• Study phase: NA
• Target enrollment: 5 participants
• Primary outcome timeframe: Baseline
• Results posted on: 2024-10-10

Participant Flow

Participant milestones

Measure	Baseline Ischial Containment to Subischial Socket Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).
Baseline in Ischial Containment Socket STARTED	5
Baseline in Ischial Containment Socket COMPLETED	5
Baseline in Ischial Containment Socket NOT COMPLETED	0
8-week Follow up in Sub-ischial Socket STARTED	5
8-week Follow up in Sub-ischial Socket COMPLETED	5
8-week Follow up in Sub-ischial Socket NOT COMPLETED	0
42-week Follow up in Sub-ischial Socket STARTED	5
42-week Follow up in Sub-ischial Socket COMPLETED	4
42-week Follow up in Sub-ischial Socket NOT COMPLETED	1

Reasons for withdrawal

Measure

Baseline Ischial Containment to Subischial Socket Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

42-week Follow up in Sub-ischial Socket Participant experienced a heart attack

1

Baseline Characteristics

Transfemoral Socket Design and Muscle Function

Baseline characteristics by cohort

Measure	Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).
Age, Continuous	45.6 years STANDARD_DEVIATION 21.4 • n=5 Participants
Sex: Female, Male Female	2 Participants n=5 Participants
Sex: Female, Male Male	3 Participants n=5 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	1 Participants n=5 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	4 Participants n=5 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants
Race (NIH/OMB) Asian	0 Participants n=5 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants
Race (NIH/OMB) Black or African American	3 Participants n=5 Participants
Race (NIH/OMB) White	2 Participants n=5 Participants
Race (NIH/OMB) More than one race	0 Participants n=5 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants
Region of Enrollment United States	5 participants n=5 Participants
Body mass	78.8 kg STANDARD_DEVIATION 6.81 • n=5 Participants
Height	1.73 meters STANDARD_DEVIATION 0.06 • n=5 Participants
Residual limb length	26 cm STANDARD_DEVIATION 3.2 • n=5 Participants
Time since amputation	8 years STANDARD_DEVIATION 7.5 • n=5 Participants
Cause of amputation Traumatic	3 Participants n=5 Participants
Cause of amputation Dysvascular	2 Participants n=5 Participants
Medicare Functional Classification Level (K-Level) MFCL 1	0 Participants n=5 Participants
Medicare Functional Classification Level (K-Level) MFCL 2	1 Participants n=5 Participants
Medicare Functional Classification Level (K-Level) MFCL 3	4 Participants n=5 Participants
Medicare Functional Classification Level (K-Level) MFCL 4	0 Participants n=5 Participants
Number of falls in past 12 months	2 falls STANDARD_DEVIATION 0.22 • n=5 Participants
Activities-specific Balance Confidence Scale score	2.33 units on a scale 0 to 4 STANDARD_DEVIATION 0.32 • n=5 Participants
Prosthesis Limb Users Survey of Mobility	47.9 units on a scale STANDARD_DEVIATION 1.81 • n=5 Participants

PRIMARY outcome

Timeframe: Baseline

Hip flexor, extensor, adductor and abductor muscle strength will be measured in transfemoral prosthesis users using a motor-driven isokinetic dynamometer. Muscular strength will be assessed via average peak torque (i.e., highest torque) across the first three repetitions of 12.

Outcome measures

Measure	Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).
Residual Limb Hip Muscle Peak Torque at Baseline Hip flexion	14.9 newton-meters / kg*meters Interval 7.29 to 22.6
Residual Limb Hip Muscle Peak Torque at Baseline Hip extension	25.6 newton-meters / kg*meters Interval 18.9 to 32.4
Residual Limb Hip Muscle Peak Torque at Baseline Hip abduction	25.6 newton-meters / kg*meters Interval 19.0 to 32.4
Residual Limb Hip Muscle Peak Torque at Baseline Hip adduction	13.1 newton-meters / kg*meters Interval 8.63 to 17.5

PRIMARY outcome

Timeframe: 8 weeks after intervention

Hip flexor, extensor, adductor and abductor muscle strength will be measured in transfemoral prosthesis users using a motor-driven isokinetic dynamometer. Muscular strength will be assessed via average peak torque (i.e., highest torque) across the first three repetitions of 12. Comparison will be made to baseline measure.

Outcome measures

Measure	Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).
Residual Limb Hip Muscle Peak Torque at 8-weeks Hip extension	23.6 newton-meters / kg*meters Interval 15.2 to 31.9
Residual Limb Hip Muscle Peak Torque at 8-weeks Hip flexion	14.1 newton-meters / kg*meters Interval 8.35 to 19.9
Residual Limb Hip Muscle Peak Torque at 8-weeks Hip abduction	22.4 newton-meters / kg*meters Interval 15.4 to 29.5
Residual Limb Hip Muscle Peak Torque at 8-weeks Hip adduction	13.3 newton-meters / kg*meters Interval 7.55 to 19.1

PRIMARY outcome

Timeframe: 42 weeks after intervention

Hip flexor, extensor, adductor and abductor muscle strength will be measured in transfemoral prosthesis users using a motor-driven isokinetic dynamometer. Muscular strength will be assessed via average peak torque (i.e., highest torque) across the first three repetitions of 12. Comparison will be made to baseline measure.

Outcome measures

Measure	Baseline Ischial Containment to Subischial Socket n=4 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).
Residual Limb Hip Muscle Peak Torque at 42-weeks Hip extension	19.1 newton-meters / kg*meters Interval 9.12 to 29.1
Residual Limb Hip Muscle Peak Torque at 42-weeks Hip flexion	12.2 newton-meters / kg*meters Interval 3.11 to 21.2
Residual Limb Hip Muscle Peak Torque at 42-weeks Hip abduction	21.6 newton-meters / kg*meters Interval 8.77 to 34.4
Residual Limb Hip Muscle Peak Torque at 42-weeks Hip adduction	10.1 newton-meters / kg*meters Interval 5.77 to 14.5

PRIMARY outcome

Timeframe: Baseline

Hip flexor, extensor, adductor and abductor muscle endurance will be measured in transfemoral prosthesis users using a motor-driven isokinetic dynamometer. Muscular endurance will be assessed via a fatigue index, calculated as a percentage of the difference between total work performed during the first and last 3 repetitions divided by total work over the first 3 repetitions. A higher fatigue index will be taken as evidence of reduced muscular endurance.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

Residual Limb Hip Muscle Endurance at Baseline

NA newton-meters / kg*meters Data were collected but could not be analyzed or summarized because most of the participants held back effort (i.e., self-paced) preventing an assessment of muscle endurance (i.e., change in peak torque from the first to the last trial). From this pilot protocol we have learned that in the future we need to use a single 30 second trial and look at changes from the first 3 seconds to the last 3 seconds for assessing hip muscle endurance in transfemoral prosthesis users.

PRIMARY outcome

Timeframe: 8 weeks after intervention

Hip flexor, extensor, adductor and abductor muscle endurance will be measured in transfemoral prosthesis users using a motor-driven isokinetic dynamometer. Muscular endurance will be assessed via a fatigue index, calculated as a percentage of the difference between total work performed during the first and last 3 repetitions divided by total work over the first 3 repetitions. A higher fatigue index will be taken as evidence of reduced muscular endurance. Comparison will be made to baseline measure.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

Residual Limb Hip Muscle Endurance at 8-weeks

NA newton-meters / kg*meters Data were collected but could not be analyzed or summarized because most of the participants held back effort (i.e., self-paced) preventing an assessment of muscle endurance (i.e., change in peak torque from the first to the last trial). From this pilot protocol we have learned that in the future we need to use a single 30 second trial and look at changes from the first 3 seconds to the last 3 seconds for assessing hip muscle endurance in transfemoral prosthesis users.

PRIMARY outcome

Timeframe: 42 weeks after intervention

Hip flexor, extensor, adductor and abductor muscle endurance will be measured in transfemoral prosthesis users using a motor-driven isokinetic dynamometer. Muscular endurance will be assessed via a fatigue index, calculated as a percentage of the difference between total work performed during the first and last 3 repetitions divided by total work over the first 3 repetitions. A higher fatigue index will be taken as evidence of reduced muscular endurance. Comparison will be made to baseline measure.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=4 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

Residual Limb Hip Muscle Endurance at 42-weeks

NA newton-meters / kg*meters Data were collected but could not be analyzed or summarized because most of the participants held back effort (i.e., self-paced) preventing an assessment of muscle endurance (i.e., change in peak torque from the first to the last trial). From this pilot protocol we have learned that in the future we need to use a single 30 second trial and look at changes from the first 3 seconds to the last 3 seconds for assessing hip muscle endurance in transfemoral prosthesis users.

PRIMARY outcome

Timeframe: Baseline

Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The duration of time each hip muscle was active during a stride was calculated as the percentage of the gait cycle (i.e., heel-strike to heel-strike) for which that EMG signal was above a baseline value (min: 0%, max: 100%). The larger the percentage of the gait cycle that a muscle was deemed to be active, the greater its duration.

Outcome measures

Measure	Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).
Residual Limb Hip Muscle Duration at Baseline Gluteus medius	76.5 percentage Interval 51.9 to 100.0
Residual Limb Hip Muscle Duration at Baseline Tensor fascia latae	78.7 percentage Interval 62.2 to 95.2
Residual Limb Hip Muscle Duration at Baseline Gluteus Maximus	71.9 percentage Interval 52.1 to 91.6
Residual Limb Hip Muscle Duration at Baseline Hamstrings	73.2 percentage Interval 42.0 to 100.0
Residual Limb Hip Muscle Duration at Baseline Rectus femoris	81.3 percentage Interval 52.9 to 100.0
Residual Limb Hip Muscle Duration at Baseline Adductor Magnus	72.3 percentage Interval 52.3 to 92.4

PRIMARY outcome

Timeframe: 8 weeks after intervention

Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The duration of time each hip muscle was active during a stride was calculated as the percentage of the gait cycle (i.e., heel-strike to heel-strike) for which that EMG signal was above a baseline value (min: 0%, max: 100%). The larger the percentage of the gait cycle that a muscle was deemed to be active, the greater its duration.

Outcome measures

Measure	Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).
Residual Limb Hip Muscle Duration at 8-weeks Tensor fascia latae	54.0 percentage Interval 33.0 to 75.0
Residual Limb Hip Muscle Duration at 8-weeks Rectus femoris	75.5 percentage Interval 49.7 to 100.0
Residual Limb Hip Muscle Duration at 8-weeks Adductor magnus	68.6 percentage Interval 32.1 to 100.0
Residual Limb Hip Muscle Duration at 8-weeks Gluteus maximus	64.0 percentage Interval 43.4 to 84.6
Residual Limb Hip Muscle Duration at 8-weeks Hamstrings	60.7 percentage Interval 26.6 to 94.8
Residual Limb Hip Muscle Duration at 8-weeks Gluteus medius	62.1 percentage Interval 22.5 to 100.0

PRIMARY outcome

Timeframe: 42 weeks

Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The duration of time each hip muscle was active during a stride was calculated as the percentage of the gait cycle (i.e., heel-strike to heel-strike) for which that EMG signal was above a baseline value (min: 0%, max: 100%). The larger the percentage of the gait cycle that a muscle was deemed to be active, the greater its duration.

Outcome measures

Measure	Baseline Ischial Containment to Subischial Socket n=4 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).
Residual Limb Hip Muscle Duration at at 42-weeks Gluteus maximus	60.1 percentage Interval 29.8 to 90.3
Residual Limb Hip Muscle Duration at at 42-weeks Gluteus medius	51.3 percentage Interval 7.96 to 94.6
Residual Limb Hip Muscle Duration at at 42-weeks Tensor fascia latae	45.1 percentage Interval 30.1 to 60.1
Residual Limb Hip Muscle Duration at at 42-weeks Rectus femoris	75.9 percentage Interval 45.5 to 100.0
Residual Limb Hip Muscle Duration at at 42-weeks Adductor magnus	53.0 percentage Interval 11.3 to 94.6
Residual Limb Hip Muscle Duration at at 42-weeks Hamstrings	61.1 percentage Interval 16.4 to 100.0

PRIMARY outcome

Timeframe: Baseline

Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The total amount of hip muscle activity was calculated as the integrated area under the EMG signal during a gait cycle (i.e., heel-strike to heel-strike). Each EMG signal was normalized (i.e., divided by its maximum value across all the gait cycles and multiple by 100. The integrated areas is therefore reported as a percentage of that maximum (min: 0%, max: 100%). The larger the integrated area the more the muscle was deemed to be active.

Outcome measures

Measure	Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).
Residual Limb Hip Muscle Integrated Area at Baseline Gluteus maximus	23.4 percentage of maximum value Interval 19.0 to 27.8
Residual Limb Hip Muscle Integrated Area at Baseline Hamstrings	23.6 percentage of maximum value Interval 8.71 to 38.5
Residual Limb Hip Muscle Integrated Area at Baseline Gluteus medius	24.3 percentage of maximum value Interval 12.5 to 36.2
Residual Limb Hip Muscle Integrated Area at Baseline Tensor fascia latae	24.0 percentage of maximum value Interval 17.9 to 29.9
Residual Limb Hip Muscle Integrated Area at Baseline Rectus femoris	27.4 percentage of maximum value Interval 16.3 to 38.6
Residual Limb Hip Muscle Integrated Area at Baseline Adductor magnus	20.5 percentage of maximum value Interval 13.7 to 27.4

PRIMARY outcome

Timeframe: 8 weeks after intervention

Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The total amount of hip muscle activity was calculated as the integrated area under the EMG signal during a gait cycle (i.e., heel-strike to heel-strike). Each EMG signal was normalized (i.e., divided by its maximum value across all the gait cycles and multiple by 100. The integrated areas is therefore reported as a percentage of that maximum (min: 0%, max: 100%). The larger the integrated area the more the muscle was deemed to be active.

Outcome measures

Measure	Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).
Residual Limb Hip Muscle Integrated Area at 8-weeks Gluteus maximus	15.3 percentage of maximum Interval 3.53 to 27.1
Residual Limb Hip Muscle Integrated Area at 8-weeks Hamstrings	14.4 percentage of maximum Interval 1.88 to 27.0
Residual Limb Hip Muscle Integrated Area at 8-weeks Gluteus medius	28.0 percentage of maximum Interval 1.18 to 64.2
Residual Limb Hip Muscle Integrated Area at 8-weeks Tensor fascia latae	13.4 percentage of maximum Interval 1.39 to 25.5
Residual Limb Hip Muscle Integrated Area at 8-weeks Rectus femoris	24.2 percentage of maximum Interval 8.42 to 39.9
Residual Limb Hip Muscle Integrated Area at 8-weeks Adductor magnus	22.7 percentage of maximum Interval 2.28 to 45.8

PRIMARY outcome

Timeframe: 42 weeks after intervention

Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The total amount of hip muscle activity was calculated as the integrated area under the EMG signal during a gait cycle (i.e., heel-strike to heel-strike). Each EMG signal was normalized (i.e., divided by its maximum value across all the gait cycles and multiple by 100. The integrated areas is therefore reported as a percentage of that maximum (min: 0%, max: 100%). The larger the integrated area the more the muscle was deemed to be active.

Outcome measures

Measure	Baseline Ischial Containment to Subischial Socket n=4 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).
Residual Limb Hip Muscle Integrated Area at 42-weeks Tensor fascia latae	7.66 percentage of maximum Interval 2.94 to 12.38
Residual Limb Hip Muscle Integrated Area at 42-weeks Gluteus maximus	30.9 percentage of maximum Interval 1.82 to 76.6
Residual Limb Hip Muscle Integrated Area at 42-weeks Hamstrings	21.7 percentage of maximum Interval 1.99 to 46.5
Residual Limb Hip Muscle Integrated Area at 42-weeks Gluteus medius	17.3 percentage of maximum Interval 1.1 to 40.6
Residual Limb Hip Muscle Integrated Area at 42-weeks Rectus femoris	25.1 percentage of maximum Interval 5.69 to 44.6
Residual Limb Hip Muscle Integrated Area at 42-weeks Adductor magnus	15.2 percentage of maximum Interval 2.37 to 39.7

PRIMARY outcome

Timeframe: Baseline

Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The highest level of hip muscle activity was calculated as the peak of the EMG signal during a gait cycle (i.e., heel-strike to heel-strike). Each EMG signal was normalized (i.e., divided by its maximum value across all the gait cycles recorded during baseline). The peak EMG is therefore typically reported as a value between 0 and 1. However, if the peak value during assessments increases relative to baseline, the value of the peak activity will exceed 1. The larger the peak value the greater the activation of that muscle.

Outcome measures

Measure	Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).
Peak Residual Limb Hip Muscle Activity at Baseline Gluteus maximus	1.00 mV Peak muscle activity is amplitude normalized to its maximum value at baseline. Consequently all participants have a value of 1.0, creating no dispersion.
Peak Residual Limb Hip Muscle Activity at Baseline Hamstrings	1.00 mV Peak muscle activity is amplitude normalized to its maximum value at baseline. Consequently all participants have a value of 1.0, creating no dispersion.
Peak Residual Limb Hip Muscle Activity at Baseline Gluteus medius	1.00 mV Peak muscle activity is amplitude normalized to its maximum value at baseline. Consequently all participants have a value of 1.0, creating no dispersion.
Peak Residual Limb Hip Muscle Activity at Baseline Tensor fascia latae	1.00 mV Peak muscle activity is amplitude normalized to its maximum value at baseline. Consequently all participants have a value of 1.0, creating no dispersion.
Peak Residual Limb Hip Muscle Activity at Baseline Rectus femoris	1.00 mV Peak muscle activity is amplitude normalized to its maximum value at baseline. Consequently all participants have a value of 1.0, creating no dispersion.
Peak Residual Limb Hip Muscle Activity at Baseline Adductor magnus	1.00 mV Peak muscle activity is amplitude normalized to its maximum value at baseline. Consequently all participants have a value of 1.0, creating no dispersion.

PRIMARY outcome

Timeframe: 8 weeks after intervention

Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The highest level of hip muscle activity was calculated as the peak of the EMG signal during a gait cycle (i.e., heel-strike to heel-strike). Each EMG signal was normalized (i.e., divided by its maximum value across all the gait cycles recorded during baseline). The peak EMG is therefore typically reported as a value between 0 and 1. However, if the peak value during assessments increases relative to baseline, the value of the peak activity will exceed 1. The larger the peak value the greater the activation of that muscle.

Outcome measures

Measure	Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).
Peak Residual Limb Hip Muscle Activity at 8 Weeks Gluteus maximus	0.51 mV Interval 0.23 to 0.78
Peak Residual Limb Hip Muscle Activity at 8 Weeks Hamstrings	0.71 mV Interval 0.37 to 1.04
Peak Residual Limb Hip Muscle Activity at 8 Weeks Gluteus medius	1.46 mV Interval 0.38 to 3.3
Peak Residual Limb Hip Muscle Activity at 8 Weeks Adductor magnus	0.90 mV Interval 0.42 to 1.37
Peak Residual Limb Hip Muscle Activity at 8 Weeks Tensor fascia latae	0.71 mV Interval 0.37 to 1.05
Peak Residual Limb Hip Muscle Activity at 8 Weeks Rectus femoris	0.82 mV Interval 0.5 to 1.14

PRIMARY outcome

Timeframe: 42 weeks after intervention

Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The highest level of hip muscle activity was calculated as the peak of the EMG signal during a gait cycle (i.e., heel-strike to heel-strike). Each EMG signal was normalized (i.e., divided by its maximum value across all the gait cycles recorded during baseline). The peak EMG is therefore typically reported as a value between 0 and 1. However, if the peak value during assessments increases relative to baseline, the value of the peak activity will exceed 1. The larger the peak value the greater the activation of that muscle.

Outcome measures

Measure	Baseline Ischial Containment to Subischial Socket n=4 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).
Peak Residual Limb Hip Muscle Activity at 42 Weeks Tensor fascia latae	0.47 mV Interval 0.12 to 0.82
Peak Residual Limb Hip Muscle Activity at 42 Weeks Gluteus maximus	1.33 mV Interval 0.09 to 2.57
Peak Residual Limb Hip Muscle Activity at 42 Weeks Hamstrings	0.85 mV Interval 0.29 to 1.41
Peak Residual Limb Hip Muscle Activity at 42 Weeks Gluteus medius	1.29 mV Interval 0.42 to 3.0
Peak Residual Limb Hip Muscle Activity at 42 Weeks Rectus femoris	1.18 mV Interval 0.5 to 1.86
Peak Residual Limb Hip Muscle Activity at 42 Weeks Adductor magnus	0.65 mV Interval 0.12 to 1.17

SECONDARY outcome

Timeframe: Baseline

A test of dynamic balance and coordination that assesses the participant's ability to step over objects forward, sideways, and backwards. Test was administered and scored as the best time (i.e., fastest) of two trials.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

Four Square Step Test at Baseline

17.91 seconds Interval 6.63 to 29.2

SECONDARY outcome

Timeframe: 8-weeks after intervention

A test of dynamic balance and coordination that assesses the participant's ability to step over objects forward, sideways, and backwards. Test was administered and scored as the best time (i.e., fastest) of two trials.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

Four Square Step Test at 8 Weeks

15.1 seconds Interval 5.45 to 24.8

SECONDARY outcome

Timeframe: 42-weeks after intervention

A test of dynamic balance and coordination that assesses the participant's ability to step over objects forward, sideways, and backwards. Test was administered and scored as the best time (i.e., fastest) of two trials.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=4 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

Four Square Step Test at 42 Weeks

11.4 seconds Interval 7.13 to 15.7

SECONDARY outcome

Timeframe: Baseline

A test of static balance that assesses the participant's ability to remain upright on one leg. Test was administered and scored as the best time (i.e., longest) of two trials. Longer times imply better static balance.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

One Leg Stance Test at Baseline

NA seconds Transfemoral prosthesis users were unable to stand on one leg at all, therefore the test was not performed.

SECONDARY outcome

Timeframe: 8 weeks after intervention

A test of static balance that assesses the participant's ability to remain upright on one leg. Test was administered and scored as the best time (i.e., longest) of two trials. Longer times imply better static balance.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

One Leg Stance Test at 8 Weeks

NA seconds Transfemoral prosthesis users were unable to stand on one leg at all, therefore the test was not performed.

SECONDARY outcome

Timeframe: 42 weeks after intervention

A test of static balance that assesses the participant's ability to remain upright on one leg. Test was administered and scored as the best time (i.e., longest) of two trials. Longer times imply better static balance.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=4 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

One Leg Stance Test at 42 Weeks

NA seconds Transfemoral prosthesis users were unable to stand on one leg at all, therefore the test was not performed.

SECONDARY outcome

Timeframe: Baseline

The 10MWT assesses walking speed in meters per second over a short duration. A faster speed is consider better walking performance. The fastest of 2 trials was used.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

10-Meter Walk Test at Baseline

0.91 meters/second Interval 0.57 to 1.24

SECONDARY outcome

Timeframe: 8 weeks after intervention

The 10MWT assesses walking speed in meters per second over a short duration. A faster speed is consider better walking performance. The fastest of 2 trials was used.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

10-Meter Walk Test at 8 Weeks

1.09 meters/second Interval 0.78 to 1.4

SECONDARY outcome

Timeframe: 42 weeks after intervention

The 10MWT assesses walking speed in meters per second over a short duration. A faster speed is consider better walking performance. The fastest of 2 trials was used.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=4 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

10-Meter Walk Test at 42 Weeks

1.13 meters/second Interval 0.89 to 1.36

SECONDARY outcome

Timeframe: Baseline

The 2-Minute Walk Test is a measurement of waking endurance that assesses walking distance over two minutes. A longer distance walked indicates greater walking endurance.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

2-Minute Walk Test at Baseline

119 meters Interval 71.1 to 167.0

SECONDARY outcome

Timeframe: 8-weeks after intervention.

The 2-Minute Walk Test is a measurement of waking endurance that assesses walking distance over two minutes. A longer distance walked indicates greater walking endurance.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

2-Minute Walk Test at 8 Weeks

122 meters Interval 61.6 to 182.0

SECONDARY outcome

Timeframe: 42-weeks after intervention.

The 2-Minute Walk Test is a measurement of waking endurance that assesses walking distance over two minutes. A longer distance walked indicates greater walking endurance.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=4 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

2-Minute Walk Test at 42 Weeks

138 meters Interval 93.3 to 182.0

SECONDARY outcome

Timeframe: 2 weeks prior to intervention (baseline)

To assess the volume of physical activity, transfemoral prosthesis users wore a StepWatch4 activity monitor (Modus Health, Edmonds, WA) for a 2-week period. Activity bouts, or periods of time in which steps occur in successive 10-second intervals, will be derived from the step count data. The volume of physical activity will be quantified by the mean number of steps per activity bout. Higher values will be taken as evidence of greater physical activity.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

Volume of Physical Activity at Baseline

27 mean number of steps per activity bout Interval 19.0 to 35.0

SECONDARY outcome

Timeframe: 8-weeks after intervention

To assess the volume of physical activity, transfemoral prosthesis users wore a StepWatch4 activity monitor (Modus Health, Edmonds, WA) for a 2-week period. Activity bouts, or periods of time in which steps occur in successive 10-second intervals, will be derived from the step count data. The volume of physical activity will be quantified by the mean number of steps per activity bout. Higher values will be taken as evidence of greater physical activity.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

Volume of Physical Activity at 8 Weeks

30 mean number of steps per activity bout Interval 20.0 to 40.0

SECONDARY outcome

Timeframe: 42-weeks after intervention

To assess the volume of physical activity, transfemoral prosthesis users wore a StepWatch4 activity monitor (Modus Health, Edmonds, WA) for a 2-week period. Activity bouts, or periods of time in which steps occur in successive 10-second intervals, will be derived from the step count data. The volume of physical activity will be quantified by the mean number of steps per activity bout. Higher values will be taken as evidence of greater physical activity.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=4 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

Volume of Physical Activity at 42 Weeks

34 mean number of steps per activity bout Interval 19.0 to 48.0

SECONDARY outcome

Timeframe: 2 weeks prior to intervention (baseline)

To assess the frequency of physical activity, transfemoral prosthesis users will wear a StepWatch4 activity monitor (Modus Health, Edmonds, WA) for a 2-week period. Activity bouts, or periods of time in which steps occur in successive 10-second intervals, will be derived from step count data. The frequency of physical activity will be quantified by the mean number of activity bouts per day. Higher values will be taken as evidence of greater physical activity.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

Frequency of Physical Activity at Baseline

63 mean number of activity bouts per day Interval 48.0 to 78.0

SECONDARY outcome

Timeframe: 8 weeks after intervention

To assess the frequency of physical activity, transfemoral prosthesis users will wear a StepWatch4 activity monitor (Modus Health, Edmonds, WA) for a 2-week period. Activity bouts, or periods of time in which steps occur in successive 10-second intervals, will be derived from step count data. The frequency of physical activity will be quantified by the mean number of activity bouts per day. Higher values will be taken as evidence of greater physical activity.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

Frequency of Physical Activity at 8 Weeks

74 mean number of activity bouts per day Interval 62.0 to 86.0

SECONDARY outcome

Timeframe: 42 weeks after intervention

To assess the frequency of physical activity, transfemoral prosthesis users will wear a StepWatch4 activity monitor (Modus Health, Edmonds, WA) for a 2-week period. Activity bouts, or periods of time in which steps occur in successive 10-second intervals, will be derived from step count data. The frequency of physical activity will be quantified by the mean number of activity bouts per day. Higher values will be taken as evidence of greater physical activity.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=4 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

Frequency of Physical Activity at 42 Weeks

81 mean number of activity bouts per day Interval 68.0 to 93.0

SECONDARY outcome

Timeframe: 2 weeks prior to intervention (baseline)

To assess the duration of physical activity, transfemoral prosthesis users will wear a StepWatch4 activity monitor (Modus Health, Edmonds, WA) for a 2-week period. Activity bouts, or periods of time in which steps occur in successive 10-second intervals, will be derived from step count data. The duration of physical activity will be quantified by the mean time (in minutes) of activity bouts per day. Higher values will be taken as evidence of greater physical activity.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

Duration of Physical Activity at Baseline

3.27 mean time (in minutes) of activity bouts Interval 2.87 to 3.67

SECONDARY outcome

Timeframe: 8 weeks after intervention

To assess the duration of physical activity, transfemoral prosthesis users will wear a StepWatch4 activity monitor (Modus Health, Edmonds, WA) for a 2-week period. Activity bouts, or periods of time in which steps occur in successive 10-second intervals, will be derived from step count data. The duration of physical activity will be quantified by the mean time (in minutes) of activity bouts per day. Higher values will be taken as evidence of greater physical activity.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=5 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

Duration of Physical Activity at 8 Weeks

3.68 mean time (in minutes) of activity bouts Interval 2.84 to 4.53

SECONDARY outcome

Timeframe: 42 weeks after intervention

To assess the duration of physical activity, transfemoral prosthesis users will wear a StepWatch4 activity monitor (Modus Health, Edmonds, WA) for a 2-week period. Activity bouts, or periods of time in which steps occur in successive 10-second intervals, will be derived from step count data. The duration of physical activity will be quantified by the mean time (in minutes) of activity bouts per day. Higher values will be taken as evidence of greater physical activity.

Outcome measures

Measure

Baseline Ischial Containment to Subischial Socket n=4 Participants Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS): The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).

Duration of Physical Activity at 42 Weeks

3.76 mean time (in minutes) of activity bouts Interval 2.71 to 4.81

Adverse Events

Baseline Ischial Containment to Subischial Socket

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Andrew Sawers

University of Illinois Chicago

Phone: 312-996-1427

Email: asawers@uic.edu

Results disclosure agreements

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