Trial Outcomes & Findings for Treatment of Post-Operative Pain Following Orthopedic Surgery With SPRINT® Peripheral Nerve Stimulation (PNS) System (NCT NCT04341948)

NCT ID: NCT04341948

Last Updated: 2025-08-27

Results Overview

All participants were asked to complete daily diaries to record their average knee pain during the past 24 hours on each day of a 7-day period using an 11-point numerical rating scale where 0 represents "No Pain" and 10 represents "Pain as bad as you can imagine." The average pain scores were calculated across the 7-day diary(s) at baseline and across weeks 5 to 8 post-start of treatment. Percent reduction was then calculated for each participant. To be considered a success, participants must have experienced ≥ 50% reduction in average knee pain. The number of successes is presented.

Recruitment status

COMPLETED

Study phase

Target enrollment

56 participants

Primary outcome timeframe

Baseline and 5 to 8 weeks post-Start of Treatment (SOT)

Results posted on

2025-08-27

Participant Flow

After obtaining informed consent, participants were evaluated for eligibility.

Participant milestones

Participant milestones
Measure	Group 1 (Treatment) Participants in Group 1 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received electrical stimulation for up to 8 weeks with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 (Control) Participants in Group 2 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received up to 8 weeks of sham stimulation. Three months after start of sham treatment, participants were given the option to crossover and receive electrical stimulation treatment with the SPRINT Peripheral Nerve Stimulation (PNS) System.
Overall Study STARTED	29	27
Overall Study Randomized	29	27
Overall Study Safety Analysis Set	28	27
Overall Study Full Analysis Set	20	21
Overall Study Per Protocol Set	16	19
Overall Study Group 2 Crossover Safety Set	0	11
Overall Study COMPLETED	15	20
Overall Study NOT COMPLETED	14	7

Reasons for withdrawal

Reasons for withdrawal
Measure	Group 1 (Treatment) Participants in Group 1 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received electrical stimulation for up to 8 weeks with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 (Control) Participants in Group 2 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received up to 8 weeks of sham stimulation. Three months after start of sham treatment, participants were given the option to crossover and receive electrical stimulation treatment with the SPRINT Peripheral Nerve Stimulation (PNS) System.
Overall Study Adverse Event	0	1
Overall Study Lost to Follow-up	6	1
Overall Study Physician Decision	1	2
Overall Study Withdrawal by Participant	6	3
Overall Study Lack of compliance by Participant	1	0

Baseline Characteristics

Treatment of Post-Operative Pain Following Orthopedic Surgery With SPRINT® Peripheral Nerve Stimulation (PNS) System

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Group 1 (Treatment) n=29 Participants Participants in Group 1 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received electrical stimulation for up to 8 weeks with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 (Control) n=27 Participants Participants in Group 2 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received up to 8 weeks of sham stimulation. Three months after start of sham treatment, participants were given the option to crossover and receive electrical stimulation treatment with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Total n=56 Participants Total of all reporting groups
Age, Categorical <=18 years	0 Participants n=93 Participants	0 Participants n=4 Participants	0 Participants n=27 Participants
Age, Categorical Between 18 and 65 years	15 Participants n=93 Participants	16 Participants n=4 Participants	31 Participants n=27 Participants
Age, Categorical >=65 years	14 Participants n=93 Participants	11 Participants n=4 Participants	25 Participants n=27 Participants
Age, Continuous	64.1 years STANDARD_DEVIATION 8.5 • n=93 Participants	62.2 years STANDARD_DEVIATION 7.6 • n=4 Participants	63.2 years STANDARD_DEVIATION 8.1 • n=27 Participants
Sex: Female, Male Female	25 Participants n=93 Participants	19 Participants n=4 Participants	44 Participants n=27 Participants
Sex: Female, Male Male	4 Participants n=93 Participants	8 Participants n=4 Participants	12 Participants n=27 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	2 Participants n=93 Participants	0 Participants n=4 Participants	2 Participants n=27 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	27 Participants n=93 Participants	27 Participants n=4 Participants	54 Participants n=27 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=93 Participants	0 Participants n=4 Participants	0 Participants n=27 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=93 Participants	0 Participants n=4 Participants	0 Participants n=27 Participants
Race (NIH/OMB) Asian	2 Participants n=93 Participants	1 Participants n=4 Participants	3 Participants n=27 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=93 Participants	0 Participants n=4 Participants	0 Participants n=27 Participants
Race (NIH/OMB) Black or African American	10 Participants n=93 Participants	4 Participants n=4 Participants	14 Participants n=27 Participants
Race (NIH/OMB) White	17 Participants n=93 Participants	22 Participants n=4 Participants	39 Participants n=27 Participants
Race (NIH/OMB) More than one race	0 Participants n=93 Participants	0 Participants n=4 Participants	0 Participants n=27 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=93 Participants	0 Participants n=4 Participants	0 Participants n=27 Participants
Region of Enrollment United States	29 Participants n=93 Participants	27 Participants n=4 Participants	56 Participants n=27 Participants
Employment Status Currently Working	6 Participants n=93 Participants	11 Participants n=4 Participants	17 Participants n=27 Participants
Employment Status Retired (not due to health)	13 Participants n=93 Participants	8 Participants n=4 Participants	21 Participants n=27 Participants
Employment Status Unemployed	3 Participants n=93 Participants	2 Participants n=4 Participants	5 Participants n=27 Participants
Employment Status Disabled / Retired (due to health)	7 Participants n=93 Participants	5 Participants n=4 Participants	12 Participants n=27 Participants
Employment Status Other (Retired (not due to health) and employed part-time)	0 Participants n=93 Participants	1 Participants n=4 Participants	1 Participants n=27 Participants

PRIMARY outcome

Timeframe: Baseline and 5 to 8 weeks post-Start of Treatment (SOT)

Population: Full Analysis Set presented. To account for missing data due to missed visits and early terminations, data were also imputed using a mixed-effects model.

Outcome measures

Outcome measures
Measure	Group 1 (Treatment) n=20 Participants Participants in Group 1 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received electrical stimulation for up to 8 weeks with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 (Control) n=21 Participants Participants in Group 2 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received up to 8 weeks of sham stimulation. Three months after start of sham treatment, participants were given the option to crossover and receive electrical stimulation treatment with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 Crossover Safety Set Participants who were consented, randomized to Group 2 (Control), received sham stimulation treatment, and crossed over to receive electrical stimulation via the SPRINT Peripheral Nerve Stimulation (PNS) System.
Reduction in Average Pain Intensity: Number of Participants With ≥ 50% Reduction in Average Pain Intensity	12 Participants	5 Participants	—

PRIMARY outcome

Timeframe: Up to 13 months for each Group 1 participant and up to 16 months for Group 2 participants that opted to cross over (time from baseline to last study visit)

Population: Safety Analysis Set presented.

At each study visit following the baseline assessment at Visit 1, participants were questioned if any changes in their medical status or condition have occurred since their previous visit. If the participant experienced a change that was a study-related adverse event, an Adverse Event Form was completed by the site. The number of participants that experienced at least one study-related adverse event is reported here. Adverse Events are reported by the trial phase in which they occurred: Group 1 Treatment (active stimulation), Group 2 Control (sham stimulation), and Group 2 Crossover Safety Set (active stimulation).

Outcome measures

Outcome measures
Measure	Group 1 (Treatment) n=28 Participants Participants in Group 1 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received electrical stimulation for up to 8 weeks with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 (Control) n=27 Participants Participants in Group 2 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received up to 8 weeks of sham stimulation. Three months after start of sham treatment, participants were given the option to crossover and receive electrical stimulation treatment with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 Crossover Safety Set n=11 Participants Participants who were consented, randomized to Group 2 (Control), received sham stimulation treatment, and crossed over to receive electrical stimulation via the SPRINT Peripheral Nerve Stimulation (PNS) System.
Study-Related Adverse Device Effects	9 Participants	14 Participants	5 Participants

SECONDARY outcome

Timeframe: Baseline and 1 to 4-weeks post-start of treatment (SOT)

Population: Full Analysis Set presented.

All participants were asked to complete daily diaries to record their average knee pain intensity during the past 24 hours on each day of a 7-day period using an 11-point numerical rating scale where 0 represents "No Pain" and 10 represents "Pain as bad as you can imagine." The average pain score was calculated across the 7-day diary(s) at baseline and across weeks 1 to 4 post-start of treatment. Percent reduction was then calculated for each participant. To be considered a success, participants must have experienced ≥ 50% reduction in average knee pain. The number of successes is presented.

Outcome measures

Outcome measures
Measure	Group 1 (Treatment) n=20 Participants Participants in Group 1 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received electrical stimulation for up to 8 weeks with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 (Control) n=21 Participants Participants in Group 2 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received up to 8 weeks of sham stimulation. Three months after start of sham treatment, participants were given the option to crossover and receive electrical stimulation treatment with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 Crossover Safety Set Participants who were consented, randomized to Group 2 (Control), received sham stimulation treatment, and crossed over to receive electrical stimulation via the SPRINT Peripheral Nerve Stimulation (PNS) System.
Reduction in Average Pain Intensity: Number of Participants With ≥ 50% Reduction in Average Pain Intensity	7 Participants	3 Participants	—

SECONDARY outcome

Timeframe: Baseline, 3-months post-start of treatment (SOT), 6-months post-SOT, 9-months post-SOT, 12-months post-SOT

Population: Full Analysis Set presented. According to the planned study protocol, Group 2 was not assessed for this outcome at 6, 9, and 12-months due to crossover to receive active stimulation. To account for missing data due to missed visits and early terminations, data were also imputed using a mixed-effects model for Group 2 at 3-months post-SOT and for Group 1 at 6, 9, and 12-months post-SOT.

All participants were asked to complete daily diaries to record their average knee pain intensity during the past 24 hours on each day of a 7-day period using an 11-point numerical rating scale where 0 represents "No Pain" and 10 represents "Pain as bad as you can imagine." The average pain score was calculated across the 7-day diary for each participant at baseline and at 3-, 6-, 9-, and 12-months post-start of treatment. Percent reduction was then calculated for each participant. To be considered a success, participants must have experienced ≥ 50% reduction in average knee pain. The number of successes is presented.

Outcome measures

Outcome measures
Measure	Group 1 (Treatment) n=20 Participants Participants in Group 1 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received electrical stimulation for up to 8 weeks with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 (Control) n=21 Participants Participants in Group 2 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received up to 8 weeks of sham stimulation. Three months after start of sham treatment, participants were given the option to crossover and receive electrical stimulation treatment with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 Crossover Safety Set Participants who were consented, randomized to Group 2 (Control), received sham stimulation treatment, and crossed over to receive electrical stimulation via the SPRINT Peripheral Nerve Stimulation (PNS) System.
Long-term Durability of Average Pain Relief: Number of Participants With ≥ 50% Reduction in Average Pain Intensity 3-months Post-SOT	10.00 participants (with imputed values)	5.00 participants (with imputed values)	—
Long-term Durability of Average Pain Relief: Number of Participants With ≥ 50% Reduction in Average Pain Intensity 6-months Post-SOT	9.96 participants (with imputed values)	—	—
Long-term Durability of Average Pain Relief: Number of Participants With ≥ 50% Reduction in Average Pain Intensity 9-months Post-SOT	9.02 participants (with imputed values)	—	—
Long-term Durability of Average Pain Relief: Number of Participants With ≥ 50% Reduction in Average Pain Intensity 12-months Post-SOT	10.36 participants (with imputed values)	—	—

SECONDARY outcome

Timeframe: Baseline, 1 to 4-weeks post-start of treatment (SOT), 5 to 8-weeks post-SOT, 3-months post-SOT, 6-months post-SOT, 9-months post-SOT, and 12-months post-SOT

All participants were asked to complete daily diaries to record their average knee pain intensity during the past 24 hours on each day of a 7-day period using an 11-point numerical rating scale where 0 represents "No Pain" and 10 represents "Pain as bad as you can imagine." The mean pain score was calculated across the 7-day diary(s) for each participant at baseline, 1-4 weeks post-start of treatment (SOT), 5-8 weeks post-SOT, and at 3-, 6-, 9-, and 12-months post-SOT. The mean pain score is presented.

Outcome measures

Outcome measures
Measure	Group 1 (Treatment) n=20 Participants Participants in Group 1 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received electrical stimulation for up to 8 weeks with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 (Control) n=21 Participants Participants in Group 2 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received up to 8 weeks of sham stimulation. Three months after start of sham treatment, participants were given the option to crossover and receive electrical stimulation treatment with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 Crossover Safety Set Participants who were consented, randomized to Group 2 (Control), received sham stimulation treatment, and crossed over to receive electrical stimulation via the SPRINT Peripheral Nerve Stimulation (PNS) System.
Mean Pain Relief Baseline	7.26 score on a scale (with imputed values) Standard Deviation 1.24	7.21 score on a scale (with imputed values) Standard Deviation 1.44	—
Mean Pain Relief 1 to 4 weeks Post-SOT	4.37 score on a scale (with imputed values) Standard Deviation 2.02	5.65 score on a scale (with imputed values) Standard Deviation 2.16	—
Mean Pain Relief 5 to 8 weeks Post-SOT	3.32 score on a scale (with imputed values) Standard Deviation 2.18	5.34 score on a scale (with imputed values) Standard Deviation 2.56	—
Mean Pain Relief 3-months Post-SOT	3.69 score on a scale (with imputed values) Standard Deviation 2.67	5.37 score on a scale (with imputed values) Standard Deviation 2.76	—
Mean Pain Relief 6-months Post-SOT	4.04 score on a scale (with imputed values) Standard Deviation 2.78	—	—
Mean Pain Relief 9-months Post-SOT	4.00 score on a scale (with imputed values) Standard Deviation 2.71	—	—
Mean Pain Relief 12-months Post-SOT	4.15 score on a scale (with imputed values) Standard Deviation 2.75	—	—

SECONDARY outcome

Timeframe: Baseline, 1 to 4 weeks post-start of treatment (SOT), and 5 to 8 weeks post-SOT, 3-months post-SOT, 6-months post-SOT, 9-months post-SOT, and 12-months post-SOT

Population: Full Analysis Set presented. According to the planned study protocol, Group 2 was not assessed for this outcome at 6, 9, and 12-months due to crossover to receive active stimulation. Participants that did not report any pain medications during the study were excluded. Data were not available for one Group 2 participant at 3-months post-SOT, five Group 1 participants at 6-months post-SOT, three Group 1 participants at 9-months post-SOT, and six Group 1 participants at 12-months post-SOT.

Participants recorded the amount/type of analgesics used in daily diaries. A blinded, third-party medication committee reviewed participants' diary medications for each time period to determine if each participant's analgesic usage changed. The committee determined whether there was No change (no change in dosage or change is not clinically meaningful to impact pain outcomes), an Increase (clinically meaningful increase in medication that would impact pain outcomes), or a Decrease (clinically meaningful decrease in medication that would impact pain outcomes) for each time period compared to baseline. The number of participants with a Decrease in analgesic medication usage for pain are reported. Participants that did not report any pain medications during the study were excluded from the analysis.

Outcome measures

Outcome measures
Measure	Group 1 (Treatment) n=17 Participants Participants in Group 1 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received electrical stimulation for up to 8 weeks with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 (Control) n=20 Participants Participants in Group 2 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received up to 8 weeks of sham stimulation. Three months after start of sham treatment, participants were given the option to crossover and receive electrical stimulation treatment with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 Crossover Safety Set Participants who were consented, randomized to Group 2 (Control), received sham stimulation treatment, and crossed over to receive electrical stimulation via the SPRINT Peripheral Nerve Stimulation (PNS) System.
Pain Medication Usage 12-months post-SOT	4 Participants	—	—
Pain Medication Usage 1 to 4 weeks post-SOT	8 Participants	9 Participants	—
Pain Medication Usage 5 to 8 weeks post-SOT	11 Participants	10 Participants	—
Pain Medication Usage 3-months post-SOT	8 Participants	8 Participants	—
Pain Medication Usage 6-months post-SOT	5 Participants	—	—
Pain Medication Usage 9-months post-SOT	4 Participants	—	—

SECONDARY outcome

Timeframe: Baseline (Visit 1), 4-weeks post-SOT (Visit 6), and 8-weeks post-SOT (Visit 10)

Population: Full Analysis Set presented. Data were not available for one Group 1 participant and two Group 2 participants at 4-weeks post-SOT and for one Group 2 participant at 8-weeks post-SOT.

The Pain Catastrophizing Scale (PCS) questionnaire has 13 questions that assess rumination, magnification, and helplessness. Participants are asked to think back on painful experiences in the past and reflect on how often they had specific thoughts or feelings. Each of the 13 questions is scored on a 5-point scale where 0 represents "not at all," and 4 represents "all the time." The scores from each question were summed for each participant to provide a total PCS score, with a possible range from 0 to 52 with higher scores indicating a greater tendency to catastrophize pain (i.e. a higher score indicates a worse outcome). The mean score for each time point is presented.

Outcome measures

Outcome measures
Measure	Group 1 (Treatment) n=20 Participants Participants in Group 1 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received electrical stimulation for up to 8 weeks with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 (Control) n=21 Participants Participants in Group 2 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received up to 8 weeks of sham stimulation. Three months after start of sham treatment, participants were given the option to crossover and receive electrical stimulation treatment with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 Crossover Safety Set Participants who were consented, randomized to Group 2 (Control), received sham stimulation treatment, and crossed over to receive electrical stimulation via the SPRINT Peripheral Nerve Stimulation (PNS) System.
Pain Catastrophizing Scale (PCS) Visit 1: Baseline	24.30 score on a scale Standard Deviation 12.92	27.14 score on a scale Standard Deviation 16.81	—
Pain Catastrophizing Scale (PCS) Visit 6: 4-weeks Post-SOT	12.53 score on a scale Standard Deviation 11.41	16.47 score on a scale Standard Deviation 14.63	—
Pain Catastrophizing Scale (PCS) Visit 10: 8-weeks Post-SOT	9.30 score on a scale Standard Deviation 8.29	14.75 score on a scale Standard Deviation 14.35	—

SECONDARY outcome

Timeframe: 4-weeks post-start of treatment (SOT)(Visit 6), 8-weeks post-SOT (Visit 10), 3-months post-SOT (Visit 11), 6-months post-SOT (Visit 12), 9-months post-SOT (Visit 13), and 12-months post-SOT (Visit 14)

Population: Full Analysis Set presented. According to the planned study protocol, Group 2 was not assessed for this outcome at 6, 9, and 12-months due to crossover to receive active stimulation. Missing data due to missed visits and early terminations were also imputed using a mixed-effects model for outcomes at 6, 9, and 12-months post-SOT. Data were not available for one Group 1 and two Group 2 participants at 4-weeks, one Group 2 participant at 8-weeks, and one Group 2 participant at 3-months post-SOT.

The Patient Global Impression of Change (PGIC) Survey asks participants to rate their improvement with treatment on a 7-point scale ranging from -3 to 0 to +3, where -3 represents "very much worse," 0 is "no change," and +3 represents "very much improved" as compared to before stimulation treatment. The participants combine all the components of their experience into one overall score. The mean score of each group was calculated for each time frame.

Outcome measures

Outcome measures
Measure	Group 1 (Treatment) n=20 Participants Participants in Group 1 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received electrical stimulation for up to 8 weeks with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 (Control) n=21 Participants Participants in Group 2 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received up to 8 weeks of sham stimulation. Three months after start of sham treatment, participants were given the option to crossover and receive electrical stimulation treatment with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 Crossover Safety Set Participants who were consented, randomized to Group 2 (Control), received sham stimulation treatment, and crossed over to receive electrical stimulation via the SPRINT Peripheral Nerve Stimulation (PNS) System.
Patient Global Impression of Change (PGIC) Visit 6: 4-weeks Post-SOT	1.42 score on a scale (with imputed values) Standard Deviation 1.22	1.05 score on a scale (with imputed values) Standard Deviation 0.97	—
Patient Global Impression of Change (PGIC) Visit 10: 8-weeks Post-SOT	1.80 score on a scale (with imputed values) Standard Deviation 1.06	1.15 score on a scale (with imputed values) Standard Deviation 1.18	—
Patient Global Impression of Change (PGIC) Visit 11: 3-months Post-SOT	1.75 score on a scale (with imputed values) Standard Deviation 1.16	0.75 score on a scale (with imputed values) Standard Deviation 1.25	—
Patient Global Impression of Change (PGIC) Visit 12: 6-months Post-SOT	1.32 score on a scale (with imputed values) Standard Deviation 1.49	—	—
Patient Global Impression of Change (PGIC) Visit 13: 9-months Post-SOT	1.01 score on a scale (with imputed values) Standard Deviation 1.58	—	—
Patient Global Impression of Change (PGIC) Visit 14: 12-months Post-SOT	1.11 score on a scale (with imputed values) Standard Deviation 1.36	—	—

SECONDARY outcome

Timeframe: Baseline (Visit 1), 8-weeks post-start of treatment (SOT) (Visit 10), 3-months post-SOT (Visit 11), 6-months post-SOT (Visit 12), 9-months post-SOT (Visit 13), and 12-months post-SOT (Visit 14)

Population: Full Analysis Set presented. According to the planned study protocol, Group 2 was not assessed for this outcome at 6, 9, and 12-months due to crossover to receive active stimulation. For participants that completed treatment, missing data due to missed visits and early terminations were also imputed using a mixed-effects model at 6, 9, and 12-months post-SOT. Data were not available for one Group 2 participant at 8-weeks and 3-months post-SOT.

Question 9 of the Brief Pain Inventory-Short Form (BPI-9) is a 7-part question that assesses the level of interference that participants experience in their daily lives due to pain. The 7 categories are general activity, mood, walking ability, normal work, relations with other people, sleep, and enjoyment of life. Participants were asked to rate how much their post-surgical knee pain interferes with each aspect on an 11-point numerical scale where 0 represents "Does Not Interfere" and 10 represents "Completely Interferes." The average of these 7 scores was calculated for each participant at each time point. Percent reduction was then calculated for each participant. To be considered a success, participants must have experienced ≥ 50% reduction in pain interference. The number of successes is presented.

Outcome measures

Outcome measures
Measure	Group 1 (Treatment) n=20 Participants Participants in Group 1 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received electrical stimulation for up to 8 weeks with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 (Control) n=21 Participants Participants in Group 2 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received up to 8 weeks of sham stimulation. Three months after start of sham treatment, participants were given the option to crossover and receive electrical stimulation treatment with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 Crossover Safety Set Participants who were consented, randomized to Group 2 (Control), received sham stimulation treatment, and crossed over to receive electrical stimulation via the SPRINT Peripheral Nerve Stimulation (PNS) System.
Pain Interference: Number of Participants With ≥ 50% Reduction in Pain Interference Visit 10: 8-weeks Post-SOT	13.00 participants (with imputed values)	11.00 participants (with imputed values)	—
Pain Interference: Number of Participants With ≥ 50% Reduction in Pain Interference Visit 11: 3-months Post-SOT	11.00 participants (with imputed values)	6.00 participants (with imputed values)	—
Pain Interference: Number of Participants With ≥ 50% Reduction in Pain Interference Visit 12: 6-months Post-SOT	11.20 participants (with imputed values)	—	—
Pain Interference: Number of Participants With ≥ 50% Reduction in Pain Interference Visit 13: 9-months Post-SOT	11.16 participants (with imputed values)	—	—
Pain Interference: Number of Participants With ≥ 50% Reduction in Pain Interference Visit 14: 12-months Post-SOT	11.14 participants (with imputed values)	—	—

SECONDARY outcome

Population: Full Analysis Set presented. According to the planned study protocol, Group 2 was not assessed for this outcome at 6, 9, and 12-months due to crossover to receive active stimulation. For participants that completed treatment, missing data due to missed visits and early terminations were also imputed using a mixed-effects model at 6, 9, and 12-months post-SOT. Data were not available for one Group 2 participant at 8-weeks and 3-months post-SOT.

The Western Ontario and McMaster University Osteoarthritis Index (WOMAC) questionnaire consists of 24 items that evaluate pain, stiffness, and physical functional disability. Each item is scored on an 11-point numerical rating scale from 0 to 10, where higher scores indicate greater pain, stiffness, and disability. For each participant, the scores from each of the 24 items were averaged to calculate the participant's total score, with a minimum score of 0 and a maximum score of 10. The mean total score was then calculated across participants and percent reduction was calculated for each time point. To be considered a success, participants must have experienced ≥ 33% reduction in their score. The number of successes is presented.

Outcome measures

Outcome measures
Measure	Group 1 (Treatment) n=20 Participants Participants in Group 1 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received electrical stimulation for up to 8 weeks with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 (Control) n=21 Participants Participants in Group 2 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received up to 8 weeks of sham stimulation. Three months after start of sham treatment, participants were given the option to crossover and receive electrical stimulation treatment with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 Crossover Safety Set Participants who were consented, randomized to Group 2 (Control), received sham stimulation treatment, and crossed over to receive electrical stimulation via the SPRINT Peripheral Nerve Stimulation (PNS) System.
Function (i.e., Physical Recovery) Visit 10: 8-weeks Post-SOT	16.00 participants (with imputed values)	11.00 participants (with imputed values)	—
Function (i.e., Physical Recovery) Visit 11: 3-months Post-SOT	13.00 participants (with imputed values)	9.00 participants (with imputed values)	—
Function (i.e., Physical Recovery) Visit 12: 6-months Post-SOT	11.42 participants (with imputed values)	—	—
Function (i.e., Physical Recovery) Visit 13: 9-months Post-SOT	12.22 participants (with imputed values)	—	—
Function (i.e., Physical Recovery) Visit 14: 12-months Post-SOT	11.08 participants (with imputed values)	—	—

SECONDARY outcome

Timeframe: Baseline (Visit 1), 8-weeks post-start of treatment (SOT) (Visit 10), and 3-months post-SOT (Visit 11)

Population: Full Analysis set presented. Data were unavailable for two Group 1 participants and one Group 2 participant at 8-weeks post-SOT and for four Group 1 participants and one Group 2 participant at 3-months post-SOT.

The total distance that a participant could walk in 6 minutes was recorded, and participants unable to walk at all were given a score of 0 meters. The mean distance was then determined across participants. The baseline score was compared to the score at the specified intervals after start of therapy.

Outcome measures

Outcome measures
Measure	Group 1 (Treatment) n=20 Participants Participants in Group 1 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received electrical stimulation for up to 8 weeks with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 (Control) n=21 Participants Participants in Group 2 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received up to 8 weeks of sham stimulation. Three months after start of sham treatment, participants were given the option to crossover and receive electrical stimulation treatment with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 Crossover Safety Set Participants who were consented, randomized to Group 2 (Control), received sham stimulation treatment, and crossed over to receive electrical stimulation via the SPRINT Peripheral Nerve Stimulation (PNS) System.
Six Minute Walk Test (6MWT) Visit 1: Baseline	267.29 meters Standard Deviation 108.91	291.94 meters Standard Deviation 91.12	—
Six Minute Walk Test (6MWT) Visit 10: 8-weeks Post-SOT	354.29 meters Standard Deviation 197.63	253.36 meters Standard Deviation 142.77	—
Six Minute Walk Test (6MWT) Visit 11: 3-months Post-SOT	318.11 meters Standard Deviation 164.83	269.77 meters Standard Deviation 156.50	—

Adverse Events

Group 1 (Treatment)

Serious events: 0 serious events

Other events: 9 other events

Deaths: 0 deaths

Group 2 (Control)

Serious events: 0 serious events

Other events: 14 other events

Deaths: 0 deaths

Group 2 Crossover Safety Set

Serious events: 0 serious events

Other events: 5 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Other adverse events
Measure	Group 1 (Treatment) n=28 participants at risk Participants in Group 1 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received electrical stimulation for up to 8 weeks with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 (Control) n=27 participants at risk Participants in Group 2 were consented and met all eligibility criteria prior to randomization. These participants had leads placed in their mid to upper thigh and received up to 8 weeks of sham stimulation. Three months after start of sham treatment, participants were given the option to crossover and receive electrical stimulation treatment with the SPRINT Peripheral Nerve Stimulation (PNS) System.	Group 2 Crossover Safety Set n=11 participants at risk Participants who were consented, randomized to Group 2 (Control), received sham stimulation treatment, and crossed over to receive electrical stimulation via the SPRINT Peripheral Nerve Stimulation (PNS) System.
Musculoskeletal and connective tissue disorders Pain at lead site	3.6% 1/28 • Number of events 1 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.	0.00% 0/27 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.	0.00% 0/11 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.
Skin and subcutaneous tissue disorders Skin irritation	25.0% 7/28 • Number of events 7 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.	40.7% 11/27 • Number of events 15 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.	36.4% 4/11 • Number of events 5 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.
Skin and subcutaneous tissue disorders Itching at bandage, pad, and/or lead exit sites	7.1% 2/28 • Number of events 3 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.	11.1% 3/27 • Number of events 3 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.	18.2% 2/11 • Number of events 2 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.
Skin and subcutaneous tissue disorders Discoloration/bruising at lead exit site	3.6% 1/28 • Number of events 1 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.	7.4% 2/27 • Number of events 2 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.	0.00% 0/11 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.
Skin and subcutaneous tissue disorders Skin tear at bandage or connector site	0.00% 0/28 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.	7.4% 2/27 • Number of events 2 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.	0.00% 0/11 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.
Skin and subcutaneous tissue disorders Granuloma	0.00% 0/28 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.	0.00% 0/27 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.	9.1% 1/11 • Number of events 1 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.
Musculoskeletal and connective tissue disorders Exacerbation of existing pain	0.00% 0/28 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.	3.7% 1/27 • Number of events 1 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.	0.00% 0/11 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.
Musculoskeletal and connective tissue disorders Uncomfortable stimulation	0.00% 0/28 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.	0.00% 0/27 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.	9.1% 1/11 • Number of events 1 • Each participant enrolled was assessed for adverse events from the time of informed consent through their final study visit. For Group 1, the total assessment period was approximately 13 months for each participant. Each Group 2 participant that did not crossover to receive stimulation treatment was assessed through their study participation (approximately 3 months). Group 2 participants that crossed over to receive treatment were each assessed for approximately 16 months.

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