Clinical Trial of the MiniStim PNS for Knee Pain- "FLEX" Study

This is a prospective, multi-center, randomized, study in which 300 evaluable subjects will be randomized 1:1 to receive active or delayed therapy with Moments PNS. Subjects in the Delayed group will start with therapy at 3-month visit follow up. The primary endpoint is a \>50% pain relief at 3-months as measured by the Visual Analog Scale (VAS) without increase in baseline pain medications, with additional measurements assessed at 3, 6, 9, 12, 24, and 36-months.

This is a prospective, randomized, controlled, multi-center study in which up to 300 evaluable subjects will receive MiniStim PNS. Target subjects will have chronic knee pain.

Subjects will be randomized into either the active or delayed group. Devices will be activated post-op in accordance to the randomization assignment. Subjects randomized to the Active group, programming parameters will be set, and therapy will be delivered for a minimum of 2-hours per day for the duration of the study. Implanted subjects will be educated on the use of the transmitter. Programming changes can be done as needed during this time period to maximize clinical response according to pre-programmed settings. Subjects randomized to the Delayed group will begin 2-hour stimulation/day at the 3-Month visit.

The primary endpoint will be at 3-Months, comparing Active vs. Delayed data from baseline data, and subjects in the Delay group will begin stimulation. At the 3-month visit, VAS will be completed and compared to baseline VAS, during this visit the safety and efficacy of the device will be assessed, and subjects in the Delayed group will be instructed to begin daily stimulation for a minimum of 2 hours a day. Subjects will be seen at 3-month intervals through the 12-Month visit for data collection and adverse event review. Subjects will continue therapy and followed for a total of 36-months with primary outcomes assessed at 3-months. Their participation in the study will end at 36-months.

Eligibility Criteria:
Inclusion Criteria:

A. Capable of giving informed consent and willing to follow all study related procedures;

B. Women and men \>18 years of age;

C. Baseline VAS score of \> 5;

D. History of chronic, function-limiting knee pain of at least three months;

E. Not had recent surgical procedures of the knee within the last three months;

F. ≥50% temporary relief from temporary nerve diagnostics;

G. No evidence of anatomic abnormalities that could jeopardize the placement of the device;

H. Able to operate programmer, recharger, study assessments and provide accurate responses;

I. Appropriate candidate for the implant procedure based on the opinion of investigator.

Exclusion Criteria:

A. An active implantable electronic device regardless of whether stimulation is ON or OFF;

B. Dependency on utilizing wearable or transcutaneous monitoring device (hearing aids, continuous glucose monitors, etc.);

C. Pregnant as confirmed by a urine pregnancy test or plan to become pregnant during study;

D. Subject noted no relief from temporary nerve diagnostics;

E. Inability to achieve appropriate positioning;

F. Inability to understand informed consent and protocol;

G. Conditions requiring recurring MRI evaluation or diathermy procedures;

H. Anatomical restrictions such that device placement is not possible;

I. Have a life expectancy of less than 1-year;

J. Worker's compensation claimants;

K. Based on opinion of investigator any legal concerns that would preclude his/her enrollment in the study or potentially confound results;

L. Deemed unsuitable for enrollment by investigator based on medical history or physical examination.