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

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.