Study of StimRouter for Chronic Knee OA Pain

The goal of this study is to evaluate the use of StimRouter Neuromodulation System (StimRouter) in adult subjects with an established diagnosis of primary femorotibial osteoarthritis in the target knee (Kellgren-Lawrence ≥1) who have surgical contraindications to undergo a knee joint arthroplasty procedure. The main questions it aims to answer are:

1. To assess the effect of the StimRouter Neuromodulation System to manage joint pain in patients with symptomatic OA of the knee who are surgically contraindicated to undergo a knee joint arthroplasty
2. To assess the effect of StimRouter on joint stiffness, function and patient quality of life

Participants will have StimRouter leads implanted then clinic visits will be scheduled for follow-up at Week 2, Month 3 and Month 6 (End of Study (EOS) or Early Termination (ET)).

This study will be a single-center, single-arm, open label pilot study evaluating the safety and efficacy of the StimRouter Neuromodulation System as a peripheral nerve stimulator targeting knee joint innervation of moderately to severely symptomatic subjects with OA of the knee who are non-eligible to undergo a joint arthroplasty at the target knee.

Up to 30 subjects will be enrolled and participate in the study. Clinic visits will be scheduled at Screening, Stimulation Trial Procedure, Trial Assessment Visit, Implant Procedure and Follow-up Week 2, Month 3 and Month 6 (End of Study (EOS) or Early Termination (ET)).

Eligibility Criteria:
Inclusion Criteria:

1. Subject is at least 21 years of age at the time of giving informed consent
2. Radiographic disease Stage ≥ 1 in the target knee according to the Kellgren-Lawrence grading of knee OA
3. Knee joint arthroplasty procedure is contraindicated
4. Full understanding of the requirements of the study and willingness to comply with all study visits and assessments
5. Subjects must have read and understood the informed consent form, and must have signed it prior to any study-related procedure being performed

Exclusion Criteria:

1. Subject has undergone previous joint arthroplasty procedure (partial, total, patella-femoral) to the index knee
2. Unresolved effusion of the target knee clinically requiring aspiration within 12 weeks prior to Visit 1 (Baseline)
3. Treatment of the index knee with systemic or intra-articular corticosteroids (e.g., methylprednisolone) within 6 weeks prior to Visit 1 (Baseline)
4. Visco-supplementation (e.g., hyaluronic acid) in the index knee within 6 weeks prior to Visit 1 (Baseline)
5. Subject has an active systemic infection or an active local infection in or near the index knee joint, or has a previous history of joint infection.
6. Subject with bleeding disorders or active anticoagulation that cannot be stopped for a few days prior to the time of the surgical procedure.
7. Subject who has an active or existing skin disorder or irritation, which, in the opinion of the Investigator, precludes the use of skin gel electrodes.
8. Subjects has or plans to have a pacemaker, defibrillator, cochlear implant, and/or a sleep apnea implant.
9. Subject has or plans to have a Spinal Cord Stimulator (SCS), Peripheral Nerve field Stimulation system (PNfS), Dorsal Root Ganglion system (DRG), or implantable infusion pump.
10. Subject who currently requires or is likely to require Magnetic Resonance Imaging (MRI) within the MRI exclusion zone: the entire PNS lead must be at least 50 cm from the center of the MRI system's bore (the iso-center) and at least 16 cm outside of the MRI coil measured from the edge of the MRI coil.
11. Female subject who is pregnant or nursing or plans to become pregnant during the study. The effects of electrical stimulation on pregnancy are not known. Do not use electrical stimulation (including StimRouter) during pregnancy.
12. Any condition and findings in the medical history or in the pre-study assessments, that in the opinion of the Investigator, constitutes a risk or contraindication for participation in the study or that could interfere with the study objectives, conduct, or evaluation
13. Comorbid conditions that could affect pain assessment of the target knee, including, but not limited to, inflammatory rheumatic conditions such as rheumatoid arthritis, psoriatic arthritis, systemic lupus erythematosus