Freedom-1 Study for Chronic Knee Pain

  • End date
    Oct 22, 2024
  • participants needed
  • sponsor
    Stimwave Technologies
Updated on 4 October 2022


To demonstrate the potential benefits and risk of active sub-threshold stimulation in the treatment of chronic knee pain as compared to subjects that did not have active stimulation. Improvement will be assessed in relation to the clinical outcome measures of pain, with primary endpoint; Pain relief rate as measured by the number of subjects with greater or equal to a 50% decrease in pain on the visual analog scale, comparing baseline to the 1-month follow-up.


This will be a multi-center, prospective, sham-controlled, double blinded, randomized clinical study.

A total of eighty evaluable (80) subjects with unilateral arthritic knee pain will be recruited into this clinical trial from multiple sites. Enrollment will continue until 80 subjects have evaluable primary endpoints. Some subjects will not pass the 1-week trial period, and others may be lost to follow-up. The Principal Investigator (PI) will screen all of the subjects for appropriateness for the procedure. The degree of neuropathic pain will be assessed using the DN4 standard questionnaire. 29 A diagnostic injection of the IPS under ultrasound, fluoroscopy or landmark guided in the clinic will be performed, and only those subjects with significant temporary pain relief (> 75%) for at least 2 hours will be allowed to continue with the study. All subjects will be brought to the procedure room or operating room (OR) for the trial implant procedure under local anesthetic. An introducer will be placed under ultrasound or fluoroscopic guidance at the target nerve and the electrodes percutaneously advanced towards the IPS. After insertion of the receiver and then confirmation of stimulation, the trial stimulator will be secured to the skin. The stimulator tail will be outside the body and attached to the skin. All subjects will undergo an active 7-day provisional test period. Only those subjects reporting > 50% pain relief at the end of the 7-day provisional test period as compared to baseline will be allowed to continue with the study. The trial leads will be removed at the end of 7 days.

All subjects responding to therapy with > 50% pain relief at 7 days will, at a later date, be brought to the operating room (OR) and given a sedative and local anesthetic. An introducer will be placed under ultrasound or fluoroscopic guidance onto the target nerve and the electrode array advanced towards the nerve. The receiver will be mated with the electrode array, and, after confirmation of stimulation, the permanent stimulator will be tunneled and secured. The subject will then be randomized to either active sub-threshold (high frequency) stimulation or no stimulation (sham). All subjects and assessors will be blinded to the group assignment for up to three months follow-upFollow-up visits will be conducted at 1 week, 1 month, 3 months, and 6 months post-implantation. Follow up phone calls at 12 months, 18 months, and 24 months post-implantation will be performed to confirm durability of pain relief with a verbal rating scale (VRS; 0-100) and global perceived effects scale (GPES) and to capture any subject-reported adverse events.

Initial and follow-up evaluations will consist of physical exams, visual analog scales (VRS at 12, 18, 24 months), Western Ontario and McMasters University Arthritis Score (WOMAC), range of motion (flexion and extension measured by goniometer, work status and medication intake evaluation. At 1-month post-permanent implant, if there is not >50% relief, the subject will be unblinded. If sham was confirmed, the stimulator will then be reprogrammed to receive active treatment, and the trial continued. If the active arm was confirmed, the stimulator will be reprogrammed, and the trial continued. All subjects will be unblinded at the 3-month visit regardless of randomization and outcome. If sham was confirmed, the stimulator will then be reprogrammed to receive active treatment Available stimulation programs include tonic (on table testing), burst, 1000 Hz 1499 Hz frequency stimulation, all of which may be utilized via the same subject.

Condition Osteoarthritic Knee Pain
Treatment Wireless neuromodulation
Clinical Study IdentifierNCT03877653
SponsorStimwave Technologies
Last Modified on4 October 2022


Yes No Not Sure

Inclusion Criteria

Subject is over 18 years of age
Subjects with a history of chronic, function-limiting (VAS >5/10) knee pain from osteoarthritis of at least three months in duration with or without prior surgeries
Subject has been diagnosed with Kellgren-Lawrence Grade II or III knee osteoarthritis, confirmed by X-ray studies conducted in the last year
Subject has been examined and has been deemed to be an appropriate candidate for the procedure, including chronic knee pain in patients post total knee replacement (TKR)
Subjects who are able to understand this investigation and give voluntary, written informed consent to participate in this study
Subjects who, in the opinion of the Investigator, are able to understand this investigation, are able to co-operate with the study procedures and are willing to return to the center for all the required post-operative follow-ups
Documented failure of at least two less invasive treatment modalities and medications including physical therapy, intra-articular steroids and/or oral NSAIDS
Subject has not had recent surgical procedures of the knee within the last three months
Subject noted good (> 75%) but only temporary relief for at least 2 hours from an infrapatellar saphenous nerve injection with local anesthetic;-
Subject is deemed to be neuro-psycho-socially appropriate for implantation therapies based of assessment of a Clinical Psychologist, using face-to-face encounters and psychological testing measures

Exclusion Criteria

Significant contralateral knee pain that would influence their level of activity greater to two on a scale to ten
Hip or foot pain greater than knee pain
Neurogenic or vascular claudication
Subject has been diagnosed with Kellgren-Lawrence Grade IV knee osteoarthritis, confirmed by X-ray studies conducted in the last year
Uncontrolled major depression or uncontrolled psychiatric disorders
Uncontrolled or acute medical illnesses including coagulopathy, renal insufficiency, chronic liver dysfunction, progressive neurological deficit, infection, unstable angina, and severe chronic obstructive pulmonary disease
Chronic severe conditions that could interfere with the interpretations of the outcome assessments for pain and bodily function (eg. Rheumatoid arthritis, severe spinal stenosis, activity-limiting cardiac disease)
Women who are pregnant or planning to become pregnant, lactating
Body mass index (BMI) greater than 40 (morbid obesity)
Subjects with multiple complaints involving concomitant knee, foot, or ankle pathology or radiculopathy, that will not be amenable to study due to the overlap of pain complaints
Subject has been examined and has been deemed to be inappropriate for the procedure based on anatomical restrictions
Lymphedema or stasis ulcers or other conditions that would compromise the surgical site
History of adverse reaction to local anesthetic drugs
Worker's compensation claimants
Incarcerated or has an ankle position locator
Subject noted no relief from a local anesthetic injection of infrapatellar saphenous nerve
Documented allergy to device material components
Participation in another clinical study that could confound the results of this study
Based on the opinion of the investigator any legal or medical concerns that would preclude his/her enrollment in the study or potentially confound the results
Known or suspected substance abuse within the last 2 years
Pacemaker or implanted defibrillator
Any other implanted active medical devices in the same site
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