Why there is no number at the top of this page
ARC does not publish a success rate. A trial's response rate belongs to that trial's population — its entry criteria, its treated nerves, its follow-up window — and quoting it on a marketing page turns a finding about a studied group into an implied promise to you. The physician who examines you is the person who can say what the evidence means for your case.
What can be said honestly is what the trials report and where to read them. Peripheral nerve stimulation has been studied in multiple clinical trials and peer-reviewed publications in patients with chronic pain who had not responded adequately to conservative treatment, and those studies report meaningful pain reduction in the populations they followed.
What the published follow-up reports
The longest public follow-up for implantable PNS currently runs to two years. A 2026 summary of 24-month outcomes from the COMFORT randomized trial reported durable, clinically meaningful pain relief in the cohort that completed follow-up, together with improvements in disability, depression scores, and quality of life. Read it yourself rather than taking a summary's word for it. Source: Practical Neurology, https://practicalneurology.com/news/implantable-peripheral-nerve-stimulation-shows-durable-pain-relief-at-24-months/2485516/ — primary publication: Engle MP et al., https://doi.org/10.29011/2576-957X.100079
Joint-specific evidence is thinner than the overall evidence, and the subgroups that trials report by treated region are smaller than their full cohorts. That is a reason to ask a specific question at a consultation, not a reason to discount the therapy.
Measuring success
Success in PNS is measured across several dimensions: pain reduction (using standardized pain scales), functional improvement (ability to perform daily activities), medication reduction, and patient satisfaction.
Pain relief alone doesn't tell the full story. Many patients report improvements in sleep quality, mood, activity levels, and overall quality of life — benefits that compound over time as chronic pain patterns are disrupted.
Durability of results
Implantable PNS is built for continued use when it helps, and published trial follow-up now extends through 24 months for some systems. The COMFORT study analysis summarized in Practical Neurology (2026) reported sustained, clinically meaningful pain improvement at two years in the followed cohort. Source: https://practicalneurology.com/news/implantable-peripheral-nerve-stimulation-shows-durable-pain-relief-at-24-months/2485516/
Because PNS modulates nerve signaling rather than delivering a drug that wears off, its durability profile is different from many injections or short medication courses — though individual responses still vary.
Who responds best
Patients who tend to see the strongest outcomes are those with chronic joint pain and preserved joint anatomy — meaning the joint structure itself hasn't fully deteriorated. Patients who have tried conservative treatments without lasting relief but aren't yet at the point of needing replacement are the core population.
Your physician will evaluate your specific situation to set realistic expectations. Not every patient responds identically, and honest assessment of likely outcomes is a core part of the ARC approach.
The low-risk profile
Beyond effectiveness, PNS carries a favorable safety profile. Serious adverse events are rare. The most common side effects are mild and temporary — localized soreness at the insertion site being the most frequently reported. The reversibility of PNS means that even in cases where relief is insufficient, the patient retains all future treatment options.