The X-Ray Is Perfect and the Knee Still Burns: What a 60-Day Nerve Stimulator Is Actually Testing

What this video covers

• How a single injured nerve drives ongoing pain, how the spinal cord amplifies that signal, and the proposed mechanism by which stimulation closes the pain gate
• How a fine coiled lead is placed percutaneously under ultrasound guidance, without an implanted battery
• Why relief sometimes persists after the 60-day lead is removed, what the follow-up data does and does not establish, and why durability beyond a year is not yet known
• What the randomized trials found — and which of them were blinded — in chronic low back pain, post-knee-replacement pain, and post-amputation pain
• How peripheral nerve stimulation differs from spinal cord stimulation, and when each is appropriate
• The real risks: skin irritation, itching at the dressing, and superficial infection at the lead exit site
• MEDICAL DISCLAIMER: This content is for educational purposes only and is not medical advice. It does not substitute for professional diagnosis or treatment. Always consult a licensed healthcare provider regarding your condition. Viewing this video does not establish a doctor-patient relationship.

Fourteen months after a total knee replacement, the X-ray is perfect. No loosening, no infection, nothing a surgeon can see. And the knee still burns — a band of fire across the front, a leg that cannot take stairs. You were told the surgery was a success, and then you were told to accept this.

This article explains a category of treatment that sits between a pill bottle and a permanent implant: a fine temporary wire placed near a single nerve, worn for sixty days, and then pulled back out. It covers what the wire is proposed to do, why a nerve can keep firing long after the tissue has healed, what the randomized trials actually found — and, just as importantly, where the evidence stops.

Peripheral nerve stimulation is not a general pain treatment

This is the first thing to get straight, because confusing it is the commonest reason the treatment fails.

Peripheral nerve stimulation (PNS) has two distinct uses. The first is pain generated or carried by a single identifiable nerve — a branch of the femoral or sciatic distribution left firing after a knee replacement, or the nerves of a residual limb after amputation. The second is a different application entirely: stimulation of the lumbar medial branches for axial low back pain, aimed at driving deep spinal stabilizer muscles that have shut down. That second use is not about quieting one painful nerve; it is a motor application that works by a different route.

If your pain is neither — if it is widespread, whole-body, and not traceable to a target — a lead is a selection error, not a treatment.

The proposed mechanism, with its hedges

Here is the model, stated at the confidence the data supports and no further.

A fine lead placed near the target nerve delivers low-amplitude current. At that amplitude it preferentially recruits large-diameter myelinated fibers — the fibers that carry touch and position sense — rather than the small unmyelinated fibers that carry pain. That input is believed to engage inhibitory interneurons in the dorsal horn of the spinal cord and to recruit descending modulation from the brain.

That is the gate-control model. It is a model.

There is a second, bolder claim attached to the sixty-day system: that relief can outlast the wire, and that this carry-over reflects a genuine reduction in central sensitization. That mechanism is hypothesized. It has not been demonstrated directly in humans. As Dr. Gurpreet Singh Padda, MD, MBA, MHP puts it in the video, anyone who states it as settled fact is selling you something.

Why the knee still burns when the imaging is clean

Surgery is controlled trauma. Dissection, retraction, and thermal injury can leave a branch of a peripheral nerve firing when it should be silent — spontaneous discharge with no injury left to report.

That barrage arrives at the dorsal horn, and the dorsal horn turns the gain up. Thresholds drop. Inhibitory tone falls away. Ordinary touch begins to register as pain. That is central sensitization, and it is why the felt experience and the film can disagree so completely.

It also explains the shape of the symptom. The pain is a band of burning rather than a deep ache, because it follows a nerve’s territory and not a joint’s. The sheet on the knee at night is intolerable, because the amplification does not distinguish light touch from injury. Stairs are impossible, because a quadriceps guarded for two years has wasted. And once amplification is established, injecting a perfectly good knee changes nothing — you are treating a joint that is no longer the problem.

What standard care leaves out

Nothing here is an accusation against any physician. It is a description of a gap.

The system has two speeds for nerve pain. Speed one is medication — gabapentin, then duloxetine, then a shrug. Speed two is a permanent implant: hardware that stays in your body, a generator in a pocket under the skin, a device that will eventually need service, replacement, or removal. Sometimes a permanent system is exactly right. But it is a large decision to make first, before anyone has confirmed that stimulating a nerve helps you at all.

Between those two speeds, most patients are offered nothing.

Part of the reason is timing: the sixty-day percutaneous system is newer, and its randomized data has only landed in the last few years. Part of it is that a temporary wire is a smaller procedure than an implant, and smaller procedures get discussed less. The point is not why you were not offered it. The point is that the category exists, and the evidence is now good enough that it should have been named.

What the procedure actually involves

Most people hear “neuromodulation” and picture a battery buried in their back. This is not that.

Under ultrasound, the needle is watched in real time as it travels to the target nerve. A coiled wire thinner than a pencil lead is threaded percutaneously to sit near the nerve, not against it. There is no incision and no implanted battery. The lead exits the skin to a small external pulse generator worn on a strap for sixty days, and then it is withdrawn in the office. The step-by-step procedure detail, including what to expect at placement and removal, is on the peripheral nerve stimulation treatment page.

The lead is engineered to come out whole, and in the great majority of cases it does. Dr. Padda names one consent point on camera anyway: a fine coiled wire that has sat in tissue for two months can, rarely, separate on removal and leave a fragment. That was not among the adverse events reported in the largest trial — treat it as a risk the physician raises at consent, not as a published rate.

What the randomized trials actually show

Three trials carry this treatment. They are worth reading carefully rather than in headline form.

The knee replacement trial — the only double-blind one

Goree and colleagues, in Neuromodulation in 2024, ran the trial that matters most methodologically: randomized, double-blind, placebo-controlled.[1] Both groups had real leads placed under ultrasound at the femoral and sciatic nerves, identically. Only one group’s device delivered current. Neither the patients nor the designated evaluator knew which.

Sixty percent of the stimulation arms (12 of 20) reached at least 50% pain relief, against 24% (5 of 21) with sham (p = 0.028). Read the timing carefully: the leads were indwelling for eight weeks and the primary endpoint was measured over weeks five to eight, while the wires were still in place. That number says stimulation worked. It is not evidence that relief outlasted removal.

Walking distance improved 47% in the stimulation arms while the sham group declined 9% — but that is a secondary outcome, measured on fewer patients (18 vs 20 completing the test), at a p-value sitting right on the line (p = 0.048). It does not carry the primary endpoint’s weight. Forty-one patients were randomized in all.

RESET — larger, more pragmatic, and unblinded

McCormick and colleagues published RESET in Pain Medicine in 2026: 230 patients, sixty-day lumbar medial branch stimulation against usual interventional care for chronic low back pain.[2] Fifty-five percent versus 26% reached at least 50% relief at three months, sustained through six months.

Be careful with that 55%. Blinding was not possible after randomization — this was an open-label trial, so expectation effects cannot be excluded when the patient can feel the device running. And the trial excluded a great many people: radiating leg pain, prior lumbar spine surgery, a body mass index over 40, and anyone who had undergone radiofrequency ablation of those same medial branches within six months. If you are in one of those groups, 55% is not your number. Nobody has measured your number.

Amputation — twelve months, but only nine patients

Gilmore and colleagues, in Regional Anesthesia and Pain Medicine in 2020, followed traumatic lower-limb amputees.[3] Twenty-eight were randomized: one group to eight weeks of stimulation, the other to four weeks of placebo and then a crossover to four weeks of stimulation. Six of the nine stimulation patients still being followed at twelve months responded, against none of fourteen in the placebo group.

That comparison is not what it looks like at first glance. The placebo group’s zero was measured at its own four-week endpoint, before those patients crossed over to stimulation. There was no twelve-month control arm, and the nine is what was left of the stimulation group at a year rather than the number enrolled. The authors themselves concluded only that sixty-day stimulation may provide carry-over effects.

What all three have in common

Two of the three trials enrolled fewer than 45 patients. All three were sponsored or staffed by the device manufacturer. RESET’s primary funding came from the U.S. Department of Defense, with additional funding from the study’s sponsor. None of that invalidates the results. It is context you are entitled to have before you weigh them.

And the honest limit on durability: the longest published follow-up is twelve months, in nine patients. Beyond a year, nobody knows.

What this means for evaluation

The question is not whether you want a stimulator

It is whether your pain traces to a nerve. Selection runs on a differential, and each branch has to be ruled in or out: intact hardware versus loosening or low-grade periprosthetic infection; radicular pain from a nerve root versus peripheral pain from a nerve; complex regional pain syndrome; or widespread nociplastic pain that no single lead can touch.

A diagnostic ultrasound-guided block of the candidate nerve is what settles it. If numbing that nerve does not move your pain, that nerve is probably not carrying it — and a lead should not be placed on hope. Probably is deliberate. A block can fail technically, and more than one nerve can feed a region. A negative block sends the physician back to the differential, not to a refusal.

What sixty days are actually like

Expect to be annoyed for two months. In the largest trial — the 230-patient low back study — mild skin irritation occurred in about 31.5% of participants, itching under the dressing in about 19.8%, superficial skin infection in 2.7% per lead exit site, and granulomas in 1.4% per lead exit site. Roughly 8% had pain from the device itself and about 5% reported discomfort, along with some muscle spasms and stinging. All were non-serious; no serious, unanticipated study-related adverse events occurred.[2]

Practically: the exit site has to stay dry. No baths, no swimming, for two months.

What a good result looks like

The following is an illustrative composite — a picture assembled from many patients with this condition, not one person’s chart, and not a patient testimonial.

Two years out from a knee replacement. Burning across the front of the knee, sleep broken most nights, a quadriceps wasted by two years of guarding the leg. Two surgeons had declined revision, correctly — there was nothing to revise. A diagnostic block localized the generator. What was hard: the itching under the dressing, keeping the exit site dry, and week three, when relief was only partial and doubt set in.

Walking did not come back on its own. A device does not build a quadriceps; eight weeks of loading a leg that had been guarded for two years is what turned relief into stairs. At six months the pain was better. It was not gone. A leg that carries you up a staircase and still complains at the top is what a good result looks like here. Some people get less, usually those whose pain was never truly focal. Individual results vary.

And if the pain comes back

Then the sixty days were not wasted. You now have an answer to the only question that mattered — whether stimulating that nerve helps you. That is what turns a permanent system into a reasoned decision instead of a gamble.

Frequently asked questions

Key takeaways

• Peripheral nerve stimulation treats pain generated or carried by a single identifiable nerve — plus a separate lumbar medial branch application for axial low back pain. It is not a treatment for widespread pain, and selection is the biggest determinant of whether it works.
• The gate-control explanation is a model, not a demonstrated fact, and carry-over relief after the lead is removed has not been shown directly in humans to result from reduced central sensitization.
• The evidence is real but narrow: one double-blind sham-controlled trial in 41 patients after knee replacement (60% vs 24%, measured while the leads were still in place), one larger but open-label trial in 230 patients with low back pain (55% vs 26%, with substantial exclusions), and a twelve-month amputation follow-up resting on nine patients with no twelve-month control. All three were sponsored or staffed by the device manufacturer, and durability beyond a year is unknown.
• The sixty-day wire is diagnostic as well as therapeutic: it answers whether stimulating that nerve helps you before anyone implants permanent hardware.
• The question worth bringing to an evaluation is not whether you want a stimulator, but whether your pain traces to a nerve — and a diagnostic ultrasound-guided block is what answers it.

Medically reviewed by Gurpreet Singh Padda, MD — Board Certified in Anesthesiology, Pain Medicine, Interventional Pain Management, Addiction Medicine, and Obesity Medicine. Last reviewed July 2026.

This article is educational and is not a substitute for evaluation, diagnosis, or treatment by a physician. Individual results vary. Do not start, stop, or change any medication without consulting your physician. To be evaluated at the Padda Institute Center for Interventional Pain Management, call (314) 481-5000 or text (314) 886-5902.

References

1. McCormick ZL, Lester DD, DePalma MJ, Gilmore CA, Li S, Jameson JB, Desai MJ, Weaver TE, Lad SP, Davidoff SJ, Trainor DM, Amirdelfan K, Engle MP, Deer TR, Lee TS, Vetri F, Bindal M, Tornero-Bold MA, Nasseri MN, Cohen SP, Clark WH, McGee MJ, Boggs JW. Comparison of percutaneous 60-day peripheral nerve stimulation of the lumbar medial branches to usual care with standard interventional management for chronic low back pain – a multicenter pragmatic randomized controlled trial (RESET). Pain Med. 2026 Apr 1;27(4):462-473. PMID 4113817410109314713061121. PubMed
2. Goree JH, Grant SA, Dickerson DM, Ilfeld BM, Eshraghi Y, Vaid S, Valimahomed AK, Shah JR, Smith GL, Finneran JJ, Shah NN, Guirguis MN, Eckmann MS, Antony AB, Ohlendorf BJ, Gupta M, Gilbert JE, Wongsarnpigoon A, Boggs JW. Randomized Placebo-Controlled Trial of 60-Day Percutaneous Peripheral Nerve Stimulation Treatment Indicates Relief of Persistent Postoperative Pain, and Improved Function After Knee Replacement. Neuromodulation. 2024 Jul;27(5):847-861. PMID 38739062101016202403001. PubMed
3. Gilmore CA, Ilfeld BM, Rosenow JM, Li S, Desai MJ, Hunter CW, Rauck RL, Nader A, Mak J, Cohen SP, Crosby ND, Boggs JW. Percutaneous 60-day peripheral nerve stimulation implant provides sustained relief of chronic pain following amputation: 12-month follow-up of a randomized, double-blind, placebo-controlled trial. Reg Anesth Pain Med. 2020;45(1):44-51. PMID 317404431011362019100937. PubMed

Dr. Gurpreet Singh Padda, MD, MBA, MHP