Physiotherapy Treatments Using Interferential Therapy

Interferential therapy (IFT) is an electrotherapy technique that passes two medium-frequency electrical currents through the skin so they intersect in the tissue and produce a low-frequency therapeutic “beat” at depth. It is comfortable, it is safe when properly screened — and, for the three conditions it is most often used for, NICE recommends that it should not be offered. That is an uncomfortable thing for a physiotherapy clinic to publish, but it is what the current UK guidance says, and you deserve to know it before you pay for treatment. This guide explains honestly what IFT is, the physics of how it works, what the parameters and electrode placements actually do, where the evidence is genuinely positive (post-operative knee rehabilitation), where NICE says not to use it, its side effects and contraindications in full, and what the evidence does support instead. Written by the chartered physiotherapy team at CK Physio in Hanwell, West London.

What is interferential therapy, and what does IFT stand for?

IFT stands for interferential therapy, also called interferential current therapy or IFC. It is a form of electrotherapy introduced to clinical practice in the early 1950s by Dr Hans Nemec, an Austrian physicist who wanted to deliver the therapeutic effects of low-frequency electrical stimulation without the skin discomfort that low frequencies cause.

His solution was ingenious. Rather than pushing a low-frequency current through the skin, IFT uses two medium-frequency currents that cross inside the body. Where they meet, they interfere with one another and produce a low-frequency therapeutic signal at depth — the “interference” the name refers to. The skin only ever encounters the comfortable medium-frequency carriers.

IFT became one of the most widely used electrotherapy modalities in physiotherapy clinics worldwide. Understanding it properly matters — but so does understanding what the evidence has since shown, which is where this guide differs from most.

What does NICE say about interferential therapy?

NICE explicitly names interferential therapy in “do not offer” recommendations in three separate guidelines, covering osteoarthritis, low back pain and sciatica, and chronic primary pain. We are putting this near the top rather than burying it near the bottom, because if you are searching for IFT you are probably deciding whether to have it.

Two points of precision matter here, and we want to be exact rather than dramatic.

First, NICE’s objection is to a lack of evidence of benefit, not to safety. None of these guidelines describes interferential therapy as dangerous or categorises it as unsafe. The judgement is that the clinical benefit does not justify the resource when better-supported alternatives exist.

Second, “do not offer for osteoarthritis, low back pain and chronic primary pain” is not the same as “IFT never works for anything”. Those three guidelines cover a great deal of musculoskeletal practice, which is why this is significant. But they do not cover every clinical situation, and there is one area — early post-operative knee rehabilitation — where the evidence is genuinely more encouraging. We cover that properly below rather than pretending it does not exist.

How does IFT work? Carrier frequency, beat frequency and the physics

IFT works by exploiting the fact that skin resists high-frequency current far less than low-frequency current, then recreating a low-frequency signal inside the body where the two carrier currents intersect. This is the part that is genuinely well established physics, and it is worth understanding properly.

Skin — particularly the stratum corneum — behaves as a resistive-capacitive barrier whose impedance falls as frequency rises. Empirical estimates cited in electrotherapy teaching put skin impedance at roughly 3,200 Ω at 50 Hz, falling to around 40 Ω at 4,000 Hz. That is a dramatic reduction, and it is the entire reason medium frequency is used: for a given voltage, far more current crosses the skin, so adequate current reaches deeper tissue without the stinging that low-frequency stimulation produces at the surface.

The carriers themselves are not intended to stimulate nerve or muscle — nerve membranes cannot follow alternations that rapid. Their job is simply to get through the skin. The therapeutic effect comes from interference. If one channel delivers frequency f₁ and the other f₂, then where the currents overlap the resultant amplitude rises and falls at the beat frequency:

This beat frequency — usually called the amplitude-modulated frequency (AMF) — behaves like low-frequency stimulation as far as nerve depolarisation is concerned, despite being carried by medium-frequency waveforms. AMF is typically adjustable between 1 and 250 Hz, and it is the parameter most closely tied to clinical intent.

Two mechanisms are proposed for the analgesia. At higher beat frequencies (roughly 80–150 Hz) the intention is to stimulate large-diameter Aβ sensory fibres and close the “pain gate” described by Melzack and Wall — the same rationale as high-frequency TENS. At lower beat frequencies with stronger intensities, the intention is to recruit descending inhibitory pathways and endogenous opioid release. Both are plausible and consistent with wider electrotherapy science — but neither has been demonstrated experimentally with IFT specifically. A 2022 review of interferential current analgesia noted that, despite decades of clinical use, there has been no experimental research directly investigating IFT’s mechanism of action for pain relief. The mechanisms are borrowed from TENS research.

Is the “deep cross-fire” claim actually true?

Partly. The comfort and depth advantage of medium frequency is real; the idea that IFT precisely targets a deep crossing point is an oversimplification. This distinction matters because it is one of the most repeated claims in electrotherapy teaching and marketing.

The classic teaching model describes a “clover-leaf” field in quadripolar arrangements, with the strongest beat current along diagonals and a peak where the currents cross — hence instructions to position the target tissue at the central crossing point. More recent analysis shows this inadequately reflects how current behaves in real tissue. Current does not travel in straight lines between electrodes; it spreads three-dimensionally along paths of least resistance, shaped by the conductivity of fat, muscle and fascia, electrode size and spacing, and even posture during treatment. Modelling and measurement suggest the interference pattern is far more diffuse, with significant beat current generated near the skin and across a broad volume.

Tim Watson’s electrotherapy reference makes the practical point: while higher current density along diagonals can be observed, assuming that most of the therapeutic effect happens at a single deep point is misleading, and clinicians should regard the whole volume between and beneath the electrodes as the stimulated region. There is also a straightforward empirical check — if IFT really delivered substantially more effective current to deep structures while sparing the skin, it should outperform TENS. It does not, as we explain below.

IFT parameters: carrier frequency, beat frequency, sweep and intensity

Conventional parameter ranges are well established in clinical teaching — but their evidential foundation is weaker than their confident presentation suggests. The table below sets out what is typically used and, honestly, how well supported each choice is.

Carrier frequency is usually set between 2,000 and 4,000 Hz, with 4 kHz a common default. Higher carriers are more comfortable; interestingly, one review found that carriers of 1 or 4 kHz combined with a 100 Hz AMF appeared to produce greater analgesia than higher, more comfortable carrier frequencies — suggesting a possible trade-off between comfort and effect. Beyond that, there is no strong evidence that one setting within the usual range is superior.

Sweep (or spectrum/scan) modes vary the beat frequency over time within a set band — for example 90–110 Hz for pain or 10–25 Hz for motor work. The rationale is to reduce nerve accommodation to a constant stimulus. It is theoretically appealing and some patients find it more comfortable, but there is limited evidence that sweep outperforms a constant beat frequency, and reviews find that parameter variations including sweep do not show a consistent influence on analgesic outcomes.

Intensity is titrated on patient feedback, not a number. The convention is “strong but comfortable”: increase until there is a definite prickling or tingling, allow a few minutes for accommodation, increase again until slight muscle contraction appears, then reduce until it stops. For motor goals the intensity is deliberately taken above motor threshold to produce tolerable rhythmic contractions. Trials typically report intensity as a sensation rather than in measurable current, which is one reason the literature is so hard to compare.

Duration and course. Sessions are usually 10–20 minutes, with conventional teaching advising no more than 20 minutes to a single area and 30 minutes in total. Courses are often two to three times weekly. In UK private practice IFT is normally a portion of a longer appointment rather than the whole of it. There is no evidence that longer sessions produce better analgesia. If several properly dosed sessions produce no meaningful change, continuing is difficult to justify.

IFT electrode placement: bipolar, quadripolar and cross-fire

There are two fundamental configurations: bipolar, where the interference is created inside the machine, and quadripolar, where it is created inside your tissue.

Bipolar (premodulated) IFT uses two electrodes on a single channel. The two medium-frequency currents are mixed within the device before delivery, so the patient receives an already-modulated low-frequency current without true in-tissue interference. The field is relatively static and oval, which suits smaller areas such as an ankle or elbow.

Quadripolar IFT uses four electrodes across two channels, each carrying a medium-frequency current, with the interference occurring where the paths cross inside the tissue. This is the classic arrangement, and the one associated with the clover-leaf field description. Vector or scan modes add controlled variation between channels so the zone of maximal interference appears to move through the area.

In practice, quadripolar “cross-fire” arrangements are used for deeper or more diffuse problems — electrodes placed diagonally around a lumbar segment or a knee so the currents intersect within the region, forming a square around it with the target tissue in the middle. Bipolar placement is used for more localised problems, with the two electrodes either side of a small joint.

Larger electrodes are generally more comfortable and distribute current more evenly; smaller electrodes concentrate it. Skin preparation matters — clean skin, adequate conductive gel or properly moistened sponges, full even contact with no air gaps, and avoidance of bony prominences where current density rises and discomfort follows.

Honest caveat: there is very little data comparing bipolar with quadripolar in terms of actual outcomes. The theoretical advantages of quadripolar arrangements have not been robustly tested against bipolar, many trials do not report electrode configuration at all, and Watson suggests the distinction between “true” interferential and premodulated IFT may matter less than once believed, since both ultimately deliver a low-frequency modulated current through the skin.

What does the evidence actually show, condition by condition?

The pattern across the literature is consistent: IFT often beats sham or no treatment slightly in the short term, rarely beats other active treatments, and adds little or nothing on top of exercise. Two Cochrane reviews and several systematic reviews frame the picture.

Knee osteoarthritis — Cochrane CD002823. This review of transcutaneous electrostimulation included 18 small trials and 813 patients, four of which used interferential current and one both IFC and TENS. Methodological and reporting quality were poor, heterogeneity was high (I² = 80%) and the funnel plot was asymmetrical, suggesting publication bias. The predicted standardised mean difference for pain was −0.07 (95% CI −0.46 to 0.32) — equivalent to about 0.2 cm on a 10 cm visual analogue scale. There was no evidence that effects differed by type of electrostimulation. The authors concluded they “could not confirm that transcutaneous electrostimulation is effective for pain relief”.

Neck pain — Cochrane CD004251. Twenty small trials, 1,239 people, covering several modalities including interferential current. The authors were unable to make definitive statements about efficacy or clinical usefulness because for every outcome the quality of evidence was low or very low. No outcome had high or moderate strength of evidence. In whiplash-associated disorder, one trial found no difference between treated and untreated patients for neck pain and headache.

Shoulder pain. A 2023 randomised study in subacromial impingement is particularly instructive. Fifty-two patients received hot pack plus exercise, and were randomised to add IFT, TENS, or sham IFT — five times weekly for three weeks, 15 sessions of 20 minutes. All groups improved significantly in pain, range of movement and function. There were no statistically significant differences between groups. Adding real IFT achieved nothing beyond the hot pack and exercise. An earlier trial similarly found no effect of bipolar interferential therapy for soft tissue shoulder disorders.

Chronic low back pain. Several trials show short-term pain reduction versus sham, typically with ~100 Hz beat frequencies, but the magnitude is small and often clinically marginal, with follow-up limited to weeks. IFT does not consistently outperform TENS, manual therapy or exercise. NICE NG59 names interferential therapy in a “do not offer” recommendation for this condition.

A health technology assessment reviewing RCTs and meta-analyses across musculoskeletal and non-musculoskeletal conditions took a more sceptical position still, concluding that IFT generally does not significantly improve outcomes compared with placebo or other therapies, and classifying interferential current stimulation as investigational. And a recurring methodological problem runs through the whole literature: IFT is usually added on top of active treatment, so the active treatment does the work and the modality’s specific contribution is hard to isolate.

Where IFT does have better evidence: post-operative knee rehabilitation

There is one indication where the evidence is genuinely more encouraging, and it would be dishonest to omit it: early rehabilitation after knee surgery.

A randomised, double-blind, placebo-controlled trial published in the Clinical Journal of Sport Medicine studied 87 patients undergoing anterior cruciate ligament reconstruction, meniscectomy or knee chondroplasty. Participants were randomised to active home interferential units or placebo units delivering no current, with outcomes tracked to eight weeks. The active IFT group reported significantly less pain, had significantly greater range of movement at all post-operative time points, experienced significantly less swelling (in the ACL and meniscectomy groups at all times, and in the chondroplasty group up to four weeks), and took less pain medication.

That is a well-designed trial with clinically meaningful outcomes, and it deserves its weight. The honest qualifications: replication is limited, it is essentially one major trial, broader post-operative data are mixed, longer-term functional benefit beyond the early weeks is not clearly demonstrated, and cryotherapy, compression, analgesia and above all exercise also drive post-operative recovery. So the fair summary is that in the first weeks after knee surgery, IFT may reasonably be considered a helpful adjunct for pain and swelling — supporting active rehabilitation, not replacing it.

IFT vs TENS: what is the difference?

The technical differences are real; the difference in results is not. A 2018 systematic review and meta-analysis pooled eight studies and 825 patients comparing the two directly, with moderate methodological quality (mean PEDro 6/10). Both improved pain and function, with no statistically significant difference between them for acute or chronic pain, and no difference in disability outcomes either. If you want a fuller account of TENS specifically, see our guide to using TENS as physiotherapy treatment for pain conditions.

The practical implication is worth stating plainly: since results are comparable, TENS has a genuine advantage for anyone wanting ongoing symptom control — it is inexpensive, portable and supports self-management at home, whereas IFT requires repeat clinic attendance. If a modality is going to help you, the one you can use yourself is usually the better buy.

IFT side effects: what can actually happen

Interferential therapy has a good safety record and serious adverse events are rare, but it is not side-effect free — and reporting in the research literature is poor enough that confident incidence figures do not exist.

Skin reactions under the electrodes are the most common problem. Transient itching, redness, or a burning sensation can occur, particularly if electrode contact is uneven, intensity is too high, or the skin was not properly cleaned. These usually settle within hours to days. A 2024 study demonstrated that electrical stimulation measurably increases skin permeability and erythema in response to irritants, meaning stimulated skin is temporarily more vulnerable than normal skin. For context, previous work found that roughly 40% of TENS users develop contact dermatitis beneath electrodes with continuous use — IFT has not been quantified in large prospective cohorts, but the electrode mechanics are similar enough that the order of magnitude is probably comparable with repeated sessions. Risk rises with poor electrode hygiene, degraded adhesive, latex sensitivity, and application over hair-bearing or sweaty skin.

Discomfort and, very rarely, burns. Sharp or stinging sensations are a sign of something wrong — poor contact, inappropriate parameters or a bad electrode site — rather than an inherent feature of treatment. Electrical burns are rare in modern practice and typically require a gross technical failure: faulty equipment, damaged electrodes, exposed conductive surfaces, or a clinician ignoring a patient’s report of pain. They are most dangerous where sensation is impaired and the patient cannot feel the problem developing.

Dizziness and systemic effects are uncommon but documented. A 2012 case report described a patient having IFT for severe shoulder pain who was also taking tramadol: after each session he experienced loss of concentration, drowsiness, reduced alertness, gait disturbance and dizziness lasting four to five hours. The authors hypothesised potentiation of opioid effect. It is a single case, but the practical lesson is sound — tell your physiotherapist what medication you take, particularly opioids or sedatives.

Temporary symptom flare. A mild increase in soreness or fatigue after treatment can happen, especially if there was muscle activation, and should settle within 24 hours. If pain worsens significantly or persists beyond that, the treatment should be reviewed rather than repeated.

An honest note on the evidence itself: major reviews of TENS and electrotherapy have repeatedly found that adverse events are under-reported, with most trials failing to document harms systematically. One overview concluded it could not determine with confidence whether TENS is harmful or benign because the reporting was insufficient. Serious harm appears rare — but “no evidence of harm” and “evidence of no harm” are different things, and we would rather say so.

What the evidence does support: active rehabilitation

If interferential therapy is not the answer for osteoarthritis, back pain or chronic pain, the obvious question is what is — and the answer is consistent across every relevant NICE guideline: active, exercise-based rehabilitation, education and self-management.

This is not a consolation prize. It is the intervention with the strongest evidence in musculoskeletal care, and the shoulder trial described earlier illustrates why: the hot pack and exercise produced the improvement, and the electrotherapy added nothing measurable on top. The active component was doing the work all along.

In practice that means a proper assessment to establish what is actually driving your symptoms, a progressive exercise programme matched to your capacity and goals, load and activity management so you keep moving without flaring things up, and clear explanation so you understand what is happening and what to expect. For chronic primary pain, NICE recommends psychologically informed approaches such as acceptance and commitment therapy or cognitive behavioural therapy delivered by trained clinicians — reflecting a decisive shift towards active and psychosocial care and away from passive modalities.

This is also the direction of travel across UK physiotherapy generally. Availability and use of electrophysical agents has been declining as services concentrate on interventions with stronger evidence, and many NHS musculoskeletal services now use IFT sparingly or not at all. If you want the wider context on electrotherapy as a family of treatments, see our guides to what electrotherapy is and how it works and the benefits and limits of electrotherapy in physiotherapy. If knee osteoarthritis is your concern, our NICE-aligned guide to knee osteoarthritis physiotherapy sets out what the guidance does recommend.

There is one electrotherapy-adjacent modality where the evidence is genuinely strong for specific indications, and it is worth naming for balance: extracorporeal shockwave therapy (ESWT). NICE interventional procedure guidance supports its use for calcific tendinopathy of the shoulder, and there is good randomised evidence in plantar fasciitis. That is a meaningfully different evidence position from IFT, and we offer it on site — see our complete guide to shockwave therapy.

What a session feels like, and what to expect

IFT should never hurt. Most people describe a tingling, pulsing or prickling sensation under the electrodes, often quite pleasant, sometimes with a mild rhythmic muscle twitch if motor-level settings are used. Electrodes are positioned around the area, intensity is increased gradually until the sensation is clear but comfortable, and treatment usually runs for 10–20 minutes within a longer appointment that includes assessment, hands-on treatment and exercise.

Before treatment your physiotherapist should screen the contraindications above, inspect your skin, and test sensation in the area — because safe dosing depends on your feedback. During treatment, say something immediately if you feel anything sharp, burning, or increasingly uncomfortable, or if you feel light-headed or nauseated. Afterwards the skin is checked for redness. If IFT is going to help you, that will usually be apparent within a few sessions; if several properly dosed sessions change nothing, continuing is not justified and your time is better spent on rehabilitation that works.

How CK Physio approaches this in Hanwell and West London

We have electrotherapy on site, including interferential therapy — and we will tell you honestly when it is not the right answer for your problem. That is the whole point of publishing this guide in the form you have just read it.

What you get at CK Physiotherapy is an assessment-led appointment: a thorough history, a physical examination, a clear explanation of what we think is going on, and a rehabilitation plan built around active treatment. If your condition is one where NICE advises against interferential therapy — osteoarthritis, low back pain or chronic primary pain — we will say so and spend your session on what the evidence supports instead. If you are in the early weeks after knee surgery, where the evidence for IFT is stronger, we may offer it as an adjunct alongside your rehabilitation programme, with realistic expectations set at the outset.

Our physiotherapists are HCPC-registered and members of the Chartered Society of Physiotherapy, and we have been treating musculoskeletal problems across Hanwell, Ealing and West London since 2003. Sessions are £65–£95 for self-paying patients, we are recognised by BUPA and AXA PPP, and home visits are available across the W5, W7 and W13 postcodes. You will find us at 57 Elthorne Avenue, Hanwell, W7 2JY — you can also read more about physiotherapy at our West London clinic.

NHS musculoskeletal physiotherapy is a good route and many trusts accept self-referral, though waits vary considerably by area. Whichever route you take, the thing that determines your outcome is not which machine gets used — it is getting an accurate assessment and then doing the rehabilitation consistently.

Frequently asked questions about interferential therapy

What does IFT stand for in physiotherapy?

IFT stands for interferential therapy, also known as interferential current therapy or IFC. It is a form of electrotherapy that passes two medium-frequency electrical currents (typically 2,000–4,000 Hz) through the skin from separate electrode pairs. Where these currents intersect inside the tissue they interfere with one another, producing a low-frequency “beat” frequency — usually between 1 and 250 Hz — which is the part that affects nerves. The technique was introduced in the early 1950s by Dr Hans Nemec, whose aim was to deliver the effects of low-frequency stimulation without the skin discomfort it normally causes, since skin impedance falls sharply as frequency rises.

Does NICE recommend interferential therapy?

No. NICE explicitly names interferential therapy in “do not offer” recommendations in three guidelines: NG226 for osteoarthritis (recommendation 1.3.9, alongside TENS, ultrasound, laser, pulsed short-wave and NMES, “because there is insufficient evidence of benefit”), NG59 for low back pain and sciatica (recommendation 1.2.12), and NG193 for chronic primary pain (recommendation 1.2.6, “because there is no evidence of benefit”). Importantly, the objection is to insufficient evidence of benefit rather than to safety — NICE does not describe IFT as unsafe. It is also worth being precise: these recommendations cover osteoarthritis, low back pain and chronic primary pain, and do not amount to a statement that IFT never has any use. The evidence in early post-operative knee rehabilitation, for example, is more encouraging.

What are the side effects of IFT in physiotherapy?

The most common side effects are skin reactions beneath the electrodes: transient itching, redness, or a burning sensation, usually settling within hours to days. Research shows electrical stimulation temporarily increases skin permeability and sensitivity to irritants, and around 40% of TENS users develop contact dermatitis under electrodes with continuous use, which is likely comparable for IFT with repeated sessions. Electrical burns are rare and generally require a technical failure such as faulty equipment, damaged electrodes or an unheeded report of pain. Dizziness and drowsiness are uncommon; one case report described prolonged drowsiness and dizziness in a patient having IFT while taking tramadol, so tell your physiotherapist about any opioid or sedative medication. A mild temporary increase in soreness can occur and should settle within 24 hours. Honestly, adverse events are under-reported across the electrotherapy literature, so confident incidence figures do not exist — serious harm appears rare, but that is not the same as proven safety.

What are the contraindications to interferential therapy?

Absolute contraindications include cardiac pacemakers, implantable defibrillators, neurostimulators and other implanted electronic devices; application over the anterior neck or carotid sinus; over or near the eyes; active deep vein thrombosis or thrombophlebitis; known or suspected malignancy in the treatment field; the low back or abdomen during pregnancy; active infection, tuberculosis or wounds with underlying osteomyelitis; broken or compromised skin that conducts current unevenly; impaired skin sensation or impaired cognition preventing reliable feedback; recently irradiated tissue; actively bleeding tissue or untreated bleeding disorders; and the head or neck of anyone known to have seizures. Precautions requiring judgement rather than avoidance include pregnancy away from the abdomen and lumbar spine, epilepsy when treating below the neck, significant arterial disease, mild sensory changes, transdermal patches, and superficial metal such as jewellery. One correction worth knowing: deep metal implants are not an absolute contraindication for IFT — that convention derives from short-wave diathermy, and experimental work on titanium plates found no clinically significant heating from therapeutic currents.

Is interferential therapy painful?

It should not be. Most people experience a tingling, pulsing or prickling sensation under the electrodes, which many find pleasant, and sometimes a mild rhythmic muscle twitch if motor-level settings are used. Because IFT uses medium-frequency carrier currents, skin impedance is much lower than with low-frequency stimulation, so higher currents can be delivered comfortably — this is the modality’s main practical advantage. Intensity is titrated on your feedback to be “strong but comfortable”, never painful. Sharp, stinging or burning sensations indicate a problem such as poor electrode contact, inappropriate settings or an unsuitable electrode site, and you should say so immediately so treatment can be adjusted or stopped.

How is interferential therapy different from TENS?

Technically they differ considerably. IFT uses medium-frequency carrier currents of 2,000–4,000 Hz that interfere within the tissue to create a low-frequency beat, delivered through larger pads in bipolar or quadripolar arrangements, usually from a clinic machine. TENS delivers low-frequency pulses (roughly 1–150 Hz) directly through small adhesive electrodes from an inexpensive portable unit designed for home use. IFT is often described as more comfortable at higher intensities because of the lower skin impedance. In terms of results, however, a systematic review and meta-analysis of eight trials and 825 patients found both improved pain and function with no statistically significant difference between them. Given comparable outcomes, TENS has a practical advantage for ongoing symptom management since you can use it yourself at home. Both are named in NICE “do not offer” recommendations for osteoarthritis, low back pain and chronic primary pain.

Does CK Physio offer interferential therapy, and what will you recommend?

Yes, we have electrotherapy including interferential therapy on site at our Hanwell clinic — and we will tell you honestly whether it is appropriate for your condition. If you have osteoarthritis, low back pain or chronic primary pain, NICE advises against interferential therapy, so we will say so and use your appointment for assessment and active rehabilitation instead, which is what the evidence supports. If you are in the early weeks after knee surgery, where a double-blind trial found reduced pain, better range of movement and less swelling with IFT, we may offer it as an adjunct to your rehabilitation programme. Where a modality genuinely has strong evidence for your problem — such as shockwave therapy for calcific shoulder tendinopathy or plantar fasciitis — we will recommend that instead. Sessions are £65–£95, we are recognised by BUPA and AXA PPP, home visits are available in W5, W7 and W13, and you can book by calling 020 8566 4113. We are at 57 Elthorne Avenue, Hanwell, W7 2JY.

Sources: NICE NG226, Osteoarthritis in over 16s: diagnosis and management (recommendation 1.3.9); NICE NG59, Low back pain and sciatica in over 16s (recommendation 1.2.12); NICE NG193, Chronic pain (primary and secondary) in over 16s (recommendation 1.2.6); Rutjes et al., Cochrane review CD002823, transcutaneous electrostimulation for knee osteoarthritis; Kroeling et al., Cochrane review CD004251, electrotherapy for neck pain; Rampazo et al. (2022), analgesic effects of interferential current therapy; Almeida et al. (2018), systematic review and meta-analysis of TENS versus interferential current; Tugay & Kul (2023), randomised trial of IFC versus TENS versus sham in subacromial impingement; Jarit et al. (2003), double-blind placebo-controlled trial of home interferential current after knee surgery, Clinical Journal of Sport Medicine; Houghton et al., contraindications and precautions for electrophysical agents; Watson, Electrotherapy on the Web — interferential therapy; Almalty et al. (2024), effect of electrical stimulation on skin vulnerability to irritants; Thaler et al. (2017), heating of titanium implants by therapeutic electrical currents; Keramat et al. (2012), case report of an unusual effect of interferential therapy; Paley et al. (2021) and Vance et al. (2022), reviews of TENS efficacy and adverse-event reporting; NHS guide to waiting times in England. Where evidence is weak, mixed or absent — including IFT-specific mechanism of action, optimal parameters, bipolar versus quadripolar placement, and adverse-event incidence — this is stated in the text rather than presented as established fact.