Hi Josephine,
Which booklet is that? I am of course concerned that there is such a warning. The only warnings I've come across are for active implants. As far as I know, the only concern for passive implants (as in knee or hip) is the heating factor, and TENS doesn't go deep enough to cause any problem.
Before I go into more detail, just the obvious point that if Sharon's pain is referred to areas some distance from her implant, then would you still have any concern about using a TENS? (I was using mine on my toe, by the way, but did use it several times on the adductors and ITB in the implant area.)
Here are a couple of samples of info (the first is obviously coming from a biased source, but still fits in with what I've always been led to believe about TENS machines).
This feels like a topic worth more exploration, since if TENS is ok to use the benefits can be huge, but if not . . . .
So, from this site:
https://www.tenscare.co.uk/index.php?action=qa#
Q: Is it safe to use TENS if I have a metal implant?
There is no reference in the medical literature to effects on implants other than pacemakers.
The signal from TENS only penetrates about 1cm below the surface and contains only a tiny amount of energy (just enough to persuade a nerve to send a signal), so we're pretty sure that there would be no ill effects caused by an implant focussing the current.
A Tenscare employee regularly used interferential therapy- designed to penetrate deep into the tissues - across his knee which has steel securing plates with no ill-effects.
Also from this site:
broken link removed: https://www.electrotherapy.org/FAQs.html
(The relevant paragraph is at the end, and I've put it in
bold
Electrotherapy with Metal Implants
Metal implants (pins, plates, wires, nails, screws and various arthroplasities - hip and knee most commonly) are widely considered to constitute a contraindication to most, if not all electrotherapy modalities - though in fact, this is not actually the case for many.
IMPORTANT : in the context of this section, only PASSIVE IMPLANTS are considered - any implanted device which is POWERED by a battery (or equivalent) is an ACTIVE IMPLANT and should be considered to be a real contraindication to many forms of electrotherapy.
The major concern is that the applied energy will result in 'significant' heating of the metallic implant, which would have a detrimental effect in the local tissues surrounding that implant, raising the tissue temperature to damaging levels. Whist that would almost certainly be true for some modalities (most especially the high frequency heating modalities - shortwave and microwave in particular), it is not true for many others.
The contraindications grid states that the modalities that generate significant heating in the tissues SHOULD NOT be applied when there are metal implants in the tissues (Shortwave, pulsed shortwave, microwave) and the other heating modalities should be applied with caution (e.g. hotpacks). The heat modalities with the least energy penetration into the tissues (infra red and wax) are not contraindicated by metal implants. (Interestingly, Draper et al recently demonstrated that relatively high powered pulsed shortwave treatments delivered to tissue in which there was a metal implant did not actually have a detrimental effect (Draper et al 2004).
Ultrasound, when used in a PULSED (non thermal) mode is acceptable over metal as a laser therapy when used at therapy doses. Electrical stimulation modalities (TENS, Interferential, NMES etc) are not contraindicated as the amount of energy applied is not sufficient to cause a detrimental heating effect in the tissues sourrounding the implant, though the presence of metal in the tissues will almost certainly distort the pathway taken by the applied current and may therefore generate some unexpected effects in terms of sensation experienced by the patient. Passive meatal implants are NOT therefore a contraindication to the electrical stimulation modalities (ACTIVE implants are though).
I'd very much appreciate any feedback you, Josephine, or anyone else has on this since I do use TENS with people who come to me for pain treatment (and on myself).
Best
Nick