View Full Version : Summary: Placebo effects and surgery for overuse injuries

07-09-2006, 11:08 AM
Dear all, thanks for your interesting feedback; here is a summary of the

Doug McClymont has provided an interesting case study that illustrates
the complexity of the decisions that surgeons have to make. He says that
he was an amateur guitar player in his younger days but he suffered from
carpel tunnel syndrome in both wrists and also from "trigger fingers"
flexed fingers that could not be straightened) in the middle and index
fingers of both hands.Initially he had surgery to release tendons in the
carpel tunnel on both wrists plus the release of finger flexors in the
palm of the right hand (his dominant hand) at the "metacarpel/carpel
joint" [sic]. The operation for carpel tunnel in both hands was
successful, as was the trigger finger release. Interestingly the
"trigger finger" problems on the other hand disappeared as well and he
is now playing guitar again! It would be interesting to know if that is
a common outcome or if Doug's outcome was just an isolated case.

Damien Bennett made an interesting comment about the difficulty of
getting approval for experiments on placebo effects. He pointed out that
whilst in theory a blinded placebo trial is the correct way of assessing
a new procedure, in practice is very difficult to pass it through an
ethics committee and justify it in terms of resource funding. He also
mentioned that research (Bennett et al, 2006) has shown that there is no
functional improvement when minimally invasive hip replacement surgery
is performed instead of standard surgery.

I meant to point out that rest could be a possible confounder; I did not
mean anyone to infer that it might be the sole cause of any placebo
effect. I mention this because one or two people made indignant
rejoinders to the effect that the placebo effect is solely due to the
patient's expectations; possibly I did not make it sufficiently clear
that I was merely questioning whether the traditional placebo effect is
the sole cause of cures in many cases. Incidentally, I forgot to
mention that Moseley et al (2002) concluded that the decisive factor was
the expectations of the doctor not those of the patient. Nobody is
accusing the doctors of a conscious bias, but at the end of the day it
is the doctors who write up the case histories not the patients. To
complicate matters still further, the beliefs of patients are probably
influenced by the expectations of their surgeons.

This suggests to me that we need to get more feedback from patients and
compare the outcomes of all of the available therapies. On the subject
of case histories, I might point out the famous case of George Bernard
Shaw's hydrocele (as described by Hesketh Pearson his friend and
biographer). A health practitioner called Roche allegedly cured Shaw's
hydrocele; his main strategy was apparently to spoon sugar onto the
patient's tongue. Although this tale is legendary it probably did not
get a mention in any medical journals of the time. If there are budding
historians out there it might be interesting to see if Roche ever got a

My literature search turned up one study that provides food for thought.
Dr Leigh Riby (a Psychology lecturer of Glasgow Caledonian University)
has found that an area of the brain known as the the hippocampus lights
up with activity in after a glucose-sweetened drink (Riby et al, 2004).
Many studies of the placebo effect stress the need to use one of the
so-called inert placebos and this term is colloquially known as the
"sugar pill". Ironically if they have used glucose pills as placebos
they have really been using they might in fact being using a substance
with powerful pharmacological effects on elderly patients (and one that
might have strong effects on strong and chronically ill patients).


David McFarlane
WorkCover Authority of New South Wales


1. Bennett D, Ogonda L, Elliott D, Humphreys L, and Beverland D., 2006,
"Comparison of gait kinematics in patients receiving minimally invasive
and traditional hip replacement surgery: a prospective blinded study",
Gait Posture. 2006 Apr; 23 (3):374-82. Epub 2005 Jun 24.

2. J. Moseley, K. O'Malley, N. Petersen, T. Menke, B. Brody, D.
Kuykendall, J. Hollingsworth, C. Ashton and N. Wray, (2002), "A
Controlled Trial of Arthroscopic Surgery for Osteoarthritis of the
Knee", New England Journal of Medicine, July 11, 2002, Volume 347:81-88,
Number 2.

3. Riby L, Meikle A, Glover C., (2004), "The effects of age, glucose
ingestion and gluco-regulatory control on episodic memory", Age Ageing.
2004 Sep; 33 (5):483-7.

Any recommendation concerning the use or representation of a particular
brand of product in this document or any mention of them whatsoever
(whether this appears in the text, illustrations, photographs or in any
other form) is not to be taken to imply that WorkCover NSW approves or
endorses the product or the brand.

************************************************** ************************************************** ************************************

This message, including any attached files, is intended solely for the addressee named and may contain confidential
information. If you are not the intended recipient, please delete it and notify the sender. Any views expressed in this
message are those of the individual sender and are not necessarily the views of WorkCover NSW.

************************************************** ************************************************** ************************************