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Summary: Placebo effects and surgery for overuse injuries

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  • Summary: Placebo effects and surgery for overuse injuries

    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.

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