Summary of main findings
The majority of orthopaedic trainees recognise that surgical procedures can be classified as a placebo but fewer realise that the placebo effect can be created unintentionally. Most find the use of placebo in clinical practice ethically acceptable. Deception and the associated damage to trust are the main concerns over the use of placebo. Most trainees believe the placebo effect has real and therapeutic effects, explained largely through psychological mechanisms. Considerably fewer would translate their beliefs into clinical practice. The main reason why trainees would consider using placebo would be to distinguish organic from non-organic symptoms or to manage pain.
In the context of research, the importance of protecting an individuals’ right to make informed choices and the need to minimise risk of harm are the most commonly expressed ethical concerns. The scientific validity of placebo is recognised and this equated with willingness to recruit patients.
Differences in results in comparison to other surveys
There is no generally accepted definition of placebo [
14,
16]. In our survey most respondents agreed with a definition of placebo as “beneficial treatment that is known to have no specific effect” and specifically accepted that surgical procedures can have a placebo effect. This is similar to the responses of senior orthopaedic surgeons [
15] but this is in contrast to the earlier study that observed that surgeons did not believe that surgical procedures could be regarded as placebo because they had a strong therapeutic effect [
14].
Physician’s personal expectations [
19] as well as positive consultations and suggestions can generate a placebo effect [
7] and this seems to be appreciated among physicians [
18]. In contrast, fewer orthopaedic trainees demonstrate understanding of these concepts. Only 41 % would include in a definition of placebo “therapies believed by the surgeon to be effective and specific even though, and unknown to the surgeon, they are in fact non-specific”. While the views of orthopaedic surgeons toward placebo are not as restrictive as those described before [
14] but it seems that they remain conservative relative to other specialities.
The respondents would recruit more willingly into studies with minimally-invasive, arthroscopic, procedures rather than into open surgery. Indeed, as the invasiveness of the placebo procedure increases, there is a corresponding fall in the proportion of trainees willing to recruit patients. When specifically asked about their concerns about placebo in research, the most widely held beliefs are that risks to the participant must be minimised and informed consent granted. The attitudes and concerns of surgeons may explain, at least to some degree, why the vast majority of existing placebo-controlled surgical trials investigated minimally-invasive procedures [
20]. It is important to note that some of the respondents in this survey appreciated the values of the three-arm design, i.e., of comparing two surgical procedures head to head as well as to a placebo intervention; however, they would still not recruit into such a trial.
Interestingly, in the context of clinical practice, trainees express a greater level of concern towards patient deception and subsequent damage to the doctor-patient relationship rather than potential side effects of placebo use. Trainees are aware of the need for informed consent and minimising harm so the obligations placed on them by the Declaration of Helsinki and medical regulatory bodies. Respondents’ opinions on other ethical issues, which are often a subject of a heated ethical debate, are divided.
The majority of our respondents believe that the placebo effect is real and that is has therapeutic benefits, which is similar to our previous survey of orthopaedic consultants [
15] as well as to previous studies which demonstrated that most doctors believe the placebo effect is real (68–95 %) and can produce a therapeutic benefit (68–96 %) [
16,
21,
22].
The circumstances in which placebos are used are complex. Among community physicians the most commonly reported reasons are to treat non-specific symptoms or to calm a patient [
18]. In the hospital settings, it is more often used to alleviate pain or anxiety [
16,
17] and as a tool to distinguish between organic and non-organic symptoms. [
17,
23] Orthopaedic consultants and trainees in the UK are most likely to use placebo as a diagnostic tool, as treatment for non-specific symptoms or when all the other therapies have been exhausted [
15]. The only significant difference is a greater use of placebo to control pain among trainees. It is surprising that both groups believe that only non-organic symptoms may possibly improve after placebo treatment.
Orthopaedic trainees commonly attribute the mechanism of the placebo effect to psychological factors. Our findings are similar to the previously reported beliefs among orthopaedic consultants as well as physicians [
15,
16]. Both cohorts recognise the role of psychological factors but underestimate the role of conditioning. However, only one in five respondents understands the importance of conditioning and the fact that the placebo response involves actual physiological changes. Confusion also exists over how the placebo effect differs from the natural history of a disease [
5] and between the true placebo effect, i.e., specific to the placebo manipulations, and the overall change in the placebo arm. None of the respondents suggested adding an observational, non-interventional group, to control for the natural history of disease. This is concerning as without an observational group it is not possible to separate a placebo response into the true placebo effect and non-specific effects [
4]. Furthermore, the absence of a observational arm results in no baseline from which to evaluate the harms and benefits of the surgical procedure [
20]. However, placebo-controlled surgical randomised controlled trials tend not to include an observational group [
20]. It is also concerning that over one third of trainees replied that the placebo effect is caused by unexplained phenomena.
Most doctors find the use of placebo in clinical practice acceptable but only a minority have no reservations. Permissibility depends on the type of placebo and the circumstances of its use [
13]. Evidence supporting placebo improves acceptability, with clinical research being a more powerful determinant than personal or departmental experiences alone [
15,
16]. Surgeons report using procedures with a possible placebo element less often than physicians [
13,
15]. This may be related to a more direct involvement in treatment [
24] or it may reflect the same phenomenon that was reported by Shapiro and Struening [
14], namely, that surgeons acknowledge existence of placebo effect but are unwilling to admit that some of the effect of surgical procedure may be associated with a placebo effect. It is interesting that, compared to senior surgeons, fewer trainees reported that they have never observed an operation with a placebo component [
15].
Strengths and limitations of this study
The participants were representative of the trainees in the UK. The responses were generated from all stages of training and the proportion of males to female (17.5 %) was also similar to the gender split among current trauma and orthopaedic registrars [
25].
The main limitation of this survey is that the response rate cannot be accurately calculated as it is not known how many trainees in the BOTA database actually received the invitation to participate. While a low response rate could be related to the delicate nature of the topic, the rate was smaller than in the other surveys (46–57 %) [
14,
19,
23] and lower than in the survey of senior orthopaedic surgeons (51 %) [
14]. It may be that trainees are less likely to participate in survey research, perhaps owing to time pressures or survey fatigue. Additionally, it should be noted that the survey of senior surgeons [
15] was distributed during a research conference, which might have primed participants to the importance of research and inflated response rates.