We identified two overarching categories: “Making decisions about revision” and “Views about a randomised controlled trial” and a number of subthemes in each category. These two key categories and all subthemes within them are described in turn.
Making decisions about revision
A balance of patient and disease characteristics
Surgeons based their decision to perform either a one-stage or two-stage revision on a balance between a complex mix of patient physiology (patient’s age, condition of bone and surrounding soft tissue), co-morbidities, cemented or un-cemented primary fixation, the patient’s preference and social situation, and the characteristics of the infecting organism (for instance whether they could identify the infecting organism and its antibiotic sensitivities):
For infection, if I know the organism, then I might consider – or they’re elderly where they can’t really survive without a hip, then there are situations where I would go with a one-stage. But otherwise, the default position is two-stage. (Dave)
My default is still two-stage, but if the patient’s young, and they’ve got a cementless hip […] and the patient comes in and has got a short-lived infection, I would think more towards one-stage. So, so, generally, I would say, if it’s a cemented hip, it gets a two-stage. If it’s cementless, it gets a one-stage. But then there are various things that will make me, veer the other way. For instance, a diabetic, I would generally do in two stages. (Tim)
Although surgeons made decisions based on patient characteristics and the results of investigative tests and radiographs before surgery, this decision could be revised intraoperatively:
If I’m doing a single-stage revision for infection, I would still warn the patient that if I find something untoward intraoperatively then my default position would be a two-stage. (Dave)
Sometimes in theatre, you get in there and you know, with an infected hip, quite often the bone quality is very poor […] And I think if the bone is soft, again, I would rather do a two-stage, if I can. (Tim)
If patients required a two-stage revision a temporary spacer loaded with antibiotics may be fitted for a period of typically 3–6 months. Alternatively the surgeon may choose not to use a spacer during this period. One surgeon explained that he thought that a two-stage strategy increased the likelihood of eradicating the infection by 10% but saw this as a marginal gain when compared to the prolonged treatment period and reduction in quality of life for the patient:
There’s a benefit of having two because you get that slightly higher, you know, but it’s only, you know, a 10 in 100 or whatever. It’s a, you know, or whatever it’s, you know, 80 versus 90% - most people understand that difference. […] They know it’s a marginal gain for a big investment because it’s not just a second operation. The main problem is for 2 or 3 months, they’re gonna be incapacitated. To say they’re stuck at home, unable to work, unable to get out and about, dependent on other people for everything […]
That’s a long time isn’t it? Three months.
It is if you’ve only got a few years left to live, yeah. (James)
Patients’ social and personal circumstances were also taken into consideration:
So if the patient is the sort of patient who’s going to do well with a pseudarthrosis of some sort, are they going to struggle using crutches, have they got home circumstances, because that might push you more towards considering a one-stage, if all the other factors are involved […] you may consider doing a one, even though it may not be quite what you want because of the patient factors, to improve their quality of life. (Saul)
Surgeons reported that while some patients appear to be happy to follow their advice and rely on the surgeon’s decision, other patients had strong treatment preferences:
The other problem with doing a one-stage is trying to convince the patients because quite a lot of patients are coming along nowadays by the time they’ve come to see myself or any of the other consultants […] they have read up on infection and they know that there’s a higher incidence of recurrence in a single stage revision so very often they’re reluctant to have a single stage. (Duncan)
Patients could also elect not to have any further surgery if they felt they would prefer to go on long-term suppressive antibiotics:
After you’ve discussed the situation with the patient, discussed the potential for either a two-stage or a one-stage procedure, some patients elect not to go ahead. They’ve had enough of surgery. They may be elderly. They may be frail. They may simply want to go onto suppressive antibiotics, and accept the fact that the hip is not perfect. (Alex)
Surgeons also indicated that for older or frailer patients, the choice between surgery and long-term suppressive antibiotics was also determined by how the patient feels that their quality of life will be affected by the treatment.
The influence of infrastructure
The presence of physical and organisational structures and facilities needed to ensure operations can be performed are crucial. Surgeons suggested that deficits within the infrastructure could impact on treatment decisions. For instance, Duncan reported performing two-stage revisions because local microbiology services were unable to provide accurate service:
We didn’t until recently have the appropriate infrastructure in [our hospital] with regard to the microbiology department in order to be able to identify organisms accurately prior to surgery […] more often than not the aspirations would either come back negative or the laboratory would have some excuse as to why the sample hasn’t been tested properly […] Now over the last 2 years the microbiology department has changed and there’s a new set of individuals there who are more proactive and much more amenable to discussing matters with the clinician so it could well be that my view about [always doing two-stage] changes. (Duncan)
Costs to the NHS also played a role in treatment decisions. While the cost of performing a two-stage revision was considerably higher than a one-stage, it was seen to bring in more resources to the hospital:
Probably, the hospital gets paid more for doing a two-stage, right, which is always at the back of the surgeon’s mind […] the quality of patient care you can give, depends on your Trust not being in the red. So, you don’t want to do operations that lose your Trust money but your first priority is to get the best for the patient. Plus, when you’re in indecision, the fact that the two-stage operation doesn’t cost – that doesn’t, you know, it brings in more resources to the Trust, means you feel more relaxed about that option. (James)
At one hospital, the surgeons could not be sure that patients would have timely access to a bed for a second operation and so patients were kept in the hospital for the period between the first and second stage, increasing costs further:
When we start talking to hospital management they’re not very happy about two-stage procedures because it’s extra cost, extra time in hospital […] we usually do the second stage in about 8 to 10 weeks per surgery and we keep them in hospital for the whole period of time because we can’t guarantee that they will get readmitted at the specific time it was required. (Duncan)
Although it did not seem that economic costs influenced surgeons’ decisions, they nevertheless acknowledged some pressure to reduce costs. However a lack of access to adequate microbiology services presented a more direct concern and a barrier to the possibilities of performing one-stage operations.
Influence of literature, peers and training
Surgeons reported that they were influenced by published results of comparative studies of one- and two-stage revision surgery. They obtained this information at conferences and from scientific journals. Professional colleagues, particularly those more senior, also appeared to be influential:
[Consultant Q] himself is moving towards more one-stages and I think that’s sort of leaning more of us towards thinking about one-stages a, a bit more…and I think part of that is the results. […] We were all brought up, you know, 10 years, 15 years ago that two-stage is the gold standard and so on, but there’s more and more published results showing that one-stages are probably equivalent in terms of - in a lot of the cases in terms of microbiological clearance and so on, particularly if you’re careful that you pick the cases as we said, the more difficult ones. (Saul)
Otherwise everyone else has gone - pretty much gone for two-stage based on, I guess, the most published literature […] Although I, as you do as a registrar, I read all the one-stage papers – […] but they’ve certainly been pushed into the background compared to the two-stage papers, which have sort of dominated the literature for the longest period of time. So I end up doing two for most people. (Harrison)
Of the 12 surgeons interviewed, six surgeons from three different centres used a custom-made articulating spacer (CUMARS). This consists of the same implants that would be used for a definitive reconstruction but that the surgeon chooses to cement (or fix) in more loosely than they would normally for a definitive primary or revision hip replacement . Of the six surgeons who reported using this technique four suggested they used it almost exclusively (See Table 1).
Duncan reported that surgeons in the hospital where he worked had used a version of the CUMARS technique for around 15 years. However, although he used this method, most patients stayed in hospital for 8–10 weeks before receiving the second stage:
Yes we’ve been doing [the CUMARS] method for the last 15 years so it’s nothing new to us.
Right, so basically all your two-stage are loosely cemented, and would you say if patients are happy with the first stage you would leave it with them?
Well if they’re very elderly and infirm then yes we would. But that doesn’t happen often. (Duncan)
Tom explained that the CUMARS approach allowed him to modify how he fixed the spacer – which is an articulating ‘Exeter’ prosthesis – depending on his assessment of likely longer-term outcome; so a one-stage may remain as a one-stage in an older patient, whereas a younger patient may need a second revision later on:
So, if you were faced with an elderly patient who was very frail, you might try and do what is essentially a one-stage operation, using the spacer device to walk on and fix it as well as you could, and maybe that patient will never come to a second stage. A younger patient […] you might accept that it’s much more likely that you’re going to go to a second stage […] and so therefore, you would maybe not fix the hip quite so well and plan for a two-stage. So, it’s shades of grey rather than black and white situation and it’s a slightly odd approach too, the fixation of the implants. (Tom)
It appears that surgeons may use the CUMARS technique as it allows more flexibility in the longer term. This enables surgeons to leave open their options for further revisions, in the face of uncertainty about the definitive surgical solution and their uncertainty about certain patients’ outcomes.
Personal experiences of using CUMARS also prompted some surgeons to rethink their decisions about using one-stage or two-stage revision surgery:
It’s one’s personal experience with that, and seeing a reasonable number of people be happy with those spacers for a long time that, I guess will give you a bit of confidence to, just perform single-stage revisions. You know, if people are doing well after that procedure, you often wonder, ‘Well, if I had, just done things slightly differently, then they would have a better cemented implant, that is now likely to last an awful long time. And, why don’t I just stick with a single-stage, or tend to go more towards a second-stage?’ And that’s what I’ve tended to do, is drift in that direction. (Brian)
The surgeons who used CUMARS felt that it benefited patients, particularly outcomes such as pain and mobility. They also reported that use of an articulating implant avoided problems associated with cement spacers such as erosion of the acetabulum and pain:
The beauty of having a [CUMARS] is that essentially they’re happy, you know. They walk home. […] I’ve not had to feel sorry for a patient because they were struggling with pain because of something that I’ve put in. (Harrison)
Some of the cement spacers are, that are made, are designed to go in as articulating spacers up against the patient’s host acetabulum and those have got a terrible reputation for erosion on the acetabulum, pain, failure to allow patients to mobilise. (Tom)
Views about a randomised controlled trial
A lack of evidence for superiority
When asked which technique they used most often, all surgeons reported that they most frequently performed two-stage revisions, and they defined CUMARS as a two-stage method. Surgeons quoted published re-infection rates for each of the two methods and thought that the two-stage method provided ‘slightly’ better outcomes, particularly in terms of eradication of infection. However, surgeons also questioned this, and reported some uncertainty in the light of the absence of comparative evidence:
My bias would be that, if I just intuitively if you said, ‘What are you doing for this patient?’ I’d just go, ‘two-stage’ because that’s what I’ve always done. That’s what I’ve been taught. That’s what I’ve read about. And that’s what appears to be slightly better. But I realise that scientifically there’s no big comparative trial. (Harrison)
Well, I suppose the truth is, we do not know which technique, one or two-stage, is better. We know the two-stage probably has a slightly better chance of eradication of infection than one-stage by about 10%, so that is the reason to do it. (Steven)
A shift in practice
While some surgeons felt that two-stage revision provides a slightly better chance of eradicating infection, others suggested that over time they had seen increasing evidence that one-stage revisions were equally effective and that this would be the ideal way to treat PJI. Reasons for this included improved surgical techniques, increasing evidence for the effectiveness of one-stage revision and the influence of colleagues’ successful results when using one-stage revision.
I did feel more comfortable with a two-stage revision generally and always have done, but increasingly over the last couple of years I have thought more about doing one stages […] and one colleague in the unit has done probably more one stages than the rest of us and seeing that his patients seem to be doing well. (Saul)
Ideally the best way would be to do the operations as a single stage with a very low recurrence rate. (Duncan)
I’m getting an impression that there’s increasing evidence that it’s [one-stage] an equally successful way of eradicating the infection in an awful lot of people. That it’s as good. (Brian)
I’m up for change. And this study is quite timely, because I think there is a general shift, at a lot of the meetings that we go to, with some people doing more one-stages, I think, than they used to […] I think we’re getting better at our surgery. […] I think with OSCAR [ultrasonic cement removal], you’re more confident about getting your cement out. (Tim)
Those who talked about their change in attitude most often referred to increasing published evidence and the observed success rates of their colleagues as their main influence. We did not observe that years of experience or caseload had influenced a shift in willingness to consider more one-stage revisions amongst surgeons who spoke about this, compared to those who did not. However, we did not ask surgeons directly if they felt their years of practice or caseload had influenced their decision-making with regard to one and two-stage revision for infection.
A future trial and equipoise in principle
All surgeons felt that a future randomised controlled trial comparing one-stage with two-stage revision is needed.
At the moment what we’re doing is not randomising and unfortunately rationalising to say that ‘this’ is better than ‘this’, but there are no good studies. So we need the evidence. (Dave)
To conduct an ethical randomised trial, there must be clinical equipoise in place . Clinical equipoise is a state of uncertainty within the clinical community about the relative therapeutic merits of treatment options. Eligibility of a patient for a randomised trial depends on the existence of uncertainty about the best treatment option for that patient. When asked if they would be able to identify patients as eligible for randomisation in a trial comparing one-stage with two-stage revision surgery for infection, the majority were willing to put patients forward for randomisation when they were not convinced there was a best clear option, and where clinical equipoise existed.
So you’re quite happy to randomise patients if they’re suitable?
Yeah, but only obviously where I’m not convinced that there’s a clear best option. (James)
I’ve got a fairly open mind to that. […] Whilst in the majority of patients I guess I would be prepared to randomise them, there are, you know, occasional cases where you might feel that it’s not the right thing to do. (Brian)
How would you feel about randomising your patients into one type of surgery or another?
I’d, I’d be fairly happy about that, I think. I mean, if, er, unless there’s an obvious, you know, well, as long as there’s an opt-out in cases that you feel extremely strongly about, which there normally is [hmm] in these sorts of studies. (Howard)
I think it’s a good idea, but I think it’s actually very difficult, because, the patients are all so different [yeah], you know. It’s not just their, the infection. It’s the organism type they’ve got. It’s their age. It’s their comorbidities. It’s their ability to deal with a two-stage rather than a one-stage procedure. (Alex)
Some surgeons were asked what proportion of patients with PJI they would be happy to randomise to a trial comparing one-stage with two-stage revision surgery for infection. The majority of those asked, stated they would be happy to randomise most patients:
Right okay, what proportion of patients that you treat for infection each year would, would you be happy to randomise do you think?
All of them. (Duncan)
But in general, yes, I think I would be happy to randomise most of them. But yes, certainly, and the, the nasty gram-negatives, no, but otherwise most of them, yes. (Tim)
I think for, for a lot of the infections I would, I would be fairly happy to put most of them in, you know, a lot of them into that. Fortunately there aren’t huge numbers who fall into the really difficult bone or soft tissue category. (Saul)