Diagnostic Accuracy of the Ottawa Ankle Rules with Dr Chris Bleakley

In this episode with Dr Chris Bleakley, we discuss his Research Review of a recent article looking at the Ottawa Ankle Rules. We discuss the components of the Ottawa Ankle Rules and how they can be used in your clinical practice to help guide your treatments. We also discuss the clinical accuracy of the Ottawa ankle rules and what the findings of this systematic review were. 

👉 See Chris’s full Research Review here - https://physio.network/reviews-bleakley

Dr Chris Bleakley is a Chartered Physiotherapist and Senior Lecturer in the Ulster University. He is a leading academic physiotherapist and has published extensively in the field of ankle injuries. Chris enjoys teaching research methods to health science students, and he continues his clinical work at the RE:Play Physiotherapy Clinic in Belfast, Northern Ireland

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Our host is @James_Armstrong_Physio from Physio Network

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Transcript

SPEAKER_02 0:00

So I think that we've got pretty good data from these eight or nine thousand people to show that the rules really do what they were designed to and they can help to rule out injury pretty quickly within a room without specialist equipment.

SPEAKER_01 0:24

The Ottawa Anchor Rules can be a really useful clinical test to rule out bony ankle injuries after trauma. But how accurate are they? Well, in today's episode, we talked to Dr. Chris Bleakley, who has recently reviewed an interesting paper on the diagnostic accuracy of the Ottawa Anchor Rules for the Physio Network Research Reviews. And today we dive into some of the key findings and takeaways from it. To learn more about these research reviews and how they can make keeping up to date so much easier for you, click the link in the show notes now. Chris is a charter Thank you very much. Chris, welcome back to the podcast. It's great to have you back on. Thanks, James. Great to be here. Today, we're going to be chatting about a topic which you've recently covered in one of your great research reviews for the Physio Network, looking at the diagnostic accuracy of the Ottawa ankle rules. So we're going to dive straight into this and unpick the paper that you reviewed and come up with some real clinical pearls for the listeners today. So should we kick off with Ottawa ankle rules? Let's go with the basics.

SPEAKER_02 1:57

Well, they are kind of the de facto clinical test or algorithm that are used to try and rule out bony injury in people who present to emergency departments with an acute ankle injury or acute ankle sprain. And they've been around for a while now. I mean, they were first put together in early to mid 90s. And around that time, that was when there was the first empirical data to show that they were pretty reliable. They had good diagnostic accuracy. So they're essentially a clinical test and there are two stages to them. So if somebody comes in with an acute ankle injury, and they're complaining of pain in the malleolar or midfoot region, then there's an index of suspicion that they may have a bony injury. And as therapists, it's important that we make a decision as to whether or not this is a soft tissue injury or this is potentially a bony injury. So you follow that up with palpation. around the malleolar zone, so really the distal six centimetres of each malleolus, and then also palpate the navicular and the head of the fifth metatarsal. And if they have pain in any of those regions, then it merits getting a radiograph. And you also look at the patient's ability to weight bear. So if they can weight bear, and by weight bearing I mean they can take four steps, even if it's painful, then that's a negative test and they don't need an x-ray. So if they can't take four steps, either after the injury or in the waiting area, then again, radiography is merited. So they're pretty quick. I mean, that's a really strong component of the test themselves. They're fast. They don't require any fancy equipment and they can pretty much be done in any clinical room anywhere in the world.

SPEAKER_01 3:51

Yeah, really useful tool. But like with any tool, it's really good to see what research is behind them. And you brilliantly reviewed this research paper, Chris, which we're going to talk about today, which looks at the diagnostic accuracy of the ankle rules to exclude fractures in acute ankle injuries in adults, accentuating certain points here for our talk. And this is a systematic review and meta-analysis. So, Chris, can you Talk us through what the paper was about.

SPEAKER_02 4:18

Yeah, so this was a large systematic review and meta-analysis. And I guess for some of the clinicians or even graduates who maybe don't know what a meta-analysis is, it's where you take data from lots of different studies and you pull it together to look at the effect size. There were 15 studies that were included in this review. All of them had looked at the diagnostic accuracy of the Ottawa ankle rules. And the authors of the systematic review did a nice job. They used the PRISMA guidelines as a template to undertake their review. They pre-registered it. They looked at the study quality of the 15 studies. And they also then looked at the pooled data, essentially. There were data from over 9,000 or around 9,000 participants. So if you take all the separate studies and you pull that together. And it was diagnostic accuracy data from 9,000 people, which is, again, there are too many clinical tests out there where we have that breadth and that depth of data. I think the other positive was that it's data from lots of different countries. So this isn't just one emergency department sitting somewhere in the world. It was a variety of different emergency departments, which gives a little bit of external validity to the findings as well. So the data are generalizable across the board. Again, the review showed that whenever you pulled all this data together, the auto ankle rules have got a very high sensitivity, but quite a low specificity. In other words, they are good at ruling out ankle fractures and ruling out people who don't need to get an x-ray, which is positive because that's really what the auto ankle rules were designed for. They were designed to try and cut the number of unnecessary x-rays that were being undertaken in emergency departments. I think if you go back to pre-1990, before these rules came about, pretty much everyone who had an acute ankle injury were being x-rayed. And about 85% of those x-rays were negative. So when you think of the cumulative effect that that has across the world, and we know that ankle sprains or acute injuries are one of the most common that we see in emergency departments, that accumulates a lot of staff time and resources and wasted patient time as well. So I think that we've got pretty good data from these 8,000 or 9,000 people to show that the rules really do what they were designed to do. aid to and they can help to rule out injury pretty quickly within a room without specialist equipment.

SPEAKER_01 6:57

Brilliant, which is really useful because as you said earlier on, they're quick, they're easy and now we've seen from the systematic view of meta-analysis that actually they can be used with the mind of ruling out a bony injury. However, that specificity or the lack of thereof means that we're potentially going to get some false positives. Is that right?

SPEAKER_02 7:17

Yeah, we are. And I think that that's probably the lesser of two evils if you balance it up. I mean, the last thing that we want to do is to have a false negative, to tell somebody that they don't have a bony injury when they actually do. And I think the rules are set up to probably increase the number of false positives. And that's what boosts the sensitivity up. So yes, there will certainly be a percentage of people who will get x-rayed that will still be negative. But Again, when we look at the risks of each, it's much better with this type of tree-eye situation to have a higher number of false positives and a low number of false negatives that are in there. And we're certainly doing much better than we were in the early 90s when everyone who came into emergency departments were given an x-ray.

SPEAKER_00 8:05

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SPEAKER_01 8:28

So looking at this paper, Chris, what were the limitations of the review?

SPEAKER_02 8:32

There are always limitations. There was some heterogeneity in the findings. In other words, not all studies showed consistently the same effects. So some of the studies had sensitivities that were 90 plus. Others were a little bit lower than that. So there wasn't consistency there. There's a little bit of noise in the data. There was also probably more noise when you looked at the specificity In some of the studies, the specificity was as high as 60% or 0.6. In others, it was 0.1 or 10%. So there's a little bit of differences and sampling error. Normally, best practice, if that does occur within a review, is the author should go in and try and explain that. and try and see, well, why are there such differences across these studies? This isn't a criticism of the authors. They weren't able to do that. They weren't able to go in and examine the heterogeneity simply because there wasn't enough separate studies to do that. So normally what you would do is either a subgroup analysis to try and look and see maybe this is differences in the country, differences in the levels of experience of the practitioners that is driving this difference in the diagnostic accuracy. Sometimes they can into a meta regression and it's another way to do that. And explaining the heterogeneity is quite important because it might tell us in under what circumstances can we boost the diagnostic accuracy or boost the specificity, but they weren't really able to do that. They didn't have the numbers of the variety of studies. 15 studies wasn't enough to run any sort of meaningful subgroup analysis. So maybe in the future, when there's a couple more studies in this area, that they could do that. In terms of the general conduct of the review, it was solid. There were some differences in the included studies. Well, the vast majority were prospective in nature, which is what you want from these types of studies, that the data are generated and collected in real time. There were only a couple of them that were retrospective in nature. And I think it might have been nice if the authors had have taken those out of the analysis and looked to see whether or not that changed the pooled effect any, what would be a sensitivity analysis, but they didn't do that. So maybe if I'm being hypercritical, that could have been something that they would have done. But that, to be honest, doesn't really change the conclusion and the take-home message of this.

SPEAKER_01 10:51

You segued really nicely onto that take-home. So the clinical implications for this and how the listeners can take away something from this review, what would you say to that?

SPEAKER_02 11:03

Well, I think that 20, 30 years on, auto ankle rules are still a really useful and simple and cheap way to assess an acute injury. And bear in mind that they're not perfect. But if you apply the Ottawa rules, in addition to just good sound clinical judgment, so we never do these things in isolation, I should add that as a caveat. But if you apply those and they're negative, then there's a minuscule chance that you will have missed a meaningful fracture of the ankle. So they're a really good way to rule out bony injury and to reduce the necessity for radiographs within busy emergency departments. So I think they're still very relevant today. In fact, they're probably more relevant today. We know the pressures on EDs across the UK and Ireland certainly used to be just winter pressures. Now it's just pressures that's constant. We know that lots of ankle sprains still, people with ankle sprains or injuries still attend EDs. Anything that we can do to reduce the amount of time that people are spending EDs and the cost is useful. And I think that the auto anglers can really help with that.

SPEAKER_01 12:10

Brilliant. A really, really useful tool to have in the box, as it were. And a really useful review from yourself, Chris. I think the research view I knew when I read it was really succinct, really kind of highlighted what we need to know from the systematic review there. I think it's been a nice, succinct summary of what you found. So if you're interested in reading Chris's research review on the diagnostic accuracy of the Ottawa ankle rules and hundreds of reviews from other world-leading experts, then click in the link in the show notes below to try Physio Network's research reviews for free. Chris, thank you so much for your time. And I'm sure we're going to get you on the podcast again soon as well to talk all things ankles. Thanks very much.