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Hip and knee replacements -

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Norman Swan: Hello and welcome from me, Norman Swan. A bare bones Health Report for you today.

Hip and knee replacements; why are some Australians unhappier with their new joints than others? Spine surgery and workers' comp; a toxic mix. Back pain and spinal injections made up by a compounding pharmacy; an even more toxic mix. And when do you need to worry that you might have broken a bone in your neck?

Let's start with hip and knee replacements. Each year, Australian orthopaedic surgeons replace over 35,000 hips and over 23,000 knees and both the numbers and rates of these procedures are rising inexorably.

The majority are done in the private sector, yet a study at the University of NSW suggests private patients are less happy than public ones after the procedure. It also seems that Aussies as a whole are less happy internationally.

Ian Harris is Professor of Orthopaedic Surgery at the University of NSW.

Ian Harris: This stemmed out of a study which compared the satisfaction with the knee replacement surgery between different countries. So they compared Australia to the UK to the US. And while satisfaction is still fairly good after joint replacement, they found that there was a difference between the Australian patients and the UK and US patients.

Norman Swan: What sort of questions were they asking?

Ian Harris: They were asking satisfaction with the outcome, but interestingly they were also asking expectations, and that's where the difference lay because more than a half of the Australian patients that were involved in this study expected to have no pain with recreational activities, be able to walk more than three kilometres unaided without pain. So basically more than half of the Australian patients...

Norman Swan: So the Australians thought they were going to get a bionic knee!

Ian Harris: Yes, they thought they'd be normal. Their expectations were significantly higher than in the other countries, and consequently their satisfaction was a little bit less, and their willingness to undergo the procedure again...that's another question that is often asked in joint replacement surgery, they say given your time over again, knowing what you know now, would you have had the procedure or would you have the procedure again? And in that particular study they found that 25% of the Australians said that they would not have the procedure again. When you look into it, that is not a very out-there figure. Figures of around 20% are fairly consistent for knee replacement. And there is a difference between knee replacements and hip replacements. Consistently hip replacements score better than knees.

Norman Swan: Why is that?

Ian Harris: Mechanically it's a completely different joint and it's fairly easy to restore a very good range of motion in the joint, and it's basically a ball and socket joint. It's pretty simple. In the knee it is several joints, it's the kneecap joint as well as the main joint. The mechanics of the knee joint, it's not a pure...

Norman Swan: It's not a straightforward hinge?

Ian Harris: It's not a straightforward hinge, yes. The range of motion after a knee replacement is not normal, it's not close to normal, it's not meant to be, and these are some of the things that limit knee replacement I think.

Norman Swan: When they looked at the functional outcomes comparing nations, were they any different?

Ian Harris: No, I think they were pretty close, which is interesting.

Norman Swan: So the results were as good wherever you got them done by a competent surgeon, it was just you got a bit pissed off if you were led to expect or somehow expected to have a better result than you did.

Ian Harris: Exactly.

Norman Swan: And did you look at it in the knee study why they had those expectations? Do we have more bouncy, optimistic orthopaedic surgeons than the British?

Ian Harris: No, this is where our study comes in, this is hips and knees, this study. We've mixed them together but we did analyse them separately, and we looked at patient versus surgeon satisfaction, which is reported in another study, because it's my feeling and we found that surgeons tend to be more satisfied with the results of the surgery than the patients are...

Norman Swan: [Laughs] What a surprise! 'I did such a wonderful job.'

Ian Harris: Yes. So we looked at that. We've looked at it in fractures as well, I don't want to pick on joint replacement surgeons, but the same thing with a leg fracture, with a tibia fracture, the surgeons are more satisfied than the patients...

Norman Swan: So let me just get this straight, so in other words you're not finding out from the patient whether they were satisfied with their surgeon or not, you are just comparing the satisfaction rates of patients and surgeons.

Ian Harris: Yes, the question is how satisfied are you with the surgery, not with the surgeon.

Norman Swan: Right, and you asked both the surgeon and the patient.

Ian Harris: Yes, we asked them exactly the same questions.

Norman Swan: Public and private sectors?

Ian Harris: Yes, this one we divided them up between public and private. We had four hospitals, two public, two private, and both neighbouring hospitals with the same surgeons at each group of two hospitals, and they are all experienced joint replacement surgeons. It depends on how you look at it. By and large the results are very good, private and public. There is a big improvement in function, and there are fairly high satisfaction rates of about 90%. But the difference we found echoed what we thought before which was that private patients tend to have higher expectations, and it's their higher expectations really that let them down, it is not the function of their knee. The function of their knee is just as good as I would expect, but perhaps it's not as good as they would expect.

Norman Swan: So there's no difference regardless of whether you got operated on by the same surgeon, but the difference was you were more likely to be disappointed in the private sector as a private patient.

Ian Harris: Yes.

Norman Swan: And have you looked at why...again, getting down to this it surgeon related, that the surgeon is just bouncy and ebullient and optimistic?

Ian Harris: We were unable to find a difference between surgeons in the different surgeons that we looked at. So we didn’t find that one surgeon was particularly more enthusiastic than the other. And I'm not convinced that surgeons give public and private patients a different picture. It may be that the private patients walk into the rooms with a different expectation.

Norman Swan: So what's important then is that the orthopaedic surgeon knows that and sets expectations differently.

Ian Harris: Exactly, yes, and this is my point with all of this kind of research that I do, is that surgeons tend to base their recommendations on what they believe the result will be, and yet I think that surgeons do tend to overestimate the benefit that the patient will receive. So surgeons just need to adjust their own expectations and they need to make sure that the patients are well aware of the realistic expectations. They may have some pain in the knee, they will not be able to walk fast for long distances.

Norman Swan: There has been a lot of discussion in medicine as a whole about the patient narrative, in other words getting behind the patient's story and really asking about the lived experience of the patient. So it's not just in surgery, it is in psychiatry, mental health, psychologists, cancer care, right through there's a criticism that we don't actually ask people about their own experiences and their own desires and goals. Is that the issue here, that at six-week follow-up or12-week follow-up they ask fairly mechanical questions rather than about people's lives?

Ian Harris: I think that used to be the case and I think that's changed a lot. So when I was training, the outcome of surgery was whether it needed further surgery, revision surgery, what the range of motion in the knee was...

Norman Swan: Was there any pain...

Ian Harris: Yes. Now we really base all of our outcomes on patient-based outcome scores. Again, we're asking them set questions, but those questionnaires that we use are highly correlated to health-related quality of life, those kinds of things.

Norman Swan: And what sort of questions do you think people should be asking themselves as consumers before they go into joint replacement surgery? Presumably it's around what your personal goals are, what you want to achieve by this?

Ian Harris: Yes, that's right, a patient should make a list of what they want to get out of it. Because, for instance, a patient who loves golf and wants to walk 18 holes of golf and can only walk nine, that's a big deal to them. It's not a big deal to me, but that's a big deal to that particular patient. That's the kind of question that patients should be asking; will I be able to play golf, a full 18 holes, with this joint replacement? If the answer is yes then they should go ahead, but...

Norman Swan: And are you able to predict that for, say, somebody with osteoarthritis of the knee who is going to have a knee replacement?

Ian Harris: Yes, I think you can. You're going to improve their walking distance, you're going to decrease their pain level, and certainly that's only a marginal improvement. Somebody who can walk nine holes and wants to walk 18, that's an easy game. The problem is when you get the patient who says, well, I do barefoot waterskiing and my times are down, that patient is not going to do well with a joint replacement.

Norman Swan: And finally, before we go on to the spinal surgery part of the story here, you're one of the enthusiasts for the National Joint Replacement Registry in Australia which is a world leading registry which compares devices, actually what the surgeons put in. And it has shown variation, particularly in knees, but also in hips as well. Were there enough patients in the study when you are looking at satisfaction to relate it to the actual device that was in? Because the Replacement Registry is rather crude; do you need a revision of your joint or not?

Ian Harris: Yes, that's right, the joint registry looks at procedures and repeat procedures, as you say. The difference between prostheses is subtle, it's very small. There are dozens of prostheses out there. Occasionally some are flagged that are underperforming...

Norman Swan: Meaning that they need to be replaced more often?

Ian Harris: That's right, yes. But in this study we did not look at the prostheses because the difference between 95% of the prostheses on the shelf is so subtle that you wouldn't pick up a big difference in a patient-based outcome score.

Norman Swan: So in this day and age with a knee replacement, how long does an artificial knee joint last?

Ian Harris: They last a long time. If you look at the Joint Registry, which I don't have in front of me, but you're looking at figures of around 95% lasting five, 10, up to 15 years at least. So that's by far the majority of them will last more than 10 years.

Norman Swan: But that's a lot less than hips.

Ian Harris: I think the revision rate is a little higher for knees. Again, I don't have those numbers in front of me. I do know that the functional results, you know, how the patient goes, is consistently better for hip replacements than knee replacements

Norman Swan: Ian Harris, who's Professor of Orthopaedic Surgery at the University of NSW.