Professor Andrew Price

Brief Outline:

Professor Andrew Price is a consultant knee surgeon.

Background:

Professor Andrew Price is a Consultant Orthopaedic Surgeon at the Nuffield Orthopaedic Centre NHS Trust and Professor of Musculoskeletal Science at the Nuffield Department of Orthopaedic Surgery, Oxford University.

More about me...

Professor Andrew Price’s clinical work as a consultant knee surgeon is based at the Nuffield Orthopaedic Centre in Oxford. He also leads the Knee Research Group in the Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences at the Botnar Centre, and he is a Fellow of Worcester College at the University of Oxford. 

Professor Andrew Price studied medicine at the University of Cambridge before completing his clinical studies at St.Thomas' Hospital in London. He studied for a PhD as a postgraduate student at the University of Oxford, completed his Orthopaedic surgical training based at the Nuffield Orthopaedic Centre.

Professor Andrew Price is a member of the British Orthopaedic Association, the UK National Joint Registry Steering Committee, and past President of the British Association for Surgery of the Knee (BASK).

Professor Andrew Price explains about some of the causes and contributing factors for osteoarthritis.

Osteoarthritis is a very common condition that affects many people. It's age related. So it's more commonly seen in people, say, over the age of 50. And that is because it's a condition which is related to your genetics. So you have a predisposition to it. But you can also develop it without any sense of genetic predisposition.

So it's very common. It's a condition which is characterised by certain features within the joints, which produces a clinical pattern of symptoms which really relate to pain, stiffness, swelling and therefore loss of function. So loss of ability to walk around easily, do activities of daily living. And there are a number of factors which contribute to that.

Some of them we know a lot of information about. So, for instance, we know that age is related to the development of osteoarthritis. We also know that weight is associated to the development, and contributes to, the kind of process of it deteriorating.

We also know that there are certain other things that can happen to a person which may affect your ability to develop arthritis. So if you have injury to the joint, if you damage the meniscus – these are the sports cartilages inside the knee - or some of the important ligaments in the knee, that can predispose you to developing osteoarthritis. If you have had a previous fracture, that can predispose you to developing osteoarthritis. And there are other conditions which, in certain circumstances, may end up with you developing an osteoarthritic pictures. So you may have-, you may previously have had an inflammatory arthroplasty. And then later in your life, if that settled down, you may subsequently develop osteoarthritis. So there's an interplay between some of the other arthritis problems in osteoarthritis.

The severity of the disease I think you could consider that in two ways. The severity of the disease that I think is probably most important to patients is how painful and how disabling the condition is. So there's something about osteoarthritis, which is unusual, is that the amount of damage that you see within the joint, say, on an X ray or an MRI scan, doesn't always correlate to how bad the symptoms are. So you can have a patient who has a very damaged disease process, a very damaged knee with loss of cartilage, new bony growth and deformity. And it's sort of easy to understand that that patient might have very severe symptoms.

At the same time, you can have a patient whose developing osteoarthritis at the earlier stages of the disease who can also have very severe symptoms. But their structural damage, you would describe as not being as severe, ao it's earlier in the process. But I think if I were to kind of to sort of summarise the key bit, the severity relates to your symptoms. So if you are very disabled through pain, swelling, that is a severe osteoarthritic picture.

It's interesting to think if there are any other things which are associated with its development, and we know that weight is associated with the progression of arthritis. So if you're above your ideal body weight then there's a higher risk that your symptoms will progress and the structural damage will progress.

Interestingly, there isn't any specific data or research which supports specific foods being related to a risk of developing or progressing osteoarthritis. There are lots of speculative work around that, but nothing where there's hard evidence to suggest that it's related to anything specifically the we eat. So the issue around weight is a more general thing that is a very important factor in managing osteoarthritis.

 

Professor Andrew Price explains about the pathways and referrals to knee specialists.

So this is a very interesting question. I think there's been a lot of change and there is quite a lot of variability across regions as to how this works, but I'll give you a broad outline of the referral pattern.

It still remains that the primary point of contact for a musculoskeletal problem is a general practitioner (GP), who would be able to assess, offer simple advice in managing osteoarthritis, but can also pick up if there's a very severe almost acute problem that needs something very rapidly done to it, the GP can intervene. But the general practitioner, in that first point of contact, will be sharing information, typically giving advice around exercise, weight management and referring to physiotherapy as a first- a sort of port of call to help in the management, because exercise and physiotherapy is a key part of managing this condition.

At that point, a patient may get referred through to what's called an intermediate care pathway. So there are groups of medical practitioners who work with GPs to manage musculoskeletal conditions. So they're assessed, and physiotherapy and non-operative - essentially non operative measures for managing osteoarthritis - can be kind of choreographed and organised by the intermediate care providers.

Essentially I think you could summarise that group of very experienced people who are good at managing these conditions, it's based around physiotherapy and based around assessing your initial response to these sorts of simple measures.

Now osteoarthritis has a habit of presenting with symptoms that come and go, particularly in the early stages of this disease and even in the most severe stages of this disease. So the non-operative approach with good information is really important; the self-management effectively but supported by these services. If over a slightly more prolonged period of time, the symptoms are severe and intrusive then a patient would be referred through to secondary care or a hospital. That's what you might describe that part of the pathway.

That referral in some regions does come directly from the GP, but in other regions will come from intermediate care or what people call musculoskeletal hubs, where you're referred to a hub, they assess you, you have physiotherapy and if you don't settle, you'll be referred through to secondary care. And in a secondary care setting, you'll be seen in a clinic by a hospital consultant. And I think a way to think about that is if you're approaching the stage where surgery may be a good option for you in managing your disease, managing the osteoarthritis, then you'll end up in secondary care.

I think it's important to understand that the vast majority of patients with osteoarthritis still sit in primary or intermediate care, with their symptoms managed non-operatively with good advice and support with exercise and weight loss and physiotherapy. It can also be augmented with injections into the knee and there are some other simple measures that can be done.

About 10% of the population of people who have osteoarthritis might end up having an operation. And that is the-, about 1 in 10, so the vast majority of people are managed non-operatively. But if things progress then you go to secondary care through these different pathways and it's assessment around surgery.

So pathways are really sort of quite well defined now. So if you were referred from primary or GP through intermediate care and you end up in secondary care, it's highly likely that the secondary care consultant that you see will be specialised in treating the osteoarthritis in a specific joint, commonly hip and knee go together. But those consultants are specialists in managing knee and/or hip arthritis.

It's a different problem if you have shoulder or elbow or hand osteoarthritis. So it starts to become quite tailored down to your specific problem. So I'm an example of a knee specialist. So if you came to see me in secondary care, I would be dealing with your knee osteoarthritis. And I think that's the way to look at it, there isn't a general consultant you would see; the system from GP to intermediate care is refining that down. So by the time you come to secondary care, you'll see a specialist in your specific problem.

Professor Andrew Price explains the risks and plan for those taking blood thinning medication before surgery.

Anybody who's having a joint replacement, there's a period of pre-assessment where your individual circumstances are looked at very closely by the secondary care or the hospital. So you're under the care of a consultant but the pre-assessment team will look at you and assess aspects of your health not directly related to your knee arthritis which need to be addressed.

Now one of these is whether patients takes medication to thin the blood, or clotting medication as it's kind of referred to. And some examples of that would be patients who've had a previous blood clot in the leg or deep vein thrombosis or pulmonary embolism. Those patients may be on long term medication to thin the blood.

Similarly, patients who've had a problem with their heart and, say, who've had stents. So these are small cardiac operations to allow better blood flow to the heart. And people who have stents are protected with blood thinning medication.

So let's assume that, say, there's a, there's quite a proportion of-, there's quite a big proportion of people who are being pre-assessed who are going to have a knee replacement, say, who are on blood thinning medication. So the risk, if you stay on your blood thinning medication, is that at the time of your surgery, you would bleed in a way that would be dangerous for you. So in the pre-assessment process, there's some very specific planning for the individual about stopping the blood thinning medication and replacing it with other medications after the surgery to reduce the risk that we're balancing. So there's the balance of you being someone who is going to clot versus someone who's going to bleed too much. So we assess you, stop your blood thinning medication, put you on to other treatments while you're in hospital, and then restart your blood thinning medication in a few days after, usually a few days after, the operation.

During that time, there are some very specific things that happen. Each patient has a specific assessment just before your surgery to make sure that we've got this plan correct and it's tailored to your own needs. And postoperatively again, at the time you're discharged back to your home or wherever you're going, that there'll be a specific plan for how to restart your blood thinning medication so that there's no confusion about how that works.

Of course there are risks involved in surgery. So even with these plans, some people have blood clots and some people will bleed. Hopefully we're trying to minimise both of those issues. And in my experience, they are actually managed to a very acceptable risk compared to say how things were 10, 20 years ago.

So it's all about patient focused care: stop your blood thinning medication, use an alternative treatment while you're having your surgery, and then restart as an appropriate time making sure the patient really understands how to do that, and that your general practitioner is aware so that they can always step in and help.

Professor Andrew Price discusses the issues for people who can’t clot their blood and have clotting disorders.

So this is a much less common situation, but there are people who have problems with clotting their blood. And clotting their blood is a- is the body's normal response to try and help control bleeding. And if you suffer from haemophilia, that's a very severe condition where you have problem making blood clots and you can bleed. And there are some much milder versions of that type of problem.

Now, there's much more known about these conditions than, say, there used to be, and the ways of managing them are much, in my view, much better developed. But if you have a severe bleeding disorder and you are at risk of bleeding, you will probably already be on some form of medication or have a treatment plan around how-, your haematologist or blood doctors are protecting you from having a problem with not being able to clot.

Now, of course when you come into hospital, there's the balance here between understanding that with surgery there's a risk of bleeding and there's a risk of you producing a clot after the operation. And we will look at each individual and work with your blood doctors very specifically in these type of situations about making a plan about how to manage you. And that plan is about avoiding the risk of bleeding and protecting you from blood clot. And I think, most importantly, making sure the patient understands what the rationale and the reasons why we're making these choices.

It's a much rarer problem. But again, it's all part of if you think of the issues of surgery and blood clotting and bleeding as two things that you're weighing up in every circumstance, an individual plan could be made for each person going through this process.

Professor Andrew Price describes what is usually discussed at the referral appointment.

So now we're talking about the process that's happening in secondary care. So, at the hospital where you're meeting a consultant who's a knee or hip specialist as an example. So if you're coming to see me, I'm a knee specialist. In this sort of situation, you've had severe arthritis which is starting to really impinge on your life. Typically, with pain, stiffness. And when you come to secondary care, there's a discussion about what other options are there available to treat your osteoarthritis. And there's no doubt that that really what's coming into play is surgery as an option. But it does still need to be seen in the context of it is one option and continued non-operative management is still really important in how you manage this. And some people may still choose to not have an operation when they've considered the risks and benefits.

So we know a good way of thinking about this is we talk about a shared decision-making process. So this is the consultant or specialist working with the patient. And I think it's always good if other relatives or people, someone's partner, is involved in the process where you discuss what would be the benefits of having a knee replacement and what are the risks. And that balance, once you're informed of those risks and the proposed benefits, the patient can try to take a moment, get the context of their own life and make a decision about whether they want to think about having a knee replacement or not.

And to kind of summarise that you would say that the reason why you would have a knee replacement would be to try and improve your quality of life by focusing on a reduction in pain and improved mobility, and that improved mobility returns you to things you like doing and your quality of life improves. And for many people, they feel brighter in themselves and they can return to a healthier lifestyle because they're active again. Now there are-, that's the positive.

Then there are the things you need to consider, so the risks. And I would categorise the risks in three ways.

The first risk is the risk that the operation doesn't achieve the things that you want it to achieve, so that your pain and your mobility don't improve in the way you would like them to. And, say, a knee replacement, somewhere around 15% of patients will have some degree of problem after the operation where they won't have all of the improvement they want and they may have ongoing problems. And for a small percentage of people, they may regret having had the operation. However, the vast majority of patients will find that they get this large improvement in their pain and stiffness, and they're very happy with the outcome - but they need to understand the risk that not everybody finds that their operation turns out like that. So there's the risk of not achieving what everybody's set out to achieve.

Secondly, there are medical complications. Now, we've already discussed blood clot and bleeding, and I would add in infection as a really big issue that you need to understand. Because if you get an infection into a knee replacement, it's a really big issue and you're going to need further surgery and it's not something that anybody wants. But we protect you from infection and we protect you from blood clot and bleeding, and what this does is reduce the risks to what we what we think is an acceptable level. And we talk about risks which they are occurring in less than 1 in 100 patients. Actually, a serious blood clot will occur in around 1 in 1000 patients. And some of the infection occurs perhaps in 1 or 200 patients. So these risks, you need to understand them, you need to understand the consequences of them, and you factor them into the shared decision-making process. In addition, there are other medical complications. So a small, heart attack or a problem with the blood supply to your heart, or small or mini stroke can occur. Now these things are critical medical problems that affect people who have knee replacement that, again, they don't happen very often, around 1 or 200. But you need to understand that risk and balance it against the problems you're having with the knee osteoarthritis.

The final risk to consider is the risk that over time further surgery is required to manage the joint replacement if it starts to perform poorly. So that can happen in the early stages after the operation; if there's a problem with instability, we've already mentioned infection. And it can happen in the later stages if the components of the knee replacement start to wear out. So it's important to understand that a knee replacement as a-, for some people, has a life which won't sort of go on forever. And we talk about revision surgery or the sense that you have to have the operation redone. And that happens, we talk about 1% of, knee replacements having to be revised per year. And a rough rule of thumb is by 10 years after the operation, 10% have been revised but 90% is still functioning well. And by 20 years after the operation, 20% have been revised and 80% are still functioning very well. So that gives you this context of how long the thing will last. It's important because if you're a younger patient then your risk of having to have further surgery is somewhat higher. So joint replacement, say, under the age of 55 leads to a higher revision rate. And that's something you really need to critically think about in the shared decision-making process.

So trying to bring that all together, you think about the benefits which are reduction in pain, improves mobility, increased quality of life; the risk that you don't achieve that; the risk that there could be medical problems, infection, blood clot, mini stroke; and the risk that you might need another operation as time goes by.

Professor Andrew Price explains the differences in outcomes for partial knee replacement and total knee replacement.

So the biggest decision in someone thinking about having surgery is whether or not you would have a knee replacement; that, there's no doubt, that is the biggest decision to have.

If you're a candidate to have knee replacement, there are different ways of performing that operation. And perhaps the biggest thing to think about is whether this would be partial or total knee replacement. And that they're both very good operations and they both-, a lot of these procedures are done, say, in the UK for treating osteoarthritis and around the world, there's no doubt that more people have total knee replacement than partial knee replacement. But partial knee replacement is being done more commonly.

And the thing to consider is if there are patients who are candidates who could have partial or total knee replacements; there are some patients whose osteoarthritis damage is at the more severe end of the spectrum where they're not a candidate to have a partial knee replacement. But if you are someone who has arthritis which is localised, say, to one compartment, there is now a choice: partial or total knee replacement. And again, as part of your shared decision-making process, you need to understand the benefits and risks of both of those procedures.

And if I might kind of summarise that for you: partial knee replacement in some respects could be thought of as a slightly smaller and less invasive procedure. And some of the advantages of that are a faster recovery in the, say, first six weeks after surgery. In the first 4 or 5 years after the operation, you're perhaps more likely to be at the top end of the functional outcome group. So partial knee replacements do a little better - or some of the partial knee replacements do a little better. And there is a reduced risk of complications. So the risk of infection, blood clot, problem with your heart, problems, say, with your kidneys after the operation is reduced with partial knee replacement. So there's the good things stacking up.

The thing to weigh against that is that if you look in the, data or the evidence across the country, you will see that partial knee replacements have a slightly higher chance of being revised. Now, it's important to understand that if you are going to consider partial knee replacement, you would want that being done by someone who is experienced in partial knee replacement and is able to do that. So you talk with your surgeon about that. If they can't do partial knee replacement and you're a candidate for it, they should refer you to see someone who does do partial replacement. But as long as the operation is being done well and we're optimising the ability of the partial knee replacement not to be revised, then it's a pretty good option. But you're balancing slightly faster recovery, slightly higher function, slightly reduced risk profile against a slightly higher revision rate. And you've got to make that balance. So, a slightly higher reoperation rate and you've got to make that balance. And that's the summary of kind of partial or total knee replacement.

But I go back to where I came into this point. The big decision is whether you would have a knee replacement or not. That I think is the key decision and then partial or total plays into that.

Professor Andrew Price explains what a patient can expect to happen on the day of their knee replacement surgery and why some people have day surgery.

If we think about what happens to a patient when they go to have a knee replacement, I would say across the country it's a very similar pattern wherever you go in terms of what's going to happen. There will be subtle differences, but what I'm about to describe is fairly universal in terms of what you expect to see.

So I think it's always-, the patient’s always surprised how early you have to turn up to the hospital on the day of surgery. That doesn't happen in every hospital because some people will be- they'll stage it and you might have to come, say, in the morning or at lunchtime. But most people have to turn up fairly early. And what happens is when you turn up at hospital, there's a whole bunch of checks and assessments and getting you ready for the surgery that are required. So a nursing team sees you to settle you in on the ward to make sure that nothing untoward is going on. Take some observations about your blood pressure and pulse, and just make sure that we're in good shape to move forward.

You're seen by an anaesthetist who'll talk to you about the techniques involved in having surgery. You will almost certainly have had information about this at the pre-assessment visit. So none of this is particularly new to you. But the detailed decision making about the type of techniques that the anaesthetists will be using will be discussed and finalised at that point.

The patient will also see the surgeon. The surgeon will make sure that everybody's happy with the decision to have the operation, that you've importantly marked the side, I think patients always find that amusing that we've put a big mark on one side or the other but t's critically important to do that. So we make sure that everybody knows what we're going to do. So you mark up your knee and make sure that the consent process has been finalised. You may have signed a consent form before you come into hospital, or you may sign it on the day, but that consent process is finalised.

Okay, now we're good to go. So at some point during the day when you will have been scheduled, you will move from the ward to the operating theatre. You'll meet the anaesthetist who will undertake the procedures that have been planned. You will go to sleep, which is either a general anaesthetic or a very deep sleep where we sedate you if we're using, say, spinal technique and you'll be taken into the operating theatre. A series of checks are in place very much like, say, you'll be aware-, you'll think about pilots flying a plane where they check that everything is okay before they set off. Exactly the same thing happens before surgery. We check all the things are in place. We check that you've had your medication to stop infection. We check you've had your medication to stop clotting, if that's what we're doing. And then the surgery begins.

Surgery for knee replacement typically takes an hour. Sometimes if it's more complex, an hour and a half. And you then you move at the completion of surgery into what's called the recovery area, which is a sort of ward which is close to the operating theatre, to just check that you've recovered well from the operation and that you are good to go back to the ward.

And you'll typically then be given something to drink, maybe something small to eat. You return to the ward and we enter this phase of the operation where we begin your rehabilitation.

And I think patients are always surprised that the rehabilitate really starts the moment that you get back to the ward. So, in other words, you might find that if you've recovered really well from your anaesthetic, the physiotherapist will come and help you get up almost straight away and start walking. Clearly for some people who are a little older and frailer, who've got other conditions, that may be a challenge, but certainly for younger people - and I would say now it's the norm - we'll try and get you up and get you walking straight away. You can walk on a hip or knee replacement straight away and it's completely safe. And in fact getting going and walking early on is the safest way to manage patients because it improves your outcome, reduces your rate of blood clot and a number of other complications that can occur.

Now, in that first day, if you are having-, if you're really fit and well after the operation, even if you have other medical complications, if you recover in a way that's very, you know, there are no problems here and we've got you up and walking and it's all safe, then there's a certain group of people who will be able to go home, who can have day case surgery. And day case surgery and joint replacement, say, if I talk specifically around knee replacement, has really increased over the last 10 years, it's much safer and we're more experienced at doing it.

There are many, many patients say in the hospital I work at are suitable for day case surgery. You have your operation on the day, if all goes well, you've mobilised and you recover well in that first, say, six hours after the operation, it's entirely safe to go home. You need some support at home. So we couldn't send you home on your own. We give you tablets to manage your pain to help you avoid having a blood clot. All of the things we've thought about and helped you plan. And you can go home the same day. There are safety nets for if there are problems, there are people to contact. But it's safe to do that and many, many, many hospitals now around the country, in fact, I would say almost all will offer day case surgery for a percentage of patients who are able to do that.

Two things I think that patients would find reassuring here is that no one's trying to force people out of hospital if they're not ready to be out of hospital, so it's safe. The second thing is something that was surprising, I think, to even us, where we were trying to drive this day case pathway, is that - it's interesting - if you, it's entirely safe to do it and we've studied it and the complication rate-, and the satisfaction rates were very high, complication rate low, readmission rate low and satisfaction rate very high. And our observation, and I think this is a critical thing to take on board, is if you do a knee replacement on a patient and it goes well, when they come back, or if they come back to have the other side done, most of those patients request to have this done as a day case because of the advantages of getting back to the home environment, feeling that they're managing this partly themselves and actually this realisation that I think it's important for patients to understand that many, many patients don't want to be in hospital. It's an unusual and sometimes a bit scary environment. So getting you home is a good thing, if we can do that safely. So day case joint replacement surgery has really come of age and it's quite common. You might see this in 20 to 30% of patients who will be eligible for it. So don't be surprised to hear of that happening. But also if you're going to have a knee replacement, it might be something that's suitable for you as an individual.

Professor Andrew Price outlines what patients can expect in the early days and weeks of their recovery from knee replacement.

So once you've had your knee surgery and you've been through that process in hospital of getting to the point where you can go home, be it on the same day - day case surgery - or after 1 or 2 days, you'll go home and your rehabilitation starts. And I think it's important to focus down on this first six weeks after the operation.

So there's no doubt after total knee replacement that this is a difficult period because you've got to balance getting going, walking and getting the best out of the function of your knee, but also that the operation itself will produce swelling and a painful joint and if you push too hard to go too quickly with your rehabilitation, it's a really painful experience.

So the first six weeks, with help from the physiotherapy team who provide a plan for your rehabilitation, will be building up the amount of walking that you can do. You will use crutches to help your balance, but you'll be well to walk and fully weight bearing your knee. But you're balancing doing too much so that it's a bit too painful versus trying to do as much as you can to get the knee moving and to get the knee bending.

And I think we used to be-, we used to go too hard early on for patients to get the knee bending. And what we've realised is you can be a little bit more relaxed in that and it's what happens at the end of the six-week period; as long as the knee is starting to move, you're starting to get a range of movement which is now up to 90 degrees, so you can sit comfortably in a chair - that is the aim at the end of that six-week period.

But be aware that if you talk to patients who've had a knee replacement, everyone will say the same thing. It's a period which does have some pain associated with it. And we need to manage that with medications. We're much better at doing it. But that characterises that first six weeks.

A couple of things happen in the first six weeks. Typically at two weeks, you'll either come back to the hospital or visit your GP to have your clips removed or the stitches removed. So the wound checked and the sutures removed. Then at six weeks in many, I would say most, places where this type of work is done at the hospital, you'll come back for a check to make sure that all is well, that there are no local complications. Infections are not a problem. There's no blood clot, and everything's moving in the right direction. And at that point, you continue with your rehabilitation.

And at the six-week point, from that point forward, over the next 3 to 6 months, you make much more progress in terms of your mobility. By the six-week period, although your knee is still a little warm, swollen and tight, may feel a bit sore, your osteoarthritic pain in the vast majority of people has gone, and that that's such a relief to patients that they really see that and they feel the benefit.

Then getting over the operation and the swelling and tension and tightness in the knee takes another 3 to 6 months. When you see most people at six months, they are really very comfortable, moving well, and they've got a lot of benefit from it.

At the six-week period, you almost certainly don't have to use crutches or walking aid. You're able to drive and you can fly and move around and travel if that's what you'd like to do. So you're out of the early phase but you're now in this period of developing your ability to get back and do all the functional recovery that you would like. You know, where you're aiming for.

I think it's fair to say that if you are a frailer, more elderly patient, that another factor is that you are knocked back quite hard by the operation. You'll feel tired and washed out maybe for 3 to 6 months. If you're slightly younger, then you'll get over that bit a little bit quicker.

But when you see everybody say nine months to a year, that's when you see the real benefit in joint replacement. Their osteoarthritic pain is gone. They've returned to the level of function that they've achieved and in most cases it's higher than when they started out. And they feel very happy with the improvement in their quality of life. So I hope that gives you a kind of little summary of what to expect over these periods: in hospital having the operation, immediate recovery once you get home, that first six weeks which are tough, the next three months, which are gaining more and more confidence, and then by six months to 12 months where you just get on with your life and you've recovered essentially from your knee replacement.

Professor Andrew Price talks about how recovery from knee replacement surgery can be different for those with multiple health conditions.

So I think it's important, you know, just if we just focus a moment on that group of people who earlier I said perhaps who are slightly frailer, say, the more elderly population, or patients who have multiple other medical conditions. That the recovery dependent on those medical conditions and what happens in relation to them during that initial period of having the operation, your recovery can be slower.

So for a patient who has, say, a very strong cardiac history, has had a heart attack before or has a problem- a long-term problem with their heart. If you add to that, say, you have diabetes and you have a problem with your breathing, that patient doesn't recover at the same rate as a patient who doesn't have those other issues.

Of course in the shared decision making around deciding whether to have the knee replacement or not, these are all factored in. So these are not surprises to the patient; when you come forward to have it, these will have all been discussed with you. But that patient who does have other conditions going on, the recovery is a slower process. And of course we need to make sure that there's not an exacerbation of one of those conditions. For the patient who has Parkinson's disease, for instance, that may be more challenging in terms of your mobility. You may go backwards before you go forwards in terms of your ability to move.

The patient who has a problem with their breathing may find that it was very tough to get going early on because they're short of breath, but they slowly catch up.

So I think the speed of recovery in that first year is partly determined by some of these pre-existing conditions that you need to consider and need to be discussed at the point at which you're deciding to have the knee replacement. They need to be brought out and emphasised at the pre-assessment process before you have the operation, and then they need to be considered in your recovery.

Working hand in hand with the GP, the hospital and the GP working out to understand that that those patients may go a little slower. And as long as everybody's aware of that, the correct supports put in place to get them a good outcome. But I think it's also fair to say that as long as these things are managed well, that some of these, you know, multiple other diseases and the person who has a lot of health care burden is still eligible to have a knee replacement as long as they understand the risks and what it means for them.

And, you know, we are probably much better at managing this than, say, if you go back certainly 20 years ago. The key important thing is to understand that it's about the individual patient. And their issues around other healthcare conditions in the decision making and then in the recovery.

Thank you.