Phil Orrell

So good evening, everyone and welcome to our webinar from Benenden Hospital this evening on hip and knee replacement surgery. My name's Phil, I'm your host for this evening and I'm joined by our Consultant Orthopaedic Surgeons Mr Raman Thakur and Mr William Dunnet.

And just to give you an outline of the format of the session, our Consultants will talk for 20 minutes - a 20-minute presentation each - and this will be followed by a Q&A session. If you'd like to ask a question during or after the presentation, you can do so by using the Q&A icon at the bottom of your screen. You can do this anonymously, or you can give your name, but we should remind you that if you are giving your name that the session has been recorded.

If you'd like to book your consultation following the presentations, we will be providing you contact details at the end of the session.

Now that's quite enough from me for the time being, I will hand over to Mr William Dunnet.

Mr William Dunnet

Well good evening, everyone. It's great to have you all here with us this evening at Benenden Hospital. As you know, we're going to be with you for about an hour and probably the most important aspect is the Q&A at the end, but we'll try to be as informative as possible over the next 20 minutes.

So, the first thing I would say is that there's a lot of information out there on the net about hip and knee replacements. A lot of it is confusing, a lot of it is quite complex and - in fact - some of it can be downright gory if you pick the wrong YouTube video. So, I think it's much better for us to be able to give you a little guided tour and perhaps give you some constructive education as to what to expect. So, included in this session I'm going to be discussing a little bit about the Consultants that work here, the kind of volumes we get through in surgery and I’m going to cover hip replacement, some of the causes - it's usually arthritis, sometimes it's idiopathic sometimes it occurs as a result of trauma or infections. I'm going to discuss with you the consultation process, which is how we manage to get to know you in 20 minutes and run through the pros and cons of undergoing surgery and go through some of the conservative options that are possible.

And of course, we'll have to discuss the risks and complications, because surgery is a major undertaking and – unfortunately - things can occasionally (thank goodness very rarely) go wrong and I'll cover a little bit of something about the post-operative recovery and Mr Thakur will be doing some of the similar things to me. But also, he's going to be mentioning something about the technology and something we're hoping to adopt here in Benenden in a few months’ time which is using robotics.

But that's all in the future and it's something we're all getting rather excited about. Now I want the next slide, so Oli, can we have the next slide please? If not, I can -  oh here we go.

So, this is a little bit of something about me. I trained at Cambridge and then I moved down to Guy’s Hospital where I developed my interest in knee surgery and lower limb surgery in general. I've also trained at the Royal National Orthopaedics, and I spent a year out in Australia with my family, both in Melbourne and Sydney, and that gave me a great insight into what healthcare is like in other countries. It made me realise some of the great things we have in the NHS (and some of the not-so-great things we have!) and so it's given me a great perspective on how we can really relish and enjoy our service that we have here in medicine in this country - and how we can also improve on it. Next slide please.

So, at Benenden Hospital we are a leading provider of private hip and knee treatment, as described by the Private Healthcare Independent Network. They use several metrics; one of them is the quantity of operations we do - which is extremely high - but it's not just that. They look at the outcome measures of the surgeons that work there and they make sure that we're comfortably in the best quartile or second quartile in the country of our performance - and we're an experienced team of Orthopaedic Consultants and physiotherapists.

I would say the keyword here is team. We work together, we are professional colleagues that rely on each other's support and - for instance - as a team, we tend to get together every six months or so. We discuss things that go well, things that don't go so well in our form of professional meetings - and then we tend to go out for an Indian meal afterwards, in which case we just relax a little bit more.

But unlike most other people if they go out to Indian restaurants, who might discuss football matches, rugby or what we're going to spend our money on car-wise, I'm afraid to say we still discuss orthopaedics, because what we do is what I regard as being probably one of the best specialisms you can do in medicine, and most of us are like-minded. We get high patient satisfaction rates here at Benenden. I think that happens because we have a great atmosphere in the hospital. There's very little churn rate of the staff; the nurses, the physiotherapists, the ward staff they tend to stay here a long time because it is a happy place to work in and their managers look after us all very well. And we pride ourselves particularly on our rapid recovery program, which gets patients out of hospital within a day or two and back to their home environment, which is where they know they tend to recover best and really get the nicest possible recovery. Next slide please.

Here's the group of Consultants. As I say, we are a team. We are here to support each other. In certain other hospitals, particularly in London, I fear Consultants are very much competitors with each other. Here in East Kent, this area, we're not like that. We're here to support and offer each other our expertise and our experience and discuss difficult cases and we come together with good solutions. And I know if I ever have problems with my operations, if I'm not quite sure what's the best operation to offer for my patient, I can discuss with my colleagues, and they will always help me out. Next slide please.

So here we are. Here's the volumes we do. They're very high indeed, as you can see, compared to hospitals in the region. This is a sign that people want to come to see us for their hip and knee replacements; and we do a lot of them but in itself it's not a sign that you have any expertise in it - it just shows you do high numbers. I can promise you we have the expertise as well and it will become apparent from this presentation the kind of things we can offer you that perhaps other hospitals can't do quite so well. Next slide please.

So total hip replacement. We tend to offer it for arthritis of the hip and your journey towards hip replacement starts with the consultation; and we get to know each other then and we give you all the basic bits of knowledge you need to know to help you make a decision as to whether a hip replacement is the right thing for you at the time. And we give you other options that may or may not be available or suitable for you, such as physiotherapy, injections, manipulations and - even we don't do it in this hospital - you will hear about something called hip arthroscopy which is where you can do keyhole operations on the hip and you take away little bits of additional bone or soft tissue that might irritate in the joint and that can perhaps delay the necessity for hip replacement.

So, we'd then take you on the surgical journey that starts from informing you how to actually treat an arthritic hip conservatively, through to how to approach hip replacement. And we optimise outcomes by giving you all the information that's required to get a great recovery.

And of course, problems - we're good at problem solving - and that's what really highlights whether a hospital is good or great. You're a great hospital if you look at the problems face on and you come up with honest solutions with your patient. Next slide please.

Okay arthritis of the hip. It occurs because of wear and tear in the joint. If you look at these two slides here, the one on the left shows a pristine, lovely joint with a nice bearing surface. On the right you can see everything is looking worn out. You can see all these cysts in the bone around the hip, which happens when it begins to crumble, and these rough, bony spurs catch on the sockets of the joint and causes restricted motion and pain.

It tends to be a gradual onset, radiographically, but the extraordinary thing is you'll find patients say “That's absolutely fine. I was playing squash and going walking four or five miles a day” and then suddenly overnight they developed what they thought was a tenderness strain, a muscular strain in their groin and they say “Oh, it's a sharp pain but I just ignored it and then after six weeks it just hasn't gone away”. They then go and see the GP; they get an x-ray and blow me they've often got quite advanced arthritis. That's because, even though the radiographic process is gradual, it's almost like a light switch that can switch on and it will not switch off again when the brain becomes aware of arthritic symptoms. So that's one thing that does surprise patients about arthritis: the speed with which it can apparently come on.

There's no specific, single cause. Risk factors, sure, if you tend to be someone that has a strong family history of rheumatoid, for instance, you're more likely to get arthritis. If you've had trauma as a child or in your youth and you've fractured the bone around your hip, that's more likely to lead to arthritis because you have an uneven bearing surface, I'm afraid, and if you ever get infection in the joint - particularly what worries us is if you have an infant or a child that gets infection in the joint, it can rapidly destroy the articular cartilage and this can be responsible for arthritis in later years.

So, arthritis is not curable, unfortunately, not at the moment. But it is eminently treatable with one of the best operations available for improving quality of life and that's total hip replacement.

The joint preservation is something I alluded to earlier. It's when we do essentially keyhole surgery to smooth and trim and improve the joint surface for a little while. The average age of people developing symptomatic arthritis at the hip requiring hip replacement is 69, so you know there's still lots of good life ahead of you if you get your arthritis sorted out when you're 69. Next slide please.

So, the consultation. We find 20 minutes is long enough. Any longer than that you'll get bored of us, and you'll say “For heaven's sakes, this man is rattling on about nonsense. I've had enough of him!” But 20 minutes is good enough.

During that time, we'd like to take a detailed history to make sure your symptoms are consistent with arthritis of the hip, because sometimes it actually isn't the hip that's causing the trouble - it can be your back, it can be your knee, or it can be a more disseminated arthropathy such as rheumatoid that's actually giving you symptoms elsewhere. So, we have to really nail down the diagnosis. We like to do something called the Oxford hip score, particularly the physiotherapists, they’re great scientists and they love to assess the quality of their treatment and they will do the hip score for us. And then they will do a further hip score after the surgery when you've recovered to see how much you've improved. And part of our clinical assessment involves a physical examination to be sure that it's your hip that's causing the trouble rather than anything else.

We like a simple, plain x-ray which will show the arthritic hip quite clearly and then we can tailor an individual management plan - which doesn't always involve going straight to hip replacement. We often will recommend weight reduction, perhaps dietary supplements and maybe even physiotherapy, rather than considering surgery. Next slide please.

So, treatment options. If your BMI is over 40, we know that that can be associated with increased risk, such as infection or thrombosis when you have the surgery. And also, if you have a high BMI, it can actually contribute to symptoms being worse than they need be otherwise. So, weight loss can be a benefit for a lot of patients there. And so non-operative management is often something we try first.

Intra-articular steroid injections. Yes, we all consider them at times, but they don't cure the disease, they just delay the inevitable. So, we use them with - how can I put it - we are cautious, and we tend to use them in patients we want to do a manipulation on, where we know we'll improve the suppleness and the range of motion of the joint. And to help them along the way, we often give them a local anaesthetic with steroid to make it more comfortable, but that's one of the options that can delay hip replacement.

Physiotherapy, there's always a role to build up the muscles and build up the suppleness around the joint which can again delay the need for any more invasive surgery. But, at the end of the day, total hip replacement is what most patients end up coming to at the right time. Next slide please.

So, the surgical journey. We talk about this thing called pre-habilitation, prehab. That's about getting yourself strong and fit and ready for the surgery because, if your muscles are strong and you're nice and supple, it's easier to recover from the hip replacement. And also, it might delay the need for hip replacement because, if you do a lot of exercise beforehand, you might think that – well, actually I can survive like this for a few more years before I have the surgery. But once we've decided you're going to go down the pathway of surgery, you then need a pre-assessment clinic with the nurse and sometimes the Consultant Anaesthetist will have a chat with you as well if there's, say, a cardiac history or a history of blood pressure that isn't well controlled. We like to optimise all of that and input from an anaesthetist will help you as well.

So, we pre-optimise you, we've tried to make sure your blood pressure is under good control, your diabetes is under control, we get up-to-date ECGs - say you've had a pacemaker in and just to make sure that your heart rhythm is good - and then your rapid recovery protocol. What's that about? Essentially what it’s about, is giving patients information about the operation, information about the recovery process, information about what physiotherapists are going to do for them. And we give it to them before the operation, so you no longer have fear of the unknown. And then you find everything much easier. Next slide please.

So, the days of admitting people a day before surgery have long since gone. We're finding if people are in the hospital just for a short length of stay, they do much better, whereas if people stay in hospital for a week or so in a sense you become institutionalised and you lose your confidence - and then you find that you're perhaps reluctant to want to go home because you think ‘Oh can I cope?’, you know ‘I won't have the nurses to help me dress in the morning, I won't help have them to help me get to the loo and back’. Whereas if you're only in hospital for a day or two you'll actually get on much quicker and much better and we all know the best place to be to recover from surgery is in your home environment, where you have your own bathroom, your own clothes and it's just so much more comfortable there.

Spinal anaesthesia and sedation is what we prefer. A lot of my patients will say ‘Oh I don't fancy the thought of hearing all the hammers and knocks and effing and blinding from the surgeon during the surgery. I'd rather be asleep!’. Well actually you'll recover much quicker and better with less nausea, less side effects if you have a spinal anaesthetic. And if most anaesthetists were asked the question ‘What would they have for hip replacement?’ they would almost universally opt for spinal with sedation. So, I think that should tell you something about that.

We monitor you closely after the surgery, because sometimes your blood pressure can drop and sometimes your breathing can become a little bit erratic and so you might need a little bit of extra support and help during the first few hours after surgery. But, by and large, we get people back to their post-operative beds on the wards within an hour or two of the surgery, ready for their post-operative exercises in bed and getting yourself going.

It's a one- or two-night stay in hospital for weight bearing on the day of surgery. So, if we operate in the morning, we can get you up and about in the afternoon. If we operate on a late afternoon list, you might be allowed a rest in bed for the rest of the evening and get going the following morning. It depends how you're getting on actually.

Now we use this word ‘intensive’ physiotherapy. That sounds awfully intimidating. It isn’t intensive, it is more like it's supportive, cajouling Physiotherapy and we just try to tailor it according to how you're doing. You'll enjoy your sessions with a Physiotherapist, they will actually make you feel good. And you might be feeling a little nervous and distressed before you see them, but you will have a smile on your face once you've had your session of physio. And we do aim to do it twice a day to get you mobile nice and quickly. Next slide please.

So, day one post-op. The Resident Medical Officer will see you and usually the Consultant will see you on day one or day two. It does vary slightly. As I say, we work as a team here and we sometimes rely on our consultant colleagues to see you or sometimes it'll be the RMO that does the assessment, but there'll always be a medical assessment on the first day. And the physios will see you and the nurses will see you. So, there'll be lots of people pestering you and seeing how you're getting on. We like to get you on two crutches as soon as possible and even if you don't have stairs at home, it's a lovely exercise to do to ensure your control of your muscles is good. So, we prefer you do the stairs, even if you live in a bungalow. And we'd like to get you in your comfortable home clothes as soon as possible because, again, it makes you feel more relaxed, less stressful because you know you're preparing for your discharge home.

Post-op blood tests and x-rays are taken; blood tests because sometimes people can be a little anaemic, because they lose a moderate bit of blood during the surgery, and you might need some iron supplement to help you over the first three months after the surgery. The x-ray of the pelvis is always taken just to make sure all the components are in the right place, which they invariably are, but one thing we often do pick up on the pelvis x-ray is sometimes we inadvertently get some cracks in the bone when we put in a hip replacement. And this usually can be treated conservatively - but sometimes we do need to do further operations to stabilise the crack in the bone with screws and plates. So that's very important.

Okay we've gone on to day two. So, more physiotherapy as required, discharge home with telephone support. We don't generally give people routine physiotherapy but we're always available on the end of a telephone to orchestrate physiotherapy and give you advice about your post-operative recovery. And you go on anticoagulation for four weeks after the surgery and your follow-up is arranged with a surgeon for six weeks. Outpatient physiotherapy is tailor made for each patient; sometimes you have it locally, sometimes you don't have any at all until the six-week follow-up. It really does depend how you're going, and we chat with you over the phone to see how things are progressing.

And for the first six weeks you need precautions, because there is a risk of the head dislocating, so we like to make sure you're treating it gently and carefully during those first six weeks while you wait for the nice strong capsule to form around the hip that makes it good and solid for the rest of your life. Next slide please.

So, the six-week follow-up. You will then be having a physiotherapy assessment and you'll be seeing your Consultant. The wound is checked to make sure it's healed nicely and at that stage I'd expect you to be mobile with one crutch or a stick. Sometimes actually people are mobile without any stick at all at that stage. It really depends how you're progressing, and everyone is different, so try not to compare yourself too much with someone who's at your tennis club or whatever, saying ‘Oh well they got rid of the stick after two weeks!’ Everyone is different and it's no shame to still be using a stick or a crutch at that stage.

And also, we begin to relax the hip precautions because the capsule is forming; it's scarring up and it's getting nice and solid around your hip. And I think - is that me finished now? Oh no, we've got a few more!

So, complications. I am quite frank and open about the complications as we all should be and some patients tell me ‘Oh Mr Dunnet, you've terrified the life out of me!’ and all that sort of thing. I find if you know everything beforehand it does take away the fear of the unknown and people know that actually - the team are honest, we're straightforward we're upfront with you - so you are prepared for everything. And risks and complications, they happen, but they're all rare but I do cover them all nonetheless every time I see you in clinic.

The risk of infection is between 0.3 and 1.5 percent. It does depend on which studies you rely on, which country you're looking at, which kind of hospital you're looking at. But, in general, the ballpark figure is one percent as a risk of infection. And if you do get an infection after a hip replacement, it is undoubtedly a complete disaster. It will delay your recovery - often by many months. We often have to redo the whole operation and it's a real strain both for the patient, the family and certainly the surgeon. You know, we forget about all our successes, but when things do go wrong - which fortunately is very rare - you never forget about them. And you remember those patients for the rest of your career. So, it's a hard undertaking for all of us and it takes a good year to recover sometimes from an infection.

You can sometimes get blood clots and they're nasty because they can end up in the lungs, stops them working and that - I'm afraid - gives something called the pulmonary embolus which can kill you. But it is rare, thank goodness.

Nerve injuries. There are major nerves next to the hip and they can get stretched and bruised and probably in about one in 50 cases you will have some temporary numbness or weakness in the leg. But thank goodness, it usually settles. But probably in about one in 300 you will have some degree of permanent numbness and weakness in the leg.

Dislocation, yes that's more likely to happen within the first month or two after the surgery. It used to happen - I would say - probably one in 30, 1 in 40 cases. Now it has become very much rarer because we template the surgery beforehand to get precisely sized components fitting in there - and we've improved our surgical techniques. So, I would say dislocation, you're probably looking at about one to two percent of cases will get a dislocation but no more than that. And - if it does happen - we put it back in place, rest you for a day or two and then usually everything settles.

Leg length discrepancy is remarkably commonplace. You will often find people's leg lengths are four or five millimetres out of perfection. That's because we try to get a nice, stable hip at the time of the surgery and sometimes it's necessary to take out a bit of slack in the soft tissue and give you a slightly longer leg where we operate. It's usually not a problem whatsoever; the body adapts beautifully to that. Occasionally, though, we do need to give you some shoe raises.

And, inevitably, the implants will wear and loosen in time. But we expect a hip replacement nowadays to last for a good 20 years. Next slide please. Ah we have now finished. Over to my colleague, Raman.

Mr Raman Thakur

Hello everyone. I hope you can see me, and Bill thank you very much for an excellent talk on hip replacement.

I'm Raman Thakur. I completed my Orthopaedic training back in South India before coming to the UK and did a registrar rotation in the Southeast Thames region with the rotation between Kings and Guys Saint Thomas's Hospital. I spent a year in New York Lennox Hill Hospital in hospital special surgery doing a fellowship in hip and knee reconstruction. I work as a Consultant Surgeon in East Kent, specialising in hip and knee replacements, and I've worked at Benenden since 2012. Next slide please. Thank you.

So, knee replacements are fairly common operations. Over 100,000 of these are performed in the UK yearly, though the incidence was slightly lower following the pandemic years. But the numbers are coming back up again. The average age for patients undergoing this surgery - just like hip replacements - is around mid to late 60s and around 57 percent of these are in the female population.

Over 90 percent of people are pleased and happy with the outcome of surgery and report health improvement. And, just like hip replacements, knee replacements now last 80 percent over 20 to 25 years. Next slide please. Thank you.

Indications for knee replacement. Again, osteoarthritis is the most common reason why we operate and replace the knee. Rheumatoid arthritis has become a lot better managed with medical management and has become far less common a cause. I remember when we started training, we used to have about 30 to 40 percent of our patients with secondary to rheumatoid arthritis but that incidence is probably in single digits now.

Gout and degenerative conditions and inflammatory conditions due to chemical arthritis and if there is destruction of the joint then it may require a knee replacement surgery. Severe trauma involving fractures of the distal femur or proximal tibia can lead to subsequent post-traumatic arthritis and once conservative options fail then surgery in the form of knee replacement would be indicated. Sometimes in the frail and elderly, one may use a primary knee replacement as a way of getting them up and going fairly quickly after the injury.

Ligament injuries. Again, long term, if there is instability despite previous reconstructions and things and subsequent joint damage, they may need a replacement to stabilise and also relieve the pain in the joint.

A reason to do a knee replacement; in terms of aims, what we are trying to achieve is to relieve the pain and that would be the most important indication. Sometimes we might actually advise people not to go for a knee replacement if pain is not a major feature, because we can make the joint painful afterwards.

Secondary to relieving pain, improvement of mobility and function as well as trying to restore the alignment of the knees. Usually, with time, the knees can get deformed either into a bullet or knock-kneed and we might be able to address and realign that during the knee replacement surgery.

Younger patients (below the age of 55) their success rates and their satisfaction rates in looking at patient reported outcome measures seem to be much less compared to people who are around the 60 mark because they have got greater expectations, higher functional demands and sometimes the knee replacements are not always designed to achieve this sort of function, more often than not. So next slide please.

So, in the early phases of arthritis, patients present with stiffness and pain along with swelling. The pain is predominantly on exertional activity and sometimes they may notice clicking or grinding in the knee. With advanced arthritis, they also experience pain at rest. It may interfere with their sleep and gradually they'll notice that the leg or the knee is getting more deformed and, as a consequence, they're walking distances are reduced and they have a pain when they stand from a sitting position and a feeling of instability the first time they get going. Next slide please.

So, just like the hip replacement or hip arthritis, the treatment options are always non-surgical and surgical. We would like patients to optimise their weight if their BMI is high, modify their activity, use braces occasionally when things are bad, work with physiotherapists to strengthen their muscles and use simple analgesia on demand to help them mobilise and do the exercises. Injections may also help. More often than not you would have heard people having steroid injections, but we also – at Benenden - have hyaluronic acid, which can give relief of symptoms for several months. It is otherwise labelled as Durolane.

Surgical options in osteoarthritis include arthroscopies to help address any unstable meniscal tears, loose bodies, if there is catching. Small areas in focus of bone damage can be addressed with micro fracture techniques using an arthroscopy, but it is not something that - when there is a large area of destruction - is going to be effective. So, arthroscopy has got a specific and defined role in patients with arthritic knees.

In young patients, who have got heavy demand and would like to keep the movements of the knee fully -  and do quite heavy exertion activity going back - one may consider having a corrective osteotomy alignment to transfer the weight bearing into the much more preserved part of the knee. Suppose if the inside of the knee is more worn, the realignment would try and put pressure through the outer, good part of the knee so that then people can still carry on with their activity and perform. Eventually, with time, the arthritis will progress to the rest of the knee and will need knee replacements. But that can last a good 10-15 years. So, for young patients, certainly osteotomy would be something.

Joint replacements. Again, I will talk a bit more in detail with the next slide. Cartilage transplantation has been tried, again this would be something which would be fairly in the very early, early stage where there is a focal damage to the bone. It is not something that would be useful when there is more generalised arthritis, affecting a much bigger area in the knee. Next slide please.

So, knee replacements can be a partial or total replacement. With partial replacement, we address the most damaged part of the joint when it is focal arthritis involving either the medial or the lateral compartment or the patellofemoral joint. So, depending on which part of the knee is arthritic, and provided the rest of the knee is good - without any damage - then we would consider going ahead with replacing just part of the knee. So, we could have a medial unicompartmental knee replacement or a lateral unicompartmental knee replacement, replacing the outer side of the knee or the patellofemoral joint replacing the kneecap with the front of the femur.

If the arthritis is more advanced, and affecting more than one part of the knee, and patients have got symptoms related to more than one compartment, then certainly a total knee replacement would be the most suitable option. In a total knee replacement majority of the total knee replacements are done using the standard instrumentation. Over probably 80 to 90 percent of knee replacements in the country are done this way.

When there is a complex knee replacement i.e. previous fracture, which may have led to a deformity further up in the bone, or you have got metal work from a rod, or something from a previous fracture, or plate and screws further down then it may not be possible to do it using the conventional instruments. And in that case, the options are either to go and remove the hardware or to consider a slightly different way of doing it, using either computer navigation or a Signature knee.

Computer navigation uses a couple of pins and uses a computer to guide your placement of the prosthesis. Whereas, with the Signature, we do an MRI scan of the knee or a CT scan prior to the surgery and from that, the company will give us software through which we can work out the size of the implants as well as the correct placement of the implants, and they will provide us with moulded jigs which are specific to the individual. So, if you are having a Signature knee, those moulds will be specific for you. It can't be used for anybody else, and that will help us position your prosthesis in the right position and use the correct size prosthesis.

Constrained knees are much more complex, arthritic problems where you've either had a severe deformity or ligament damage with instability and subsequently - or indeed - bone loss from primary surgery and have to consider revision surgery then we are going for a more constraint knee replacement. Next.

Vanguard is the knee which is used at Benenden in over 99 percent of patients. It is manufactured by Zimmer Biomet and has a high ODEP rating. It is an orthopaedic device and equipment rating which is done by the Government as well as the industry and it has got either a ten - ten stands for the number of years - and A stands for the grading from A to C. Saying that an A star is the highest. So, the rating for Zimmer Biomet is 10A star for most of the prosthesis and 13A star for some of their prosthetic designs. 10-year survivorship in the National Joint Registry is 96.4 percent.

We implant this prosthesis using bone cement, which is used as grout, and as a spacer and not a glue. We will assess the kneecap at the time and probably in 50 to 60 percent of knees will have the patella resurfaced and the rest left alone, because trying to address the kneecap can bring on additional complications. So, if it is absolutely pristine, we would (most of us) would like to leave it well alone, rather than try and address or replace the patella. Next.

New technology on the horizon, which Mr Dunnet alluded to earlier. We are expecting robotics to be available in Benenden, possibly early next year, to give – again - further customisation and allow navigation and more precise positioning of the prosthesis in complex cases as well as routine surgery. Next slide please.

So, after the knee replacement, patients are transferred to the ward, and we manage the pain and sickness to ensure that patients are as comfortable as possible. The wounds are reviewed and occasionally the dressing may be soaked and may need to be replaced.

Early mobilisation is the theme, whether it's a hip or a knee. Get people out of bed and getting them moving the knee as soon as possible, preferably on the day if it is done in the morning - the next morning if the surgeries happen in the afternoon. The hip replacements usually tend to work by themselves. Knee replacement is a partnership. The surgeon puts in the knee, the patient has to work the knee, otherwise we will not have a happy outcome. It is important and imperative to take the pain medication and do the exercises to get a good outcome from it.

Subsequently, the next day, usually the x-rays are repeated. We check X-rays and blood tests and make sure these are all satisfactory, ensuring the progress with physiotherapy is appropriate and you're back on your feet, independent and safe using crutches and have done stairs. That is when patients leave hospital. And usually most of these most patients achieve this within two days. Next please.

Risks of knee replacement occur during surgery. The main concerns are blood loss (which may cause anaemia and may need a transfusion), damage to tissues, the nerves, the blood vessels, the bone, tendons is what we are operating very close to and they are at risk of damage. We take precautions to prevent collateral damage. During the recovery phase, we are concerned about ongoing bleeding and wound healing issues, infection - as already mentioned - is a big worry. If there is any concern and - as mentioned - can cause delayed recovery and multiple surgeries to get rid of infection if it has gone to the joint. Blood clots in the lung, blood clots in the leg and the clots embolising to lungs is a more common complication. However, we do give blood thinners and exercises and get people up and going and we also use pumps to help the blood flow during the surgery. All of these reduce the incidence of blood clots.

Stiffness and swelling. Stiffness, as I mentioned, working with the exercises is very important. Swelling in the leg can be there for several weeks or sometimes months post-surgery. Swelling of the knee may take anywhere between six months and for the knee to look completely normal may take up to a year post-surgery. So, yeah, it is not something to worry about; so long as the progress is happening, the knee will eventually come back and look normal.

Long-term failure may happen because of infection, wear of the joint material - the plastic - and aseptic loosening or a fracture which can involve the prosthetic area may cause loosening of the prosthesis and all these will require most likely revision surgery. Next.

There are some patient decision support tools available. You get information regarding the surgeon and the hospital on the National Joint Registry as well as the Private Health Network and you can also use the patient decision support tool on the NJR website at www.njrcentre.org.uk/patients/patient-decision-support-tool, which could help you in making that decision and understanding whether this is the right thing for you, and the right timing for having a knee replacement surgery. Thank you, next slide.

Phil Orrell

Thank you both for your respective insights into the treatment options and the surgical journey. We can now take some questions from attendees.

This person asks: when do you know you're ready for a consultation? Two years ago, an x-ray revealed I had the early stages of left hip arthritis, but I managed this through exercise. Some days are not so good, perhaps four out of ten, while other days are good.

Mr William Dunnet

Well, it's very simple really. If you're no longer enjoying a good quality of life (and I would say if you're getting four out of ten, that is not great) and hip arthritis is something that's eminently treatable, we have a wonderful solution for it. And I think time spent in having a chat with experts who see hip replacements every day of their working professional life is time well spent. So, my view is if you have any doubts and you're not enjoying a good quality of life, you need to see the surgeon or an Allied Healthcare professional who deals with hip replacements, sooner rather than later.

Phil Orrell

Okay, thank you. This person asks: can a partial knee replacement be revised in the future for a full knee replacement if needed?

Mr Raman Thakur

Absolutely, and that is the main reason why we consider partial knee replacements particularly in younger patients. We would see if the part of the joint is affected, we would rather do a partial because it is preserving the bone in the other parts and, more often than not, we are able to revise a partial knee replacement to a straightforward simple total knee replacement. So, it would be certainly worth a) trying to see if a partial knee replacement is appropriate - and two, certainly if arthritis progresses in the rest of the knee it can be converted to it.

Phil Orrell

Okay thank you.

Mr William Dunnet

May I just add something to what Raman has said? I mean both myself and Raman are very keen exponents of partial knee replacement and yet there is a misunderstanding that a lot of patients out there think it's just a temporary procedure, before you do a proper job - which is a full knee replacement. I promise you, if you select the patient correctly and the operation is done well (and technically it is a demanding operation to do) but if you select the patient well, and it's done properly it will last just as long as a full knee replacement. And yet the patient's satisfaction is a little bit higher. So do not be misled, it is a great operation.

Phil Orrell

Thank you. Our next attendee asks: are the hyaluronic acid injections performed under x-ray and is there a limit to the number of injections you can have?

Mr Raman Thakur

No, don't you don't need an x-ray to do the injection. The knee joint is fairly superficial, and we are able to get into the joint fairly easily. Most of the injections are done in the Outpatient Clinic and - sorry what was the other part of the question?

Phil Orrell

Bear with me. Is there a limit to the number of injections you can have?

Mr Raman Thakur

Yeah, so with hyaluronic acid usually company recommends that they are not repeated within six months. So usually, the wait is beyond six months. I have had patients who have had good relief of symptoms for seven, eight, ten months and they have come a year down the line to have them repeated. Certainly, hyaluronic acid injection repetition is not a problem, not as bad as constrained, repeated steroid injections.

Phil Orrell

Okay thank you. This is quite a long question; bear with me on this one! I have some severe superior arthritis with sclerosis cysts, osteophyte formation and obliteration of the superior joint space in a hip - but I'm not getting a lot of pain. Sometimes I have a bit of pain in my knee and lower leg. I can walk 10,000 steps a day so it's not impacting life yet. If I delay the operation, is this likely to make the hip a lot worse so an operation isn't going to be so successful - or will it lead to longer term knee or ankle issues?

Mr William Dunnet

Now, so that's a fascinating question. There are so many aspects of this, and I hopefully will cover all of them in the next minute or so.

The first thing is we don't understand where the real pain generators are in arthritis of the hip joint. You can often see hip joints that are completely destroyed, and the patient just describes a little bit of achiness from time to time. It may be related to what we call the intraosseous pressure; in other words, the kind of pressure in the bone, close to the hip joint that could cause you the kind of pain you have - for instance, if you have a - I don't know a pimple, a spot and it's about to burst - it hurts.

If you have bone under pressure, it hurts, but if you don't have high intraosseous bone pressure, then it doesn't hurt. If you don't have a density of nerve pain fibres in and around the hip, then it won't hurt. So, it is extraordinary you can have a destroyed joint that doesn't cause pain. However, if it is painful, then it needs to be sorted out with surgery. But if it isn't painful, then we would be reluctant to consider surgery.

So, we're now on to the next phase of your question. You described joint obliteration; you described sclerosis and cysts. So that is a joint that's very arthritic and most people that have a joint like that would have a hip replacement. But if it's not painful, you can delay it and the subsequent operation will not be (within reason) any more hazardous or any less efficacious. All that happens with arthritis in the hip is as it progresses, the bone begins to crumble, and the leg shortens and so the bone stock suffers and so you sometimes need to use augments or grafts to make the hip replacement strong again. But that is a very straightforward technique that we are all competent to do.

So, delaying the surgery within reason will not make the outcome any less effective or more difficult.

But, the other part of your question was, is it going to lead to damage to the joint above and below if you let the arthritic hip get worse? Well, this is a very interesting one. If the hip stiffens up, it inevitably puts increased load and strain on the back and the knee because they have to move more to compensate for the reduced range of motion in the hip. And one of our very good spinal surgeons, he is also a good hip surgeon, because he frequently has patients that come along with back pains and he's told by the spinal surgeon ‘I could operate on your back, it is a very technically demanding operation that has hazards, but if I replace your hip - which is also very stiff - it will probably improve your back pain as well’.

So, the answer is, you must be aware of the whole of the lower limb, including the back, and when we assess you in clinic, we will be cognizant of that and we will sometimes offer you a hip replacement, even if the hip isn't causing too much pain but because of the stiffness that's leading to overload points above and below.

Mr Raman Thakur

If I may just add, Bill, I think the important point also is that sometimes the arthritis does not always produce or present with pain in the hip. Knee pain can be the sole presentation of hip arthritis. So, there are people who have presented to us with just a painful knee and - when you examine them - you'd see that they have got an extremely stiff hip and any movements around the hip they are saying ‘It's the knee that hurts’. So sometimes that may be the only presentation.

So, people have come hoping for a knee replacement and ended up having a hip replacement from me. So that is also an important thing and if the knee pain is a significant feature, I think you should get it checked to see whether it is in fact your hip that is causing the knee pain.

Phil Orrell

Thank you. This perhaps segues perfectly into the next question. How long after a knee replacement can I have a hip replacement? I know that you can't give a precise answer because of many variables. I had a knee replacement on the 20th of February but I've considerable pain in my hip. I'm 77. Thank you.

Mr William Dunnet

There is no fixed answer to this, but I would normally tell patients that I like to leave at least three months in between for two reasons. One, I want to ensure there's no infection that has occurred in and around the knee that would predispose to a poor result from a hip replacement. I want to make sure the wound is healed nicely, and I want to make sure the risk of getting thrombosis is low. And sometimes you can get small blood clots that don't present clearly within the first six to eight weeks after the surgery, and it is best to wait for at least three months before considering going ahead with further major surgery. Raman, what do you think about that?

Mr Raman Thakur

I agree with you, Bill. I would also suggest that see how you're getting on at six weeks and, if you are, then you get on the list and by the time you come it will be about three months. And I agree that would be the rough time I would be happy to do as well.

Phil Orrell

Thank you, gentlemen. A two-part question here. I had a metal or metal hip resurfacing in 2008 and I think it needs replacing. How does the procedure differ, and does it make the procedure more difficult? And the second part of the question is: I also have osteoporosis; again, does this make procedure more difficult?

Mr William Dunnet

Now even though I'm presenting on hips, Raman has a bit more experience with the metal-on-metal revisions. So, Raman, may I field that question in your direction?

Mr Raman Thakur

Cool. So, I think the metal-on-metal hip replacements have been actually conservative on the femur side but sometimes they might take a bit of extra bone out on the socket side or automatically things will need to be reviewed and understand. The main reasons why metal on metal have failed is because of a) the metal ion debris that has been produced and secondly the body's reaction to that, which has produced a delayed type of hypersensitivity reaction causing - in medical terms - it's called an alval reaction, but basically it's a big sac-filled with fluid with lot of debris and reaction of the body producing big cysts around the hip and sometimes they can be associated with destruction of the bone.

So what would be important is - I don't know whether or not you have had yearly monitoring, so anybody who has had a metal on metal hip should have a regular monitoring of their metal ion levels and if they are raised then they need an ultrasound scan or a MRI to look for these cysts developed around their hips - if there is evidence that the hip is failing and there are problems, then certainly revising the hip would be the answer.

On the femur side, usually it is not a problem. You can convert it to a straightforward standard prosthesis. On the established side, it really depends on the amount of bone damage. If there is still a good bone stock in most people, it is then one can hopefully address it with a slightly larger socket and hopefully a straightforward hip replacement. But there may be more complex reconstruction on the socket side.

Phil Orrell

Okay, thank you. A friend has suggested MBST is a possible treatment for my knee arthritis. What do you know about it and is it effective?

Mr Raman Thakur

MBST. I haven't come across that acronym. Bill?

Mr William Dunnet

Nor have I, I'm afraid. I don't know what it is.

Phil Orrell

Okay we shall move on. Can severe hip arthritis cause sciatic nerve-like symptoms?

Mr William Dunnet

Ah well we're now back to very interesting concepts of referred pain. As Raman was saying earlier, quite often a patient will come to you presenting with knee pain and in fact it is referred from an arthritic stiff hip. Now, to help you understand the principle of nerve referred pain, I take you to, for instance - a heart attack.

If you're having a heart attack, the patient will often complain of pain within the arm. This is, again, the principle of referred pain. And why does that happen? It's very complex. The way an infant develops mapping of sensation and pain in their early years. They have their eyes so they can see where a stimulus seems to come from and, if they get pain in the finger and they can see something's pinching the finger, they then know it comes from the finger.

However, as a child, you will never have cardiac pain, so you never develop the mapping of understanding where that pain is coming from. So, when in the first time in your life you, say, have a heart attack the brain assumes that the nerve fibres that go to the arm (which are pretty much the same nerve fibres that go to the pericardium) are one and the same. And it thinks you're getting pain in the arm. The same thing as a hip. If you get pain in a hip, which you have never experienced before as a child when you are mapping out your pain pathways, but that same nerve fibre goes to the skin around your knee, you will think it's coming from the knee.

So now we understand referred pain we can now understand why back pain (which gives you irritation of nerve roots) can seem to give you pain that's coming from the hip or the knee. It is a very, very confusing picture and it requires a clinician to examine you carefully and then see where we think the potential pain generator is. And it does require a doctor to examine you, listen to the history to pick up the special clues to try to find out the real culprit.

Phil Orrell

Thank you. I think we're obviously quite pushed for time now; I think we've run over slightly so we'll have to wrap up the Q&A section I'm afraid. Apologies to all of those whose questions we didn't answer but if you've provided your name, we can get in touch after the event and answer your questions.

If you'd like to book a consultation, our Private Patients team will be here this evening until 8:30pm or 8am to 6pm, Monday to Friday. We are offering a discount to all attendees of this session with the terms listed on the screen.

Following the session, we will be providing a short survey, so we'd appreciate your feedback from that. Our next webinars will include cataracts treatment and shoulder surgery, so you can visit our website and find the details of those and sign up.

All that remains for me to say is thank you for attending this evening and on behalf of our presenters and our team here at Benenden, I wish you all the best and we hope to hear from you soon. Thank you and goodbye.