Louise King

Good evening everyone. I hope you're well and welcome to this webinar on hip and knee replacement. My name is Louise and I’m your host. Our expert presenters this evening are Mr Goddard and Mr Shrivastava, Consultant Orthopaedic Surgeons at Benenden Hospital. Their presentation will be followed by a Q&A session. If you'd like to ask a question, please do so by choosing the button at the bottom of your screen. You can do this without giving your name and it will be anonymous. And just to remind you that the webinar is being recorded. So, I’ll hand over now to Mr Shrivastava and you'll hear from me again shortly. Thank you very much.

Mr Raj Shrivastava

Good evening everybody, my name is Raj Shrivastava. I’m a Consultant Orthopaedic Surgeon and I’ve been practicing in east Kent for more than 20 years. My area of interest is hip and knee replacement surgery and one of the hospitals where I work is Benenden Hospital. In the next 20 minutes, I’m going to give you some relevant information about hip replacement so that if either yourself or somebody in your family is having hip problems, when you are considering hip replacement surgery, hopefully this will be of use to you.

Now just to introduce hip replacement to you. It is a very common orthopaedic intervention. In the UK alone we perform more than 75,000 hip replacements every year and the number is creeping year by year. It is a most successful intervention in orthopaedics. If you think about the concept of quality adjusted life years, it means that if you are doing any medical interventions then how much improvement is that intervention going to create - and how long is it going to last. And if that is the idea, then hip replacement is one of the best and the results are better than even coronary artery bypass grafting. The survival of the hip prosthesis has improved progressively, and it is approaching 20 years now and the patient satisfaction remains very high - more than 95 percent of patients are very happy after a hip replacement.

Just give you a brief history of total hip replacement. The turning point for hip replacement was in the 1960s and credit goes to this person, Sir John Charnley. He was an Orthopaedic Surgeon in the Wrightington Hospital, and he established the total hip replacement that we see nowadays. Before his time it was more or less an experimental surgery and people have tried for decades and decades to perform hip replacement but the surgical techniques were very primitive, the material used was not very good and most of the patients used to get an infection and used to get mechanical failure of the implants. So, infection and failure were more or less universal before John Charnley’s time.

John Charnley established the hip replacement as it is today, but since then we have moved on further. But it has been a further slow evolution of the technique. So now we have got much better surgical techniques. We know more about hip replacement materials and the survival of the hip replacement has significantly improved because of better biomaterials. Rehabilitation after hip replacement has been standardised and most hospitals follow some sort of enhanced recovery program. It means that the patient has been looked after in such a way that recovery is quick, and the patient gets back to normal physiological status as quickly as possible. Now I’ll come back to this monitoring aspect, so I’ll leave it like this for the time being, but I’ll talk about the National Joint Registry towards the end of my talk.

Now, the indication for total hip replacement. There is only one, simple indication and that is to control the pain and to restore the function from a damaged hip. Now if you think about this sentence, which I’ve just said, there are two components to it. The hip should be damaged, and it should be painful. It means if your hip is damaged on x-rays or scans, but you don’t have pain, do not bother having a hip replacement. On the contrary, if your hip is not damaged enough on x-rays and on an MRI scan and you still get pain in the hip, you still shouldn’t consider a hip replacement because your replaced hip is likely to be painful as well. So, both these components should be there: your hip should be painful, and, on investigation, your hip should be damaged.

The most important cause and most frequent cause where you get a damaged hip and painful hip is osteoarthritis at the moment (and that applies to more than 90% of the patients we see in our practice). There are other types of arthritis as well like rheumatoid arthritis, seronegative arthritis, psoriasis etc etc. There are a couple of other things; one of them is avascular necrosis and I’m mentioning this because it affects a relatively younger group of patients in their 40s to 60s. And what happens is that (there are so many reasons but, very often, we can't establish any reason) the blood supply to the ball of the hip gets cut off and hence it gets damaged and very painful and patients ultimately end up having a hip replacement. Nowadays more and more patients after a fracture neck of femur also have a total hip replacement to restore their function which can last for a long time - but it is an emergency procedure so, if you want to jump the queue, break your hip and you will have a hip replacement as an emergency.

This is just an example to show you an x-ray of the hip replacement. The hip on your left you can compare with the right and you can see that it is significantly damaged, there is no joint space left there. The ball and socket are coming into contact and there are multiple irregularities which are basically cysts in the bone. And this is what the arthritic hip looks like on an x-ray.

Now this is an x-ray and an MRI scan of the same patient who has got avascular necrosis. Concentrate on the hip on the right side and, if you look at the MRI scan, there is a triangular segment of bone where the blood supply has been compromised. And you can see the same appearance on the x-rays as well in this hip.

This is an x-ray of the fracture neck of femur on the left side. If you look at the right hip and compare with the left hip there is an obvious break there. So that's a fracture neck of femur. And this patient - provided he’s medically fit and there are no significant comorbidities - he will have a total hip replacement.

Now something about arthritis in the hip. There are two very common presentations of arthritis: one is pain and one is stiffness. The type of pain varies from patient to patient, but typical pain in a patient is in the groin. It radiates towards the front of the thigh and goes in the knee. There are exceptions here; some patients present entirely with knee pain and it is not very uncommon. And this is perhaps one of the easiest second opinions I give in my practice. Where there is a painful knee, you can't find anything wrong with the knee and - if you examine the knee or investigate it - there is significant arthritis in the hip - although the patient is getting pain in the knee.

Pain is usually related to activities like walking, running, doing exercises. There is sometimes pain in the night as well because the muscles are relaxed and as soon as the rough surfaces of the joint rub against each other, you start getting pain and it wakes you up. It is very common to see weather related symptoms and some patients are much more sensitive to wet and windy weather if they have arthritis and their symptoms are much worse. Now because of the stiffness, you get difficulty in climbing stairs, cutting your toenails (because you can't bend your knee) and getting in and out of the car - although once you are in the car you can drive alright, because your hip is not required for that type of function. But while you're getting in the car you have to learn this tricksy movement where you sit down on your seat first and then you swing your legs in the car.

So, suppose you have got hip symptoms and you want to see a specialist. Hopefully your diagnosis will have been established by your GP, by doing an x-ray on your hip, which would have shown damaged hip due to arthritis or whatever it is. Now when you see the specialist you might need more x-rays if you're significantly changed in your clinical situation and your pain is significantly worse; then almost certainly you will have another up-to-date x-ray. And the specialist will give you quite a lot of information; they will tell you what they think is necessary for you to know but, at the same time, you will have your opportunity to ask questions so you will know from your perspective about your damaged hip and what it should be.

Now the last thing I wanted to say is take somebody with you. I know at the moment we are still going through the pandemic and most of hospitals will not allow somebody with you, but let's hope the pandemic is over quickly and it is a very good idea to take somebody with you, so that if you forget something then he or she can ask on your behalf.

Now before you consider any surgical intervention (which is a major operation) you should try everything else, first of all to postpone the hip replacement if at all possible and make it as safe as possible. With that in mind, you need to try all the conservative means of treatment and the most important of them is to control your pain and that is by taking painkillers or anti-inflammatories. You can think about modifying your physical activities.

One thing is certain that the pain varies from day to day in arthritis so if you get more pain on a particular day, on that day you slow down, do less activity and take more painkillers. And if you are having a better day - not much pain - then you can be more active on that day. And you learn that you can do certain things better than others and you concentrate on those things. Now, I have mentioned here about walking sticks. Quite a lot of patients don't want to know about walking sticks, but it is a very scientific and very effective way to control the pain and improve your walking while you are waiting for your operation as a more permanent treatment. What it does is it shares your body weight - your body weight goes straight through the stick to the ground and your hip remains protected. Hence it is less painful.

Now suppose you have to have a hip replacement, then it is a good idea to optimise your health so that our intervention has got a better chance of success. And then we have to understand whether there are any comorbidities like blood pressure, is there heart failure? Then all these conditions need to be properly managed and optimised before your operation. Anaemia is a very common cause of postponement of surgery in our pre-assessment clinics, so we make sure that your blood level is optimised as well.

Weight management is again another thorny issue around management of arthritis in hips and knees. Most of us are quite happy to operate on patients up to BMI 40. If it is more then perhaps it makes sense to control the weight. There are two aspects of weight management. If weight is managed and controlled, then the pain is less and you might be able to avoid having a major operation for a while and - even if you have to consider pain management by taking painkillers - your pain management will be more effective if you can manage to lose some weight. And if you need a hip replacement, then it is a much safer intervention if your weight has been optimised pre-operatively.

[Sorry, there is a spelling mistake here it should be a pre-habilitation here on my slide. It means that anything which can make which we can do to make your operation safer.]

Now you will come for a pre-assessment and you will be seen by various health professionals during your visit. You will spend about two to three hours in hospital. This will usually take place between two and four weeks before your operation and you will be assessed by a nurse, a physiotherapist, if necessary by an occupational therapist and - depending on your co-morbidities - you might be seen by an anaesthetist as well. During this visit you will get quite a lot of information about your admission, about your surgical procedure, about your post-op rehabilitation and if there are any special requirements in your situation. And – the most important for a part of pre-assessment - is your discharge planning: what will happen when you go home, who is at home with you, how you are going to cope, who is going to take the stitches out? All these things will be the part of your pre-assessment and will be discussed with you.

Now coming to anaesthesia for hip replacement. Usually the type of anaesthesia which is preferred by everybody is a spinal or epidural anaesthesia. It means having an injection in the back. It is very safe, it gives much better pain relief post-operatively, blood loss is less and most of the patients are very happy with this technique. If you have got pre-existing spinal conditions like curvatures or painful spinal conditions with previous back surgery, then this technique might be difficult. And then there are alternatives. One of them is having a general anaesthesia which requires intubation to maintain your airway. And then obviously there are issues with post-operative pain management etc. But whatever happens, you always need a Plan A and a Plan B and all these plans will be discussed with you in advance. You can have a combination of both - you can have a general anaesthetic so that you don't feel the needle going in your back as well.

Now this is my favourite slide of this talk, but just to inform you that Ralph has never worked in Benenden Hospital! He has never been seen around Benenden Hospital.

Now there are so many surgical approaches to total hip replacement and surgeons are very innovative. They want to do things differently - we don't want to follow each other blindly - so we can approach the hip from different places. So, at the moment the most common approach is the posterior approach, which goes from your gluteal region. Second commonest approach is the lateral approach where we approach the hip joint from the side and the less common technique is going from the front and from the superior aspect, which is from the top of the hip basically. Whatever, there are pros and cons with every approach. We sort out something and we create another problem. So, the best thing is if you are not too fussy about how to have your hip done, leave it to your surgeon because your surgeon is better trained in certain aspect of these approaches etc.

Now, types of hip replacement. There are two types of surgical techniques we do, and these are around the fixation of the prosethesis. This one is cemented, which is the x-ray on your left where the prosthesis - after preparing the bone - has been fixed in the bone with a special bone cement and you can see bone cement. Another technique is the cementless technique where we don't use cement at all, and a prosthesis is used to fit directly in the bone.

The second type of consideration is the type of articulating surfaces in the hip which could be either metal on plastic (which is one of the commonest combinations) ceramic on plastic (that is the second commonest) ceramic on ceramic is the third common technique used and there are pros and cons with all these combinations. But first to metal on plastic and ceramic on plastic. These are the commonest and very well-tried combinations of materials used in hip replacement. I’m sure you might have heard about a scandal with metal on metal hips, and it is no longer used.

Now, after the hip replacement, you will spend the first hour or so in recovery and then you will be sent to a special orthopaedic ward and you will be closely monitored for your pain management, any other issues like sickness, wound care and you will start mobilising as soon as you are comfortable and you are recovered from your anaesthetic. You will be watched for urinary retention, especially if you had a spinal injection then obviously your bladder gets paralysed as well and there is a significant risk of having urinary retention as well (it is much more common in male patients) and you will have post-operative x-rays just to check the position of the implant.

Now this is all very rosy and very routine work, but any operation carries some risks. These are all potential risks. We’ve hardly ever come across any problems but, still, it is worth knowing all those potential risks.

So, first of all, during surgery, we can face excessive bleeding from somewhere and - if you lose quite a lot of blood - then you might require a blood transfusion. We did an audit in our department recently and our incidence of blood transfusion following hip replacement was about two percent, which is not bad at all considering the extent of surgery. We can damage the bone with our instruments or processes, which could be in the form of a perforation with one of the instruments or a crack in the bone and - if that happens - then obviously you have to change your technique and do something extra to overcome the damage done.

Leg length discrepancy is not common. I mean, we say that there’s about a 95 percent chance that the patient won't feel any leg length discrepancy. Up to one centimetre of leg length discrepancy is relatively common but it is not felt by the patient. You hardly ever have to do something about leg length discrepancy and it usually involves putting a shoe raise on the shorter side.

Sciatic nerve injury is more common with the posterior approach to the hip because it is so close to that approach. Sometimes it recovers and sometimes it could be permanent and, if that happens, you get a foot drop and some loss of sensation in your leg.

Now during immediate recovery (which is first two to three months) you can get wound problems which could be a leaky wound. Then, invariably, you worry about infection in the wound. You end up having more treatment either to prevent or treat the infection.

Risk of blood clots is real and if we don't do any preventative measures then risk could be up to 15 to 20 percent. But everything is managed in such a way that risk is very low indeed. So, what happens is that most patients receive some sort of anticoagulation. So sometimes some surgeons use injections; I personally use a tablet which is used for five weeks that thins the blood and reduces the risk of blood clots significantly. It is not just the blood clot in the leg; occasionally the blood clot can go into the lung and that is a pulmonary embolism and it is quite a serious risk. It happens very, very rarely and the risk of pulmonary embolism is less than 0.5 percent.

Dislocation of the artificial hip. Patients worry quite a lot. If you talk to patients during my pre-assessment or consenting them, if I ask the question “What is your most important concern?” most of the patients worry quite a lot about dislocation of the artificial hip. But, in reality, it is extremely rare. Prosthesis and the techniques are such that the rate of dislocation, the incidence of dislocation is extremely rare enough really, we can’t remember when we’ve seen a dislocated hip after a straightforward hip replacement. It is much more of a problem after revision surgery.

A limp in the immediate postoperative period is relatively common and most of patients recover in about three months’ time. A limp is more common in people who use the lateral approach to the hip because you are going through the important muscle we call the gluteus medius, which prevents the limp but - even in this approach - most of the patients recover from a limp in about two to three months’ time.

Now complications are in the form of infection. That can happen anytime. It is usually blood borne. So, say, for example, you get an infection somewhere else in the body, that infection can travel through the blood and settle down around your artificial hip and that risk remains throughout the rest of your life. Dislocation can happen late as well and most of the dislocations (although they happen in the first three months) there will be an occasional patient who will dislocate afterwards.

Implant failure can happen, usually in the form of wear or loosening of the prosthesis and if that happens you invariably end up having revision procedures.

Now finally I’m going to touch on the National Joint Registry as promised. This is one of the best things which has happened to orthopaedic surgery, joint replacement surgery which include hip and knee and shoulder and elbow and everything. Now I’ll give you some background here. As I mentioned, there are about 75,000 hips done every year there are more than thousand surgeons doing hips then 200 implants available in the market to do a hip replacement.

How things can go wrong in that combination? You can think about it and things have gone wrong in the past. Some of you might be able to remember the 3M Capital hip from about 15/20 years ago and most of them failed in about five years’ time - and the majority of patients required revision surgery. And hence to avoid this, the National Joint Registry was established in 2003. It monitors implants, it monitors hospitals and it monitors surgeons. So every year the hospital gets the report on their performance figures; how many procedures have been performed, what is the failure rate, what is the revision rate, mortality rate etc. And if somebody becomes an outlier then it is spotted straight away that this person (either the surgeon or the hospital) is an outlier. There are more problems here and that can be sorted out right at the beginning, rather than facing the problems later on.

And one more important concept has happened is PROMs and that is patient-reported outcome measures. So, what will happen is that once your data are in National Joint Registry, most patients will get an invite to give your feedback at a certain stage. How they felt, what are the changes that have taken place, whether the intervention worked for them or not and all this data will be fed back to the system to the hospital and surgeon.

So, anybody can log on to National Joint Registry and see specific information either about the hospital and the surgeon as well. You just need to put the name of the surgeon and you will get all the relevant information about that person: how many procedures have been done, what is the mortality and if there are any issues and how does that surgeon compare with other surgeons. So, say, for example, I have taken this snapshot about Benenden Hospital so you can see how many procedures are getting done and how it compares with the national average.

So, this brings me to the end of my talk and I’ll swiftly hand you over to Mr Richard Goddard. He's going to talk to you about total knee replacement.

Mr Richard Goddard

Thank you, Raj. I enjoyed your presentation very much, especially enjoyed the slide with the caveman anaesthetist but fortunately he doesn't work here!

So good evening everyone. My name is Richard Goddard and I’m a Consultant Orthopaedic Surgeon specialising in knee surgery. As Raj has already indicated, hip and knee replacements is a very common operation and - in fact - there's slightly more knee replacements every year performed than hips; approximately 94,000 in the UK every year and I’m responsible usually for over 300 of those, most years.

So the reasons people have a knee replacement? The most common is osteoarthritis but, similar to the hip, other types of arthritis can kind of affect the knee: inflammatory arthritis, rheumatoid arthritis and other problems - commonly sort of post-traumatic. If you've injured the knee in some way, then you can develop secondary arthritis.

What is osteoarthritis? Well the normal joint is lined with lovely cartilage and that cartilage is smooth and when I look inside the knee with keyhole surgery, in a perfect knee the cartilage would look smooth and shiny and have the appearances of a cue ball in billiards or snooker. With arthritis, that nice, shiny, smooth bearing surface becomes damaged and worn and you see little bits of cartilage peeling off and beginning to flake away. And eventually, over the passage of time, you get areas of exposed bare bone and - when you the subchondral bone on the thigh bone and the shin bone (the femur and the tibia) then touch together then that's when patients have severe arthritis and severe pain.

So here we can see an x-ray. The x-ray on your left is a normal knee and what we're looking at is the space, the black space between the femur and the tibia. And the x-ray on the right-hand side we can see on one side of it the bones are actually physically touching together, and this patient has severe arthritis of the knee. And I’d expect them to have stiffness, pain and difficulty walking and difficulty - you know - physically moving and bending the knee.

So what are the causes of osteoarthritis? Well, just the passage of time. The knee is a major weight-bearing joint and just as one gets older, the wear and tear takes place and the cartilage can wear away. Similar to the hip, being overweight and having a high BMI puts more load and more force through the knee joint and this is now a major contributing factor to wear and tear and arthritis of the of the knee. People who've had a physical job, physical labour and those who’ve enjoyed sports in their younger years can also put excessive force and wear and tear on the knee. And also, people who've had injuries such as ligament tears and tears of the meniscal cartilage and needed keyhole surgery in the past - this can then lead to secondary arthritis and all these are common causes that I would see.

So what are the symptoms? At first you might not notice a great deal. You may just have a bit of pain on excessive activity; perhaps you can walk five miles but when you walk a little bit further your knee gets a little bit stiff and sore. Some people have swelling of the knee, a sensation of clicking and crunching, a grinding sensation going up and down stairs and people may complain that their knee is a little stiff first thing in the morning. As the arthritis progresses, people can get pain at rest just sitting in a chair, reading the newspaper, your knees are aching and throbbing. And - similar to what we've heard about the hip - you can get pain at night when you're lying in bed. The muscles are relaxed and then you suddenly wake up with this unrelenting pain and - unlike the hip - you get more noticeable deformity. People notice their knee becomes bowed so much that they have bow legs or they develop sort of a knock kneed appearance and patients, relatives and friends may notice that the shape of their legs have changed and their walking distance - your ability to walk - gets less and less, such that people can then only walk a few yards and eventually then struggle to get around the house.

So, arthritis goes through a few stages. We grade arthritis from one to four and this is mainly the appearance of keyhole surgery but we consider a knee replacement in most people where they have severe arthritis of grade four, where all the cartilage is worn away on one side of the knee commonly and the bones are physically touching together. The other stages of arthritis we try where possible to use other non-operative methods to try and control the symptoms and pain.

So, the treatment for osteoarthritis. Before rushing into surgery, you have to try modification of activities: losing weight, trying to strengthen the muscles around the knee, people would try painkillers - simple analgesics you can buy from the chemist - and then more stronger painkillers that your GP can prescribe. You could come to the clinic at the hospital where we may try an injection, a steroid injection, knee strapping, walking sticks and - when all these simple measures have failed - then we may consider an operation.

The most common operation is a type of knee replacement but occasionally, if it's not bad enough for that, keyhole surgery could be considered. And sometimes in younger people, trying to realign the knee with an osteotomy could be considered to try and make the force move to a less damaged side of the knee.

With knee replacements, there are many, many different types but just to mention a few. You can have a part of the knee replaced - commonly the inside of the knee - and a very common procedure is what's called the Oxford knee replacement. You can replace the kneecap joint. The more common type of knee replacement is a total knee replacement of which there are many different methods of doing it and we'll touch on a couple of those later on. And then come very specialist operations for very severe deformity, ligament failure and people who've had a knee replacement many years ago which has subsequently worn out and failed.

So what is a knee replacement? In essence, it's very similar to a hip replacement. You're cutting away the arthritic surfaces and you fix to the bone either with bone cement or an uncemented technique. A metal resurfacing of the end of the femur, the thigh bone and there's a metal tray fixed to the top of the shin bone and in between the metal components is a plastic bearing. Unlike hip replacements, knee replacements are usually always metal on plastic design.

So here we see someone, a patient with very, very severe arthritis of the knee. We can see both of their knees are very bowed, especially the one on the right side. And then afterwards, this is an x-ray of a knee replacement where we see the arthritis is being cut away. And on the x-ray in the middle picture you can see the knee is now nice and straight and that's corrected the deformity.

Some patients leave an arthritic knee for whatever reason; they're scared of hospitals, try to ignore the pain and the arthritis can progress. And it can progress to such an extent that the deformity gets very, very severe and here we see this poor patient has ignored their knee and now they've got very severe bone loss. Surgery can still be done, but the operation is more complicated. There's more risks and the eventual outcome of leaving it too late is that the knee replacement probably doesn't function as well as if you've had a more simple type of knee replacement.

Some people with very severe problems (commonly revision surgery or those with significant bone loss or severe deformity) actually have a knee replacement that's physically linked together, and we call that a rotating hinge knee replacement. But the vast majority of people I see don't require this very complicated and invasive operation.

So here we see an x-ray of someone who sadly dislocated their knee replacement. Dislocation, similar to the hip, is very, very rare. With the knee replacement, I can't remember the last time I saw it, but this person had a successful knee replacement but, sadly, a number of years later I think (if I remember correctly) they fell off of a stepladder while doing some DIY and they dislocated their knee replacement, tearing all the soft tissues and ligaments and their knee was very unstable and they needed it to be revised to one of these hinge knee replacements. This is not to say ‘Don't do activities you enjoy’ but with any artificial joint you need to essentially look after it, keep the muscles strong and try to avoid doing anything that's very high risk.

So what are the requirements of a knee replacement? Well, we're trying to - for the patient - obviously get rid of symptoms - the main one being pain - restore the alignment and restore the patient's function, their ability to walk and bend and flex the knee. However it's been shown with knee replacements that if the knee replacement isn't put in as accurately as possible, if it's out of the weight bearing and mechanical axis, then the amount of time the new replacement lasts is very much reduced and the implant can fail quickly. So, it's very important to try and get a knee replacement that's done as accurately as possible. And there are a number of techniques that can be used during surgery to try and ensure this as much as possible.

Here we can see an example of what happens if a knee replacement is put in badly. This knee replacement was put in slightly at an obscure angle and, over a few years, with passage of time the bone eventually gave way and fractured and this patient has had catastrophic failure which then would need revision to probably one of those hinged knee replacements.

So, there are many, many techniques we can use to try and avoid implant malalignment. The most common technique is to use instruments in theatre where the surgeon who's specially trained would use your x-rays and MRI scans and use instruments to align the implant during the operation to the thigh bone, to the hip and the ankle by usually inserting guide rods down the middle of the bone during the operation. But times are changing. People have greater demands, people are doing more extreme sports, people have higher expectations and patients are generally getting younger and younger who require a knee replacement and we're wanting the knee replacement now to last longer than we wanted it to last, say, 20-30 years ago.

I’ll quickly go through a technique that is relatively new, but it's probably been around now for a good nine to ten years. But it's a good technique of obtaining a more accurate alignment in selected patients where it's appropriate. This type of what we call ‘Signature knee replacement’ is not suitable for everyone but, in certain circumstances, it can aid the surgeon to get a very accurately aligned knee replacement.

So, unlike a standard knee replacement, we tend to do a Signature replacement in patients who have had previous trauma. So we can see this person has got deformities of their thigh bone and shin bone and I’d find it very difficult to put a guide rod down the middle of these bones during the operation, due to the previous fractures and the bones have healed in a slightly deformed way. So, using another technique here would be very useful to those with severe abnormal anatomy, previous fracture and - in some instances - younger patients, then the Signature knee replacement can be considered.

So what is Signature? In essence, I’ll whizz through it, but you would come to clinic and have x-rays as normal, be diagnosed with arthritis and then - if you're suitable for a Signature knee replacement - we would get either MRI scans or CT scans of your knee, your hip joint and your ankle. And then a specialist computer program analyses the data and then sort of decides how much bone and cartilage to shave away from the relevant areas.

If the surgeon desires, with the computer program you can do sort of the knee replacement a trial run. You could say on the computer (and here we can see just some computer images) where you're deciding how much bone to take away to correct the deformity and then once you're happy with the surgical plan it's accepted. And specialist guides are created which are made for the individual patient. So, with this technique, we're trying to restore function, correctly align the mechanical axis of the leg which would then allow pain relief and hopefully increase mobility to these patients.

So the guides are specific to the patient and these white guides you can see are placed during the operation on the bone, and the little holes you can see in the guide are where drills are passed which then direct the saw cut. These are thrown away at the end of the operation - they're not implanted - and it's important to stress that the knee replacement you get is exactly the same as it would be if it wasn't Signature. It's just that these guides are helping decide how much bone to take. The knee replacement itself is not specially made for the patient, it's an off-the-shelf knee replacement like all the others.

And one hopes with any knee replacement that you get accurate sizing of the components, so the metal components don't overhang and irritate the ligaments and soft tissues. An accurately placed knee replacement, and usually a good correction of the deformity, a nice straight knee which then correlates to a good range of movement of the knee on the table. With any knee replacement it's really important to stress that having the operation is step one, but step two is doing all of the exercises - physiotherapy which is just as important as the operation. If I do a nice knee replacement on someone and they sit at home nursing a sore knee and don't move, it will get very stiff and a stiff knee usually becomes a stiff and achy knee. So, it's really important after a knee replacement to do all of the exercises as often as you're required.

So yes, theoretically, there's less trauma during the Signature knee replacement but this is probably small print, and the operation can be slightly quicker. But then again, you're only shaving 5-10 minutes off the operation, so again it's small print. The main benefits are in patients who've got a severe deformity where a standard knee replacement is going to be more tricky for the surgeon to do.

So, with all knee replacements, we do a rapid recovery here at Benenden -  which is essentially a multi-disciplinary approach with the surgeon, the anaesthetist doing the correct anaesthetic so that you can get up out of bed hopefully the same day, the nurses, the physios are specially trained to get you up and about the same day and try to get you standing; just doing a few steps, perhaps from your bed to your chair or your bed to the loo, just to give you confidence on day one that the knee replacement is functioning. And then most people would stay in hospital just two nights. Occasionally an extra night is required if you have a poor first day due to sickness or that type of thing, but it's then all down to the patient to get the knee moving and rehabilitate and exercise the knee.

So that's the end of my talk. I hope it's been rather informative and both myself and Mr Shrivastava are open to any of your questions. Thank you.

Louise King

Thank you, Mr Goddard, Mr Shrivastava. Okay let's see which questions we have. So, let's go with the shorter one first.

Anonymous person says they are worried about receiving a general anaesthetic or a spinal anaesthesia. What should they expect?

Mr Richard Goddard

Shall I answer this one, Raj? I mean to have a major operation, hip replacement, knee replacement is a major operation. You're surgically - you know - cutting the bone, which is like doing a controlled fracture, so afterwards it's quite painful. Hip replacements tend to be not as painful as knee replacements, but clearly you need a major anaesthetic. We try, for most people, to do a spinal anaesthetic, which probably sounds worse than it is. Usually the anaesthetist would numb the skin in your back with a little fine needle of local anaesthetic and then they pass a very fine needle in through the gap between the bones in your spine and, I mean, I’ve not had it done myself but I’ve seen it witnessed and it's not terribly painful.

You may feel a bit of pressure and then, once the anaesthetist is happy that the needle is in the right place, the anaesthetic drugs are injected which then - after five to ten minutes - the patient would feel their legs gradually becoming numb from the waist down. A lot of people don't like the idea of just having a spinal anaesthetic where you can hear the operation, you can hear the surgeon talking, you can hear the saws and the hammers. Orthopaedic surgery is about sort of impacting these implants into the bone, which tends to be noisy, so the anaesthetist may give you some light sedation or a light anaesthetic so you're sort of dozing off and not aware of the operation.

But the beauty of a spinal anaesthetic is - when you recover, when you've had the operation - you're usually not feeling sick, you're talking, you can sit out of bed and your pain is very much controlled. And the pain comes back very slowly, such that you feel sort of a bit of a warmth at first and then a dull ache. And when you feel that dull ache, you would ask the nurses to start giving you oral medication and pain relief before the severe pain kicks in. If you just have a general anaesthetic (which often we try to avoid) once the anaesthetic is switched off, then the pain is there and you need strong painkillers, you know, from the minute the anaesthetic stops. So spinal anaesthetic is the way forward and I think it often sounds worse (and the fear is worse) but it's not as bad as it sounds!

Louise King

Great thank you. Raj, we have a question. Someone says if you're in the early stage of hip pain with no confirmed x-ray showing osteoarthritis, is physiotherapy the first course of treatment? They have an appointment with specialists next week and believe this will be with the physio first, not the surgeon.

Mr Raj Shrivastava

Okay so this physiotherapy appointment which somebody is going to have is not for physiotherapy. Probably it will be for your assessment to see whether you need any specific diagnostics like x-rays, MRI scans etc and only after that, if the arthritis is mild and you are not taking enough painkillers in the first place, then perhaps you will be sent to a different physiotherapist to give you some treatment in the form of physiotherapy. And yes, that is very appropriate. Physiotherapy can help. It is a mixed bunch, actually. Obviously it does not work for every patient but anything which can postpone a major intervention is worth a try and it is a good technique and quite a lot of time it does work quite reasonably OK -  especially in combination with some painkillers.

Louise King

Great, thank you. OK, this lady's mum has arthritis in the knee. She had a stroke aged 55, is on lots of medication and has been told a knee replacement is out of the question. She is now 78. The OT tells her not to work through the pain but she's old school and keeps going, albeit slowly. Would anyone consider her these days for surgery?

Mr Richard Goddard

It's very difficult without seeing the individual patient. Some strokes are very severe and someone with a dense stroke who sadly has lost the use of one side of their body and is not able to walk great distances probably wouldn't do well with a major joint replacement. In some cases, it can be done purely for pain relief but - if the person is not able to do their exercises and not able to move the knee and mobilise - they're likely to suffer significant complications either immediately after the operation or complications of the knee replacement, such as stiffness. And if that happens, a number of patients can be no better or sometimes worse than when they started.

So, I would probably say the patient needs to be assessed by a specialist. I’d be more than happy to do that myself, but we try to avoid major surgical intervention in patients who we feel are not going to do terribly well following the operation.

There are other things available, types of injection can be considered, knee supports, knee braces and this type of thing in patients who've had strokes can be quite helpful. But it really depends on how severe the stroke is: can they walk, can they function and are their muscles strong enough to be able to walk and rehabilitate after a major operation.

Louise King

Thank you. OK, Christopher asks is it unusual to have a double hip replacement?

Mr Raj Shrivastava

It is unusual in the sense that technically it is possible to do both the hips. Perhaps Christopher is asking about having both the hips done in the same sitting? It is technically possible, but it is not necessary. The best thing will be to have one hip done, recover well, make sure you are happy with what has already been done, before you subject to your second hip replacement. But yes, technically surgically, it is possible to do both the hip replacements together. But my personal opinion is that it should be avoided.

Louise King

Thank you. And Carol says I’ve heard that you cannot kneel on a replaced knee. Is this the case still?

Mr Richard Goddard

I get that question asked a lot in clinic and I would say it's true and it's false. It's physically possible to kneel on a knee replacement, so I usually say let the wound heal. Certainly, you shouldn't be trying to kneel for a good six weeks. Let the stitches come out, let the scar fully heal, massage the scar with sort of creams and bio-oil to get it nice and supple and then start trying to kneel on something soft. Kneel on a cushion, kneel on the sofa and kneel on the bed. Get the knee used to the pressure of kneeling and also get the movement of the knee, the flexion of the knee, the bend of the knee such that you can physically kneel. Then, once you've got the knee accustomed to kneeling, the range of movement satisfactory, you can kneel down to plant some bulbs or you know change a plug for half an hour on something soft like those cushions you can buy from the garden centre. But you shouldn't be kneeling for hours on end, fitting a carpet that type of thing.

Louise King

OK, thank you. And Helen asks, is there any way of determining that all the pain is from the hip rather than from lower spinal discs?

Mr Raj Shrivastava

This is a very relevant question and we do come across this problem again and again and again in the clinic. And very often we end up sending the patient to a spine clinic to get their opinion and the usual reply is that if there is a problem in both the spine and hip, it is very difficult to be sure because - although the pain is in the hip joint - it is felt through the spine, through the nerves. So sometimes we can give blocks in the hip and see whether that helps. So, if you give a local anaesthetic injection in the hip and that gives very good pain relief, it means that there is a significant contribution from the hip itself.

But if you have got a problem in both your spine and hip, then the usual situation is that a spine team will advise us to sort out the hip first because it is easy to do and whatever is left then is fine, people can tackle that problem. But yes, it is a very relevant question and a very important situation - very common as well in the clinical situations.

Louise King

OK, thank you. Leslie asks does your body attack the implants as an invader?

Mr Richard Goddard

I would say that's very, very, very rare. The metals that are used in both hip and knee replacements are biologically inert; they're made of cobalt chrome. It's very, very, very unusual to reject a hip and knee replacement in the true sense, like you could reject say a liver or kidney transplant. People who've said they've rejected an implant it's commonly there may have been sort of a very, very subclinical low-grade infection causing the problem. There is a rare instance where people may be allergic to a type of metal and nickel and - if we're very worried about that - sometimes we send people for skin patch testing to see if they have a metal or nickel allergy. If that's the case, we can use implants that don't contain - or have a special coating to avoid - the nickel which is the most common metal to be allergic to. But if you're allergic to nickel and you had an implant with nickel in, it would usually cause ongoing discomfort and pain rather than someone rejecting the implant.

Louise King

OK, thank you. Our last question – because we’re just running out of time - in what situations might hip lining be preferred to hip replacement?

Mr Raj Shrivastava

Hip lining? Perhaps this question is regarding hip resurfacing and hip resurfacing used to be a very good technique. We used to do hundreds but because the articulating surfaces were metal on metal that's why this operation has gone into disrepute now. So, this particular procedure is only a special situation procedure, not available commonly in all the hospitals.

Perhaps the last famous person who had hip resurfacing is Andy Murray and - in general - it was a very good intervention. But, because of the metal on metal problem, I think it is better to avoid this particular intervention and go for some sort of special component hip replacement where the life of the component can be improved by either using a ceramic head or ceramic on ceramic (both surfaces ceramic) and that serves the purpose.

Louise King

Great. Well thank you both very much for your presentations this evening. It's really interesting. And to everyone watching, you'll receive a short survey after this presentation so I’d be really appreciative if you could spare a few minutes to fill in the survey as your feedback helps to shape future presentations. Our next webinar is on the 28th of September at 6 00 pm it's with General and Colorectal Surgeons, Mr Marzouk and Mr Adamek. So, if you join that you'll hear about the private treatments we offer for treating haemorrhoids which includes the Rafaelo treatment. So, on behalf of Mr Shrivastava and Mr Goddard, myself and the Benenden Hospital team I’d like to thank you so much for joining us this evening and I hope we see you again soon. And please, if we haven't answered your questions, please don't worry we will answer them afterwards. We’ve just run out of time. So thank you very much.