Knee Osteoarthritis: What You Need To Know
With Professor Brian Devitt

I’m going to speak about Knee Osteoarthritis and what you need to know. I always like using a picture of a patient. This is a lady who I performed a knee replacement on in Australia and this is 18 months following her knee replacement on a charity walk to Vietnam and she was able to manage the steep inclines with her new knee. This is one of the successful patients who I have performed a knee replacement on and the vast majority of people do very well following a knee replacement.

When we were in Vietnam I also came across a number of quotes from Confucius who was a Chinese Philosopher and this is one of my favourites, “It doesn’t matter how slow you go as long as you do not stop” and I think its particularly relevant when dealing with Knee Osteoarthritis.

My children always say to me, “Tell me something I don’t know” and the purpose of this educational even6t is to inform you about Knee Osteoarthritis.

Initially we are going to talk about the basics What is Osteoarthritis? What treatment works best? We also want to talk about the evolution of surgery which is quite interesting and what does the future hold? Most people say Knee Osteoarthritis is just a bit of wear and tear and it can be but it can also be an awful lot worse. Try telling this patient that this severe arthritis is just a bit of wear and tear. There is a lot of bony debris in this patient’s right knee even though the patient was complaining about his left knee being his sore knee.

People come in all shapes and sizes and when we see people with Osteoarthritis we see 3 main varieties of the appearance of someone’s legs. First, is the normal variety and that is just the straight leg. You can see someone with a bow leg which is what we describe as Varus or there can be people with Knock knees which we describe as Valgus. These all have different patterns of wear and that is for us to know as surgeons and you can often distinguish where the arthritis is going to be based on the shape of the patient’s legs.

What treatment works? Many patients come in and we have to be careful about what treatment we recommend because we want the one that will work the best for that patient. There has been a lot of studies on this topic and as you can see in the chart here these are all conservative treatments. Physical activity is very important and it is really important to maintain.

Weight loss is probably the most effective means of reducing pain from arthritis and I will discuss this a little bit more later.

Acupuncture hasn’t shown to be very effective.

Massages can be somewhat effective as we can massage the muscles if they have become tight above or below the knee which can cause pain.

Braces can sometimes be effective in early arthritis. Insoles, likewise, can be somewhat effective as they can offload the side of the knee that can cause trouble.

Glucosamine based on these studies have said it is not effective but it is a very inexpensive medication, even if it has a placebo effect it may help someone.

I’m going to bring you back to talk a little bit about physics. One of the things that helps arthritis is weight loss so we will do a little bit of maths. If you are just walking normally twice your bodyweight goes through your knee at each step. If you are walking downhill then up to 4 times your bodyweight goes through your knee. If your running then up to 8 times your bodyweight goes through your knee. If we do a bit of calculation and get a 100kg male who may be slightly over weight when he walks downhill there is 400kg going through his knee. If you were considering running that’s 800kg going through the knee that’s just shy of a ton. If a person loses 10kg that’s 10% of his body weight which would be 40kg per knee per step when walking downhill.

We also recognise that exercise is important and we recognise that trying to do exercise that doesn’t exacerbate your knee pain is really critical in the early stages so the likes of Pilates is good or low load exercise like cycling or swimming can be very effective to improve the strength of the leg and reduce the pain within your leg.

Pharmacological Treatment then, Anti-inflammatory medication is effective and the reason it is effective is because it reduces the swelling in the knee. When you have swelling in your knee you tend to shut down muscles around your knee so they stop working as shock absorbers and when the muscles stop working then you tend to get much more impact particularly when walking down stairs.

Steroid injection can be helpful especially if someone has swelling or inflammation within their knee and its normally done within the early period.

Hyaluronic acid by these studies has not been found to be effective in isolation but we tend to combine it now with steroid and that can be a little bit more effective.

Platelet Rich Plasma can be effective in certain places particularly in the early arthritis cases.

Now we will look at surgical treatment and that’s what most people come to me for. Arthroscopic Washout, in the past I used to call it the ‘wash and go’ you used to come in and get an arthroscopy wash out some of the debris and go home but we realised that is not effective as it does not address the arthritis issue and now we try to avoid that as best we can. We can look at Arthroscopic Meniscectomy so taking away the meniscus. Now in the setting of arthritis if you have a meniscal tear we wouldn’t do an Arthroscopic Meniscectomy but if you have very early arthritis and there is a meniscal tear which has flipped or is causing mechanical symptoms then that may be appropriate but it is done on a case to case basis.

We also look at Osteotomy and that is where we adjust the alignment of a person’s leg to offload the side of the knee that’s worn and that can be effective in some cases but it is usually in young patients presenting with arthritis. Joint replacement which we will discuss a bit further is a very successful surgery in the right setting at the right time.

I’m just going to discuss some knee replacements now and there are various different ways to do knee replacements and what we found over the past is that we have knee replacements that can use specific implants. We can get a patient’s knee and we can take a CT of that knee and use these cutting blocks to give a specific cut for that individual. They have been found to be reasonably successful but no more successful than a high-volume surgeon doing routine knee replacements so it is important that we do not get carried away.

We now will look at robotic surgery and that has seen a huge researches particularly in the USA and the robot uses something that we call navigation so we can plot that persons knee in space we can also do a CT scan before hand and what it allows us to do is do very accurate cuts with this robotic arm and its assisted surgery but in the long run it is no more effective than a surgeon how carries out many surgeries and has a lot of experience so we wont get carried away too much but there is certainly a place for robotics in knee replacement surgery.

We are going to look at the suppliers of our implants that we put in our patients and each of these companies have their own robotic offering and its important that the surgeon you go to that first of all they are an experienced surgeon and if they offer robotics or not it is really incidental. I think that they want to be a high-volume surgeon which is really important.

I’m going to give you a few case examples now, this is an example of what we would do when a patient comes in to see us and we get a weight bearing x-ray of their knees. Here on the right knee you can see that the space between the Femur and the Tibia is nicely preserved on the outside and very diminished on the inside and we can see that on both sides so this person would likely have slightly bow-legged deformity so we know they have arthritis within the region of the inside of the knee.

We look at the knee from the side as well and we see that the space between the knee cap and the front of the knee is slightly tight so they have arthritis in not just the inside of the knee but also on the front of the kneecap but we always would address the patient’s symptoms and where they are having pain in that knee. We look at this persons MRI scan we look at it from the front of the knee and we can see the presence of whiteness which indicates fluid within the knee but if we look at the inside here we see whiteness of the bone which indicates that bone is under severe stress within the knee and that is where the site of the patient’s pain is.

Often x-rays are sufficient but sometimes we take an MRI as it can be effective in looking further into the knee to get a better idea of what is going on and that person has likely had just that side of the knee replaced.

This is another example of a patient of mine who presents with severe pain on the outside of the knee and it is a slightly different configuration of what we saw. We see that the space on the outside is largely reduced compared to the space on the inside and the nice thing about having both of these x-rays is that we can compare both sides so we see the outside of the knee on the left is nice and preserved where as on the right it is reduced and you see the extra bone has formed and this is where the arthritis exists.

In this patient you can see they have arthritis under the knee cap as well so of the 3 compartments in your knee the inside, the outside and the front of your knee all of the 3 parts are affected so this person is likely to have a Total Knee Replacement as opposed to a Partial Knee Replacement on just the affected side. As you can see this is what this lady had and she has a nicely balanced knee, so it looks a lot like the other knee and this is the joint replacement I was using when I took these x-rays in Australia and you can se it from the side where we have resurfaced the knee in addition to the Total Knee Replacement this lady went on to do very well after surgery. Once again, we go back to that x-ray of the isolated arthritis on the inside of the knee and what we do now is something called a Partial Knee Replacement so we just replace the inside of the knee as that was the part that was affected.

We mentioned about robotics and the role that robotics might have in joint replacement and it is important to be aware of it. This is a slightly older picture of my extended family and this was taken in 1922 and I have a massive interest in what the future holds because my future probably holds a joint replacement for me.

This is my grandfather back in the day and you can notice he is not wearing any shoes like all of his brothers. My grandad had a hip replacement and his 2 other brothers had a hip replacement. This allows us to realise that there is genetics to arthritis and unfortunately we can’t change our genetics but it is important to know that this is what the future holds to be able to look and tell people who are at risk of developing arthritis and maybe in some way mitigate the development of arthritis in those individuals but I think the key is to maintain your body weight and I think that is something we all have some choice over and I think that is really key if you have a high risk of developing arthritis it allows us to look after ourselves with age but we are not quite there yet in terms of the genetics of arthritis.

What we do know is that exercise is very important and we are getting smarter by using these smart fabrics and being able to identify which muscle groups are weak and the future holds being able to look or tailor rehabilitation to further advance our ability to postpone the inevitable joint replacement for some people and looking how we can fully maximise rehabilitation.

We are about to embark on a joint lab where we look at patients with arthritis pre and post joint replacement to see if we can identify the muscle groups in which they were weak in and I think this will make great advancements in terms of how we manage patients going forward but we use all of these smart fabrics and technologies in years to come.

People always ask us about stem cell therapy for knee arthritis and I think it is really important because we all look for the next best panacea when treating arthritis and most people are weary and for good reason undergoing joint replacement because you can’t go back on it so they look for other lesser modalities but unfortunately the literature is just not there in terms of the use of stem cells. In fact, if you look at what the experts say from Australia where I was working for 10 years that the position statement is saying that the use of stem cells is very complex and that really, we don’t understand the effectiveness in arthritis but they also say that they would not support the evidence to use stem cell treatment as a clinical intervention and outside a clinical trial setting.

A lot of people who heddle the use of stem cells for treating Osteoarthritis are not doing it as part of a clinical trial setting it is for monetary gain only so its important to be a little bit circumspect about those scenarios but I think there is potential there but we have to do it in the setting of clinical trials firstly.

I’m going to finish now with another quote from Confucius and he said “Choose a job you love and you will never have to work a day in your life” and we as orthopaedics have a great job because we give people back their mobility, we give them a new lease on life but its very important that you only choose to have arthritis when you have exhausted non-operative means, when you have gone through the effect of non-operative measures and then get to the point of a joint replacement because you will do much better at that point from a rehabilitation perspective

Yes, I do carry out Partial Knee Replacements and increasingly more frequently than I used to and the reason for that is people tend to do very well with Partial Knee Replacements and do have a slightly quicker recovery.

The prosthesis typically lasts 15 years and what normally happens is that other parts of the joint tend to wear out. It is a relatively easy conversion from a Partial Knee Replacement to a Total Knee Replacement.

In terms of recovery, patients tend to have quite a quick recovery following Partial Knee Replacements, so they normally walk a bit quicker with less pain and in terms of getting back to their normal activities, it varies from anywhere between 3 months and six months.

Knee sleeves essentially are sleeve you pull over your knee so they provide compression to your knee so they are effective and they give a bit of feedback to your knee when you have swelling. They don’t necessarily reduce swelling but they do give a little bit of support to your knee.

When you have bone on bone arthritis they are probably less effective. Typically, patients with bone on bone arthritis complain of a dull, aching pain in their knee so it will provide a little bit of support but I don’t think it will eradicate the pain entirely.

It is very interesting, its an area which I’ve looked into quite a lot and I used a lot of robotic surgery when I was in Australia and since I have come home I have reverted back to manual surgery and the outcomes are the same. I think robotics are the future but we don’t have any compelling evidence to suggest that the outcomes following robotics surgery are any better than any surgeons who carry out high volume knee replacement, that means they do a lot of replacements but I think as we evolve and the next generation of robotics surgery comes in I think it will improve things and we will have better results in the future. For now, if I was choosing, I’d choose a high-volume surgeon and not a surgeon that does robotic surgery for having a knee replacement.

There are a variety of symptoms you can have, I suppose you should look at the age of the individual. Typically, patients who are towards their middle ages and elderly patients are more likely to develop arthritis they usually present with pain so pain at rest or pain at night is one of the hallmarks of arthritis.

In terms of symptoms you tend to have people who have decreased range of motion within their joints that is another main symptom and you also see deformity particularly in knees when arthritis gets worse but it tends to be based on symptoms so if someone is in pain or has stiffness and swelling in a joint

It’s very interesting because I think road running is a bit of a myth of a cause of arthritis and if you look at the typical body of a runner or certainly a marathon runner they are quite skinny people normally so they tend to have lower bodyweight and therefore they are less likely to develop arthritis but there was a really interesting study carried out a few years ago that I had to review which looked at the evidence of arthritis within a group of marathon runners and found it was actually lower than that of the normal population.

What people always often blame running because they often revert to running in their 40’s and 50’s but they probably played more rigorous sports in their early life and that’s where they took a chunk out of their cartilage and the running just caused the end result or just exacerbated it but people who are active and have a low body weight tend to have less arthritis than people who are over weight and more sedentary

It is mentioned in my talk a very simple equation of how much body weight goes through your knee when you walk so obesity is a big factor and loosing weight is the best non-operative treatment for arthritis. Whether there is a metabolic factor or not I’m not so sure if that’s proven but certainly weight is a huge factor.

Whether it is unilateral or bilateral you can kneel after any knee replacement, it does feel a bit strange when we typically make an incision we make it through the front of the knee and therefore there’s slight numbness on the outside of the incision so it feels a bit odd when you kneel down. There’s no reason you can’t kneel on your knee but it just feels a bit strange.

Ironically, when you have bilateral knee replacements they both feel the same so it doesn’t feel as odd, one doesn’t feel different to the other but someone gave a nice analogy it’s like wearing a pair of sandals at the start of the summer they chafe and feel a little bit unusual on your feet but as your skin hardens up your able to manage without any problems so there is no contraindication to kneeling after any knee replacement.

It depends on how bad your symptoms are and we often have people coming in and saying I’m better off having it when I’m young rather than having it when I’m old and it would be easier to recover but you need a knee replacement when you need it and when you start having pain at night, when you’ve pain at rest, when it affects your quality of life and I say to patients as if it’s the last thing you think about before you go to bed, if you can’t sleep at night and it’s the first thing you think about in the morning because you have pain in your joint you probably need a joint replacement so I think based on that then that’s really my answer.

We are very selective about the patients we choose to do bilateral knee replacements on so they have to have evidence of pain and arthritis in both joints and typically they are as bad as each other.

The advantages to having them both done are you reduce your rehabilitation time and you’re up and running straight away you don’t have to go back and have the second one done.

The disadvantages are that it’s a bigger undertaking and as I joke to the patients you don’t have a good leg to stand on so it can be a bit more challenging in the early period of rehabilitation, the risks are slightly higher but they’re not significantly higher nowadays because we have refine dour surgery and it’s a fairly quick operation so doing the both together under the same anaesthesia so really it is on a case by case basis but patients who have profound arthritis and have really a really decreased range of motion tend to do very well when they have bilateral knee replacement done because they can move both legs the same

It depends on what age the patient is and what the indication was for the arthroscopy but we often find people who have had a meniscectomy or had some of the soft tissue cartilage removed from their knee and if they’ve done it twice that would suggest that they have had some ongoing issues with that knee.

What typically happens in them situations are the hard cartilage of the knee tends to wear out and really in those situations we’d investigate with weightbearing x-rays or potentially an MRI to see if the joint has worn out. If the patient is young and it’s relatively isolated to one joint then they may be a candidate for a partial knee replacement but it’s done on an assessment and where the pain is in particular.

I think with any individual like that you can get post-traumatic arthritis and that unfortunately afflicts younger people all of the time so we would always be hesitant to go to a knee replacement unless we absolutely had to.

The same principles apply here as I mentioned in my talk by maximising non-operative measures such as body weight, occasional anti-inflammatory medication, maintaining the strength of the knee is really important. If they’re not settling with oral anti-inflammatory medication one could consider an injection of local anaesthetic and steroid or maybe hyaluronic acid can be effective in some cases.

If it is a traumatic case with metal work in place and they are heading for a knee replacement sometimes even just removing the metal work can improve some of their symptoms and that would be necessary before a joint replacement and indeed advisable before a joint replacement so that might be a temporising measure to help the person along the way but we try to do everything to delay a knee replacement typically.

Those two examples are good because there is no contraindication to playing those sports.

I suppose if you look at sports that put a high level of load through your knees such as running or running marathons you wouldn’t really advise that after a Total Knee Replacement and potentially after a Partial Knee Replacement and nowadays were less strict about what we would consider contraindications for people to participate in.

When I was living and working in Australia lots of patients came in wanting to surf and that’s a fairly rigorous sports as you have to get very low. I’d say if they’re able to surf I obviously have no problem with them doing that but obviously everything comes with risks but we let people participate in sports because it’s good for them

No, it’s not and I think that’s where we are very particular in terms of choosing patients that are at the right time for a knee replacement and I think one of the important things we spend a long time talking to people about is informed consent and as part of informed consent we have to explain the alternative options and I’ve mentioned them in my talk but also the risks related to surgery which is really important so one of the things I’d explain to patients is that we are paranoid about infection and infection occurs in less than 1% of patients but we try to do everything that we can to avoid that.

The other thing which people complain of after knee replacement is stiffness and we find that patients have to really engage in the rehabilitation if they don’t get engaged or they have too much pain and they can’t engage then they do become stiff and that can be a pretty miserable experience for the patient so we try to do everything that we can to mitigate the risk of complications but unfortunately they do occur but when they do occur we tend to treat them very aggressively and very early.