Hip & Knee Surgery – Ask The Experts

Blog Health News 13th March 2024 Enquiries & appointments

Mr Paul Gill and Mr Syed Ahmed answer questions about hip & knee surgery that were submitted to us on Facebook.

Question: I had my left knee replaced last November by Mr Gill, all went very well. My right knee has now started to give me pain after prolonged walking. Is this common and should I consider having my right knee replaced?

Well the answer depends on many things. It depends if your pain is due to underlying osteoarthritis, depends on the degree of osteoarthritis, and it depends on the degree of your symptoms. So, whether your right knee needs replacing would involve having the appropriate consultation; taking your history, examining your knee and getting some imaging, and then determining exactly what the cause of your pain is. Only then could we really determine whether a knee replacement is suitable.

It’s certainly possible and we do see it that if someone’s had a knee replacement on one side within a few years it’s certainly possible that the other knee could become equally worn out and symptomatic and may need a similar procedure.

Question: Is it possible to have a knee replacement if overweight?

The simple answer to that is yes, you can have a knee replacement if you’re overweight and the outcomes are very good. Having said that it does depend on what degree of overweight. We have different categories in the form of you can simply be overweight and we base this on a body mass index. Once you get to 30 or above, that’s classified as clinically obese and even patients who are clinically obese can have very good outcomes with knee replacement.

So only when we get to the upper limits of obesity, which is a body mass index of 40 or above and this is classified as morbid obesity it’s been demonstrated that there’s a significant increase in complication rate and increased risk of early failure rate in the prosthesis and therefore patients at this level of obesity we encouraged to lose weight prior to considering knee replacement surgery.

As with anyone considering a joint replacement, if they’re overweight it’s always best to try and control your weight and reduce it and increase level of activity first because this can actually improve symptoms in itself and may defer the need for joint replacement so it’s always a good thing to think about first.

Question: Is partial knee replacement surgery an option? What are the positives? What are the negatives?

Increasingly, we’re doing more partial knee replacements rather than full knee replacements if appropriate. Not everyone is suitable for partial knee replacement and it’s estimated that maybe 20-30% of patients with arthritic knees are suitable for a partial. Those people have to have well localised arthritis just on one side of the joint and good preservation of the rest of the joint and if they do so then a partial knee replacement is an option.

There are a number of positives with partial over total knee replacement. First of all it’s a smaller procedure and you can have quicker recovery. The range of movement and function has been shown to be slightly better with a partial than a full knee replacement and people tend to walk with a longer stride length, and ascend and descend stairs more easily.
The complications and risks are also lower. The downsides of a partial knee replacement is that the redo rate is slightly higher but only very slightly. If we look at partial knee replacements compared to total new replacements at 10 years, then the survival of a partial new replacement is about 94% based on our national joint registry. The survival of a total knee replacement is 96%, so there’s a couple of percentage points difference at 10 years.

Whether you’re suitable for a partial knee replacement really would depend on the assessment by your surgeon based on his examination, your symptoms and the imaging that’s required.

Question: Apart from full knee replacement, is there an alternative procedure for osteoarthritis of the knee?

As with anyone with an arthritic knee, a full knee replacement usually comes towards the end of our treatment ladder. The first thing we’d always always do is try and encourage people to undertake regular exercise, weight loss. There’s an option of taking supplements such as glucosamine chondroitin, and to wear appropriate footwear and a lot of arthritic knees can be managed conservatively.

After this, There are certain injections which may or may not not help but certainly in the younger patient may be an option if we want to try and defer knee replacement. Then once we’ve got to the stage where someone has advanced osteoarthritis, there are more limited options and certainly a total knee replacement is the most common surgical option.

There are however other options including a partial knee replacement, which is suitable for 20-30% of patients with arthritic knees, particularly if the pain is and the arthritis is well localised over one aspect of the joint. There are other factors involved such as intact ligaments, but this could be discussed with your surgeon.

In younger patients there are other potential options including a procedure called an osteotomy, where we can realign the leg and offload the arthritic aspect of the joint and try and defer the need for knee replacement for some years to come.

Question: I had a total knee replacement a year ago. Now I have a knocking noise from that knee. Is it normal?

Well the answer is it can be normal. Many people, if not all patients, who have a total knee replacement or even a partial knee replacement can be aware of a certain clicking noise within the joint. That’s partly because of the joint surfaces involved.

In a normal joint you have quite soft articular cartilage which cushions well and it has a soft impact when mobilising or walking and you don’t hear a clicking necessarily. In a knee replacement you’ve got metal on plastic, so patients can be aware of a slight clicking sound when they mobilise particularly on certain activities. Having said that, if you have a knocking noise that is new, a year or so down the line, it can occasionally be related to loosening of the component so it’s probably something worth getting checked out but in the vast majority of cases it’s quite normal and nothing to worry about.

Question: Must a female patient have a catheter for knee surgery?

Well generally speaking the answer to that is no. Having said that, the majority of patients undergoing knee replacement surgery have it done under what’s called a spinal anaesthetic (a bit like an epidural), so it’s local anaesthetic at the base of the spine. For some patients that can affect their bladder function for a more prolonged period after the surgery and so occasionally a catheter may be required temporarily. Although this tends to affect men more often than women so it’s unusual for a female patient to require a catheter after knee replacement surgery.

Question: How long does it normally take to recover from knee replacement surgery? What things should I not do with a replacement knee? I’ve been told you should not kneel down.

It depends what you mean by recovering from a knee replacement. The final recovery actually takes up to a year in the sense you will continue to improve following the replacement surgery for certainly up to 12 months. A lot of the studies have shown that when patients have been asked how long it takes them before they’ve gotten as good as they’re going to be the rep is often about a year. Having said that, you’ll recover much more quickly in the early weeks and then continue to improve over a longer period of time. For instance, you normally only in hospital for a couple of days. Usually by 6 weeks people are not using a walking aid and have pretty much stopped taking painkillers. They may even consider going back to work if they’re of working age.

Following knee replacement, there are no specific things that we discourage people from doing. We want you to live an active lifestyle. Now the specific question is that you’ve been asked whether you should not kneel – well you’re allowed to kneel, I wouldn’t discourage you from kneeling but it is true to say that many people find it’s uncomfortable because the surgical scar lies at the front of the knee. I certainly wouldn’t kneel in the first 12 weeks because it’ be quite sensitive, but after that, particularly if you kneel on a pad or a cushion, many people find it’s perfectly comfortable to do so and I have no concerns about that with regard to damaging the underlying knee replacement.

Question: How many knee replacement operations go wrong? I desperately need knee Replacements but I’m too scared to risk the operation?

I can reassure you that the risk of a knee replacement surgery going wrong is extremely small. There are potential risks as in all operations and there’s a big list even with knee replacements; infection, thrombosis, bleeding.

The main potential risk with knee replacement is actually stiffness; loss of range of movement after knee replacement. It’s very important you do all the exercises after to try and reduce the risk of these other things, such as damage to nerves, vessels, ligaments, tendons, fractures which are extremely rare. One major potential complication that can be classified as a knee replacement going wrong would be deep infection. Now the risk of knee replacement is less than 1%, so it’s extremely small and overwhelmingly the likelihood is that you would have a very successful knee replacement with a good long-term outcome.

Question: What’s the best way to prepare for a total knee replacement operation? Exercise bike, Swimming or resting?

All of the above. Certainly it’s been shown that those people who undertake regular exercise prior to knee replacement tend to have a better outcome after knee replacement. So obviously the person has a painful knee so the level of activity is going to be limited to an extent, but certainly as you’ve mentioned in the question low impact exercise including cycling and swimming should be encouraged prior to near replacement. Obviously a degree of rest after exercise is important too but I would encourage people to remain as active as possible prior to undergoing the replacement surgery which should enhance their recovery.

Question: I am 50 years old, I have had a left knee problem since I was 25. I had multiple surgeries including arthroscopies and microfracture. I was told about 8 years ago privately that I needed a new kneecap but I was too young. Now I’ve been seen on the NHS and told kneecap surgery not offered, just total knee replacement. Do you offer partial knee replacement with just the new kneecap? What are the success rates of this surgery compared to a whole new knee?

Yes, partial knee replacement is available and is suitable for some people. A partial knee replacement just involving the kneecap or the patella is an uncommon operation but we do do it in certain situations. So if your osteoarthritis is localised just to the patella part of your knee, and the rest of the knee is in good condition, particularly as you’re only 50 years old and very young for knee replacement, if your symptoms are particularly debilitating then a partial knee replacement is certainly an option.

What are the success rates of this compared to a full knee replacement? Well it is true to say that the survival of a partial knee replacement is not as long as a total new placement, but bearing in mind to your young age it is still a potentially good option. Even if a partial knee replacement lasts 10 years, you would then be 60 and then be in a much better age group to be considered for a total knee replacement. Conversion of a partial to a total in this situation is relatively straightforward, so it is certainly an option and you need to discuss that with a surgeon who undertakes partial knee replacements of which there are now quite a number.

Question: I am 63 years old and was told I needed a knee replace placement about 10 years ago. I’ve managed with PRP injections, then steroid injections, but the most recent injections only lasted 10 months and the pain has returned. My knee has hopefully remained in the same condition for the last 10 years as I don’t ski anymore or play sports as I did. My passion now is horse riding and I’m concerned about returning to my horses after surgery. How long before I could get back to my hobby and would I have any restrictions?

The likelihood, even though you’ve been less active over the last 10 years, is that the underlying osteoarthritis has progressed and as you found out the injections will become increasingly less effective, such that you may well be a candidate for a knee replacement.

Following knee replacement we actually want people to live an active lifestyle, so certainly if your concern is about riding horses then I would encourage you to return to horse riding after knee replacement surgery. I think it’s a great form of exercise. I have a number of patients over the years who’ve undertaken regular horse riding and generally speaking they’re back on their horse to some extent by about six weeks which may seem quite early but if you’re just sitting on the horse and walking then that’s a reasonable thing to do. Certainly by 12 weeks I’d say you’d be back to trotting, and obviously cantering maybe a little bit later. That’s sort of an idea of where you could be and in the long term there’s no reason why you shouldn’t be able to ro ride horses at a good level, so I wouldn’t be overly concerned about that.

Question: I have Mobility problems. I’ve had my left knee replaced but not entirely successful. Stairs are a problem. My knee is now playing up and I have pain in both knees when sitting for long periods of time. Also at times my right knee keeps me awake at night. Do you think it’s time for me to have my right knee replaced?

It really depends. It’s certainly possible if your right knee is giving you increasing pain, it’s limiting your activity; walking stairs and waking you up at night. This may well be due to progression of the underlying osteoarthritis for which a knee replacement may be appropriate.

I’m sorry to hear that your left knee replacement is not entirely successful but stairs can be a problem for people with knee replacement. It puts a lot of stress on the knee and people can find it difficult. However, the majority of patients do very well and can manage stairs perfectly well. There’s a small possibility with regard to your left knee replacement that the patella may be an ongoing problem. In many cases it is not routinely replaced as part of the knee replacement and in a very small percentage of people can develop arthritis in that aspect of the joint and cause problems later on, particularly on stairs. So it would be worthwhile having that looked into because occasionally there are things that can be done about it.

What are the benefits of robotic knee replacement?

It’s important to note that this is a robotic assisted knee replacement, so it’s normally the robot there to assist an experienced surgeon who’s undertaking your knee replacement. The main advantages are that patients can have an accurate CT scan prior to the operation, and all the anatomical landmarks can be put into the computer and the robot prior to considering surgery. During surgery this allows me to make more accurate cuts and hopefully a more balanced and better fitting knee replacement. These changes are relatively small but there is some evidence that it does reduce the risk of making incorrect cuts during the time of surgery, because during real time we can assess both the balance and the level of the cuts by using the robot and overall better long-term outcomes.

Question: I’ve had an X-ray which shows that I need a new left hip. I’ve also had a DEXA scan, which shows osteopenia, particularly in the femur and the hip. Will this diagnosis make an operation difficult?

No, it wouldn’t. The X-ray certainly confirms that there’s wear and tear in the joint and the space between the ball and socket is now lost, because of a worn out cartilage. The DEXA bone scan looks at bone density and this gives one the diagnosis of osteopenia or osteoporosis.

Broadly speaking, we have two types of hip replacement: cemented and uncemented. In patients who have good bone quality and good potential to have bone in growth and on growth, I would use an uncemented hip replacement. However, with someone who’s been diagnosed with osteopenia osteoporosis, where the bone density has now been lost, I would tend to use a cemented implant. Therefore I’m not relying on the bone to grow into the new hip replacement implant.

Question: Can I do anything before my hip replacement surgery to help aid recovery?

There are a number of things that one can do to make sure that they recover quickly following a hip replacement or a knee replacement. One of the first things I tell my patients is to make sure they take regular painkillers when they suffer from arthritis. So a lot of people believe that the painkillers mask the pain, but we know what’s causing the pain so there’s no reason to suffer in pain. so I’d rather you take simple painkillers, such as paracetamol, and anti-inflammatory, such as ibuprofen if you can and continue to stay active.

The first thing that you should do is really make sure that you’re walking and taking pain killers to help you walk the normal distances that you’re used to walking. Then simple stretching and conditioning exercises to work on the muscles around the hip and this is something that a physiotherapist can guide you with. Exercises, especially in the pool, such as aqua aerobics do help because they make it easier to move your joint especially when it’s arthritic. so carrying on staying active and doing simple exercises will help keep the muscle muscles conditioned so you can recover quicker following a hip replacement.

Question: I’m 68 years of age and I’ve always had an active Sports background with football badminton and now golf I suffer with pain in my right hip joint. Is there a way of telling if my hip joint is worn and causing the pain? I’m able to walk quite happily around the golf course but do start to limp after a while. I certainly can’t play badminton due to the pain it causes.

Hip joint pain is usually pain that is in the groin. Pain on the outside of the hip or pain around the buttock likely comes from muscles or potentially from the lower lumbar spine. Therefore, if you experience groin pain on walking short distances, or doing any sort of activity, then this likely comes from your hip joint.

The only way of really diagnosing if you have arthritis in the hip is by getting an x-ray of the hip. The X-ray of the hip will show the surgeon that you’ve lost the space between the ball and the socket as a result of a worn cartilage, and then you’ve got bone grinding against bone which will cause the pain.

With modern implants and the bearing surfaces that we have, one could definitely go back to playing more Sports following having had a hip replacement.

Question: I have a BMI of 32 and type 2 diabetes. Can I still have a hip replacement?

Yes but with any surgery there’s an increased risk. With type 2 diabetes and a high BMI these complications are slightly higher, especially with type 2 diabetes and poorly controlled diabetes. What we’re concerned about is infection and therefore we monitor this with not only your blood sugar levels but also with hba1c, which shows us a long-term good controlled blood sugar level. As long as your hba1c is well controlled there’s no reason why you won’t be a good candidate for surgery.

With a high BMI the first thing you want to do is try methods to try and lose weight and have a good diet. This will help with diabetes too and certainly that improves the outcomes that you can have following joint replacement surgery.

Question: My husband is 40 and is having a hip replacement next week. Do you have any advice for recovery and recuperation? We have two small children who leave toys all over the house so I’m a bit nervous.

Following having had a hip replacement and especially after a minimally invasive hip replacement, I will show you that you can walk independently after surgery. But in the first couple of weeks, in order to aid recovery and let the muscles heal and the wound itself heal I suggest that you use your crutches.

After two weeks, you’ll start losing the crutches slowly. Initially you will walk independently in the house and then you start walking independently outdoors. The Physiotherapist who will see you following the procedure will give you a list of exercises that you can perform following surgery and they’ll also give you exercises that you can perform week on week. This will slowly work on the abductors, the flexors around the hip and will certainly help you by a six- week mark to get back to pretty much all normal activities.

You do want to avoid hazards around the house which could potentially lead to someone tripping and falling after hip replacement surgery because there’s an increased risk of fracture or dislocation. You want to try and avoid that happening until all the muscles and tendons around the hip have completely healed.

Question: How long after my hip replacement until I can walk and go back to the gym? Will any exercises help me recover faster?

You should really be able to walk independently straight after surgery, but using your crutches gives the muscle some time to heal and it’s certainly not a failure on your part not to be able to walk independently. Over the course of the first two weeks you can slowly start losing the crutches.

The physiotherapist will give you the exercises that you need to do but after six weeks, what I tell most of my patients is to do simple close circuit exercises which is using stationary a bike, or using a cross trainer. Avoid anything with impact initially at least and that helps the right muscles heal with little impact.

Question: Will I need to adapt anything in my home beforehand to help with recovery post surgery?

There’s simple things that you can do which will probably help. One of them is to make sure that you have someone deliver groceries to you initially after the hip replacement because you’re not going to be able to go out much. If you have someone who can help you with cooking so you avoid standing for long hours in the kitchen. In terms of the toilet you can get some toilet seat raises but most of the time this is not necessary. It may be difficult to sit on a low sofa immediately following surgery so you may well want to have a higher seating arrangement. Make sure that you have no hazards around your bed so you can get in and out of the bed comfortably but no massive changes required in your house.

Question: Are you able to perform a hip placement without being put under general anaesthetic?

Yes, 90% of hip replacements that I do are actually under a spinal anaesthetic with a bit of sedation. Spinal anaesthetic is very similar to an epidural, it involves an injection at the bottom of your spine and it numbs you from the waist down. That stays in effect for the next two to three hours, until you’ve had a hip replacement and you’re and you’re back onto the ward. You can then choose if they want to have a bit of sedation which means that you’re put in a deep sleep, or if you want to stay awake and hear what’s happening during the procedure. Most patients choose to have a bit of sedation so they wake up in recovery after the procedure has been done.

With a spinal anaesthetic there’s no sensation of power in the lower limbs for about 3 hours following the procedure and things slowly start waking up and when you can start moving your ankle up and down, or lifting your foot off the bed, you can then attempt to get up, and walk with the help of a walker frame and the Physiotherapist.

Question: Why do some patients only have a partial hip replacement?

Unlike knees, there’s no real partial hip replacement for an arthritic hip. A hemiarthroplasty, which is half a hip replacement, is done for patients who are frail and who end up in the hospital with a femoral neck fracture which is a hip fracture. So in a situation where someone’s broken the ball part of the hip off the stem part, they offered a hemiarthroplasty which is half a hip replacement essentially as an emergency procedure.

Question: What is a minimally invasive hip replacement?

A minimally invasive hip replacement, the wound is slightly smaller (about 6 to 8 cm) and what we do is we don’t disturb any of the muscles going into the hip. I split the muscle fibres and take one or two tendons down, which I repair at the end and this gives me enough access to visualise the arthritic hip, and then to put the new hip in.

We have special instruments which help me retract and allow me to do the hip replacement. What this allows is for the patient to get up and walk on the same day or the next day after surgery and generally patients pain scores are lower. You’re back to doing most normal activities a lot earlier than with conventional hip replacements.

Question: What is a robotic joint replacement and what are the advantages to a conventional joint replacement?

Conventional surgery, the surgeons rely on jigs and instruments and landmarks in the surgical field. With robotic joint replacements, patients have a CT scan pre-operatively which helps identify certain landmarks which we give the robot during the surgery. We use these landmarks to then put, for example, a hip replacement in the right place, and you get live information as to the degree to which you are putting the cups in with the help of the robot.

The surgeon’s very much still in control and deciding where to put the implant. It’s not that the robot’s performing the surgery, but it helps navigate intraoperatively exactly where to put the implants. Overall there’s an increased amount of accuracy with which you can plan the surgery and then execute the surgery.

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