Everything You Need to Know About Knee Replacements

Hello and welcome back to the ThreeSpires Physiotherapy blog where we take a look at all things physiotherapy and health related. This blog is a natural follow up to our very popular blog: Everything You Need to Know About Hip Replacements and takes an in-depth dive into knee replacements. Just to remind anyone first reading our website: we are a home visit physiotherapy service and all of our physiotherapists visit their patients at home. Our physios are mobile and come out to you at a time and place of your choice.

So, what is the first thing you need to know about a knee replacement. Well it’s probably a good idea to start with some anatomy first.

What is the Knee?

A pretty simple question and at first glance it seems obvious that it is the joint in the middle of the leg but in reality it is quite a complex joint and to understand why someone has a knee replacement and what will be affected by this it is necessary to have a reasonable idea of the anatomy of the knee joint. The knee is made up of the femur (large thigh bone), the tibia (shin bone) and patella (knee cap) and is in fact two joints all in one! The first and most obvious part is the hinge joint between the femur and the tibia itself, this is the load bearing and probably most important part of the knee. Inside of the knee there is cartilage which provides shock absorption and allows the bones to move each other easily and there are also two semi-circular discs called the menisci which are also important for joint health. Moving over the outside and front of the knee we have the patella (knee cap) and the patella-femoral joint and underneath the patella we have more articular cartilage which allows the patella to glide freely.

What is a Knee Replacement?

Knee replacement is major surgery where the ends of the femur and tibia that are damaged or worn are replaced with artificial components of metal, ceramic, or plastic. The operation aims to reduce pain and restore the natural function of the knee joint. There are two main types of knee replacement surgery that you should be aware of:

1. Total Knee Replacement (TKR): In a total knee replacement, the ends of the femur and tibia are cut away and replaced with prosthetic components. The kneecap is often left unaltered and put back into place. Sometimes the surgeon will resurface the underneath of the patella if there is significant arthritis there.
2. Partial Knee Replacement (Uni-Compartmental): In this procedure, only one side of the joint is replaced – for example the medial (part of the joint closest to the midline of your body) is replaced but the lateral (outside) part of the joint is left unaltered.

Which option you have will depend upon how severe the arthritis is in your knee and whether or not both sides are affected. If one side of the knee is unaffected by arthritis and is in good condition then it is likely that the surgeon will suggest a partial knee replacement as this will enable you to recover more quickly.

What are the Reasons for Having a Knee Replacement?

Having had a look at the anatomy of the knee and what a knee replacement consists of we now need to examine why someone may need to have a knee replacement.

1. Osteoarthritis of the knee: this is by a long way the most common reason for needing a knee replacement. Osteoarthritis as discussed in previous blog posts is the most common form of arthritis and is a degenerative joint disease that primarily affects the cartilage. This is the protective tissue covering the ends of bones in a joint. Osteoarthritis gradually develops over time and is often associated with aging, though it can also be caused by joint injuries, repetitive stress, or underlying joint abnormalities. In a healthy joint, cartilage acts as a cushion, providing a smooth surface for the bones to move against each other. In osteoarthritis, the cartilage gradually breaks down and wears away, leading to joint pain, stiffness, and reduced mobility. If the osteoarthritis is severe and causing symptoms such as pain and stiffness that are limiting function and quality of life then a knee replacement may be considered.
2. Rheumatoid Arthritis: this is a less common form of arthritis which can affect joints and cause them to degrade and wear over time. It can cause the integrity of the joint to fail and lead to the need for a knee replacement. If the rheumatoid arthritis is severe or left untreated this is likely to lead to the need for a joint replacement.
3. Trauma to the Knee: If you have a serious enough accident such as a high speed car accident, the knee joint can be damaged in such a way that it is necessary to replace the joint.

If you read our previous article on hip replacements you will notice that the list of causes for needing a hip replacement is much longer whereas in the knee it is (mostly) simply joint wear and tear caused by arthritis. Overall, knee replacement surgery is considered when conservative treatments such as medication, physiotherapy, or walking aids no longer provide adequate relief from pain and disability. It should be noted that although in the past it was recommended to wait as long as possible before having a knee replacement it is now considered better to have a joint replacement when it starts to affect function and quality of life. This way the patient maintains maximum strength and function in the joint before undergoing surgery.

 

Who Is Likely To Have A Knee Replacement?

Well, fairly obviously anyone with a knee could have a hip replacement but there are a range of factors that make having a knee replacement much more likely.

1. Age: unfortunately as with most things in life age is a factor and a reality of those people that are most likely to have a knee replacement is that they are likely to be older. This is for a number of reasons but the primary reason is that as we age arthritis becomes more common and our joints and the associated cartilage tends to wear making it more likely that the joint will need replacing.
2. Gender: Women are unfortunately (for them!) more likely to have a knee replacement, there are a few reasons for this. Firstly women tend to live a bit longer than men and therefore for the reasons above as we age we tend to be more likely to need a joint replacement. Being female also makes you more likely to have rheumatoid or osteoarthritis and therefore makes it more likely that an elderly female may need a knee replacement
3. Obese Individuals: although you might think that this seems obvious: i.e. the heavier you are the more load you put on your joints and the faster they are likely to wear out. This may be a part of the reason that obesity is linked to osteoarthritis but it is most likely not the most important factor. Research now supports the idea that because individuals who are obese have a high general level of inflammation in their body that this then worsens the inflammation in the joints and leads to arthritis.

Clearly as described earlier anyone with osteoarthritis or rheumatoid arthritis is also much more likely to need a knee replacement than anyone without.

What Is The Process For Having A Knee Replacement?

So now we understand what a knee replacement is, the reasons for needing a knee replacement and who is most likely to have a knee replacement we probably need to take a look at the overall process of having a knee replacement. Below is a general overview of a normal process:

1. Beginning to Have Pain: initially you will probably have begun at some point to notice that your knee feels stiff after walking or exercise and that if you do too much you get knee pain and need to sit down. You may also notice that your knee is sore and stiff first thing in the morning. Often people will persevere for a long period here, just thinking that it is a temporary strain and will use analgaesia and anti-inflammatories to manage their symptoms. Your knee may intermittently swell up at times as well in this period.
2. Initial GP Visit: after persevering for a while many people will visit their GP, who will initially (depending upon age and symptoms) most likely prescribe some stronger painkillers and tell them to see if their symptoms go away in a month or so.
3. Second GP Visit & X-Ray: if the pain does not improve at some point people usually return to their GP who will now most likely order an X-Ray of the knee to have a look at what is going on and to inform the best management options.
4. X-Ray Shows Osteoarthritis: at this point the GP will discuss with the patient their options and will probably refer them to physiotherapy. Some people will go straight to orthopaedics and for a surgical option but most people if their symptoms are not too bad and they are still functioning well will be offered physiotherapy.
5. Physiotherapy: the patient now has an assessment with a physiotherapist and discusses the results of their x-ray. The physio will give the patient a lot of advice and a program of strengthening exercises aimed at giving the patient a stronger leg and core that can better control their knee joint. For many patients this is successful and they improve and are able to manage their knee for a long time.
6. Pain Has Not Improved: not everyone improves with physio and some do but then their pain returns. If physiotherapy has not been successful and the patient is struggling a referral will be made to orthopaedics for a consultation with a surgeon.
7. Orthopaedics: here for the first time the patient will meet an orthopaedic consultant who will look at their x-ray and conduct an assessment. At this point many people will be offered a steroid injection to see if this will help manage things. However, if things are too severe or if the injection does not work then the surgeon will discuss a joint replacement.
8. Pre-Operative Assessment: before having your knee replacement you will need to attend a pre-op assessment. Here you will have an assessment by the doctors but you will also get vital information either in a booklet or sometimes in person from a physiotherapist. It is important that you read the booklet thoroughly or pay close attention what you are told by the physio because this will give you a large amount of key information about your joint replacement and recovery afterwards.
9. Operation Takes Place: at this point you come into hospital and undergo the procedure. Whether or not this takes place under full anaesthetic or just under a spinal block depends on your anaesthetist, your past medical history and at least to some extent your own preferences.

What Happens After My Knee Replacement Operation?

An obvious and pretty reasonable question that many people have is: what will happen immediately after my knee replacement? Well, this depends upon a few factors such as your age, past medical history, how well you come out of anaesthetic and whether or not you have any complications but below is a reasonably standard process for someone without too many complicating factors:

1. You wake up in a hospital bed: at some point after having your knee replaced and  you will likely wake up feeling pretty sore and fatigued. The nurses and healthcare assistants will come round to check you are okay and will take some observations such as oxygen saturation and blood pressure. You will also very likely be given some food and drink for the first time in a while. At this point pain may well not be too bad as you will still have some of the effects of the anaesthetic lingering in your system.
2. Pain Relief: fairly quickly once the anaesthetic has worn off your knee will start hurting and it is important that you get pain relief. Don’t think that you should be brave at this point. It is absolutely normal to need pain killers as you have just had a major operation.
3. The physios arrive: getting up and weightbearing as soon as possible is a key part of the process. Ideally the physiotherapists will come around on the first day after you operation and try to get you standing and taking steps with either crutches or more likely a zimmer frame. This improves recovery time and reduces the likelihood of complications such as a chest infection. They will also be very knee for you to start bending and straightening the joint so as to stop it stiffening up.
4. Discharge home is discussed: the physios and occupational therapists will come around and discuss with you what you need to do to get home. If you have stairs, then it is likely that before going home you will need to be able to go up and down a set of stairs.
5. Stairs: if you need to use stairs at home the physios will come around in the hospital and practice the stairs with you. Once you have successfully completed these and you are medically stable, the hospital staff will start preparing you for going home.
6. Home: all of your medicines should be packaged up and preparations are made for discharging you off the ward. This is usually done within 3 days after your knee surgery but sometimes can be quicker or take longer.

Recovering At Home

The next step of your recovery from your knee replacement is by far the longest and in many ways the most important. Once the doctors have determined that you are medically safe for discharge home after your knee replacement you will then be sent home. If you have someone who can pick you up then this is ideal otherwise it may be by ambulance or taxi. Once at home, resting and letting things settle down for at least a few days is the key. You need to do your exercises that you will have been given and you need to try and mobilise around your home a bit but you should not do too much and you need to accept you have just had a knee replacement which is major surgery! The key exercise to be doing at this point is to be bending the knee and straightening it. Getting a good range of motion established is key to a good result.

From this point timeframes of recovery and how well you progress after your knee replacement are very individual and hard to describe as it depends very much on your age and previous levels of fitness. In general, the younger and stronger you are the quicker and better you will recover from your knee replacement. However, it is important to realise that a knee replacement is very different from a hip replacement in terms of recovery and pain levels in the first 6 to 8 weeks. Many people will recover quickly from a hip replacement and never have really had large levels of pain but most people who have a knee replacement will find that the first month is dominated by pain and swelling of the knee.

So, now you are home and have had a few days rest what should you be expecting after your knee replacement? Well, as explained this very much depends upon your age and previous level of fitness. You should as described expect the initial period of a month to 2 months to be a period of trying to get the knee bending and straightening, pain and swelling. However after this period your knee should be improving and you should be having less pain and swelling. It may take quite a while to get off any walking aids such as a zimmer frame or crutches and you should certainly expect that it will take at least 12 months for your knee to have fully recovered.

Physiotherapy After A Knee Replacement

A key part of the recovery for anyone after a knee replacement will be physiotherapy. How much physiotherapy you need and how often after your knee replacement will depend upon a number of factors such as age, previous fitness levels and how easily you can do exercises yourself. In general though all patients will benefit from an early assessment by a physiotherapist with experience of helping patients with knee replacements. Having an assessment early on in the process will give you the information you need to make the best possible recovery after your knee replacement. Below is a general process covering physiotherapy after a knee replacement with a few scenarios and options:

The Initial Assessment:

Once home it is usually best to wait for about two weeks so that the stitches/clips can come out and the wound can fully heal before having an initial assessment with a physiotherapist. This initial assessment will involve taking a past medical history, discussing your current symptoms and understanding of the knee replacement. There will be a physical assessment that looks at how much you can do and how strong you are. After this the physiotherapist will give you an exercise program and discuss a management plan plus they should talk through time frames and key stages post knee replacement. This is probably the most important physiotherapy session post knee replacement for most patients as it gives them the information they need to manage their recovery themselves and maximise their chances of returning to previous levels of mobility.

Follow Up Physiotherapy Sessions:

How many sessions of physiotherapy you need and how often after your joint replacement very much depends upon how much you are able to do independently or with family help. If you are able to do all of your exercises yourself, are currently walking (with a couple of crutches) and are highly motivated then you will clearly need to only see a physio a few times. Possibly, you will see the physio once for the initial assessment, once a few weeks later and then a couple of times over the next few months until you feel happy to continue independently. However, if you have been discharged with a hoist for transferring then you will most likely be needing several sessions per week for at least a month or two in order to get off the hoist and begin attempting to mobilise with a frame.

How Can ThreeSpires Physiotherapy Help with My Knee Replacement?

Here at ThreeSpires Physiotherapy we help a large number of patients with their recovery after a knee replacement. Our physiotherapists are experienced in helping all categories of patients recover after a joint replacement. Our physiotherapists will visit you as soon as possible at your home after your operation and will help you on the road to recovery. Below I have tried to detail this process:

1. Assessment: this is a vital part of recovery after your replacement and the sooner you have an assessment with one of our physios the sooner you will know what you need to be doing to maximise your recovery.
2. Management Plan: once you have had an initial assessment our physiotherapist will discuss a clear and comprehensive plan to begin managing your recovery.
3. Exercises: your physiotherapist will be able to determine which are the most appropriate exercises for your knee replacement and will be able to prescribe the optimum number and frequency to promote recovery.

Okay, I hope that you have found this article about knee replacements helpful and it is part of a series of articles that we are completing about joint replacements. Should you or anyone you know need help with recovery after a joint replacement please get in touch and one of our physios would be happy to help. Just to remind you we are a home visit physiotherapy service and our physios are mobile and will come out to you at home.