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Knee Surgery

>   What are the common reasons people need treatment for knee problems?

The aim of most treatments for knee problems are to reduce pain, improve function and to return you to the activities that you want to do. This is important to remember as you may be told that you need treatment for a problem that has been picked up when you are not experiencing any pain or problems. It is often reassuring to know that this is very rarely the case, hence it is important to see someone who has a full and in depth understanding of the problems that can affect your knee and can accurately and reliably correlate your symptoms with any problems found. This means the best advice can be offered on what treatment you may need and when it would be best to perform this.

The most common reason that you may need to see a knee surgeon is due to pain. Certain patterns of pain suggest particular diagnoses. For example, knee arthritis typically leads to pain felt in over the inside or outside of the knee of just below the knee. The pain may radiate down the leg. Meniscal tears typically cause pain in these areas as well, but may only come on with the knee in certain positions or during particular activities. Meniscal tears are also more likely to cause other problems such as giving way or locking of the knee. Tendon or soft tissue problems around the knee may lead to sensations of instability or pain affecting particular points that you can locate yourself by prodding different areas around the knee.

>   Knee arthritis

Knee arthritis occurs when the cartilage and eventually the underlying bone wears away or degrades in the knee. The most common form is osteoarthritis. This is commonly referred to as “wear and tear” arthritis but this is not quite correct. Although it becomes more common as people get older or after they experience an accident where the knee is injured, if it was just wear and tear, most people would present with arthritis which was the same on both sides, which it rarely is. If you need a knee replacement, there is about a one in eleven chance that you would need to have the other side replaced in your lifetime. Osteoarthritis is a condition that affects the whole joint, not only the bearing surfaces that rub together. The lining of the joint, or synovium, is part of the process and the thick capsule that surrounds the joint becomes scarred and stiff as well. All of these factors can lead to symptoms that cause pain or otherwise affect you, such as with stiffness or reduced range of motion.


Knee arthritis: the effect of pain

Osteoarthritis of the knee most commonly causes pain. This pain means that you may tend to cut back on or stop doing activities that cause you pain which can be very frustrating and lead to other health problems. The scores that are used to assess how badly you are affected by your knee arthritis some questions about pain but most of the questions are about particular activities and how easy you find it to perform these activities. You may have been asked to fill in one of these scores by people that you have seen about your knee. The most common one in use in the UK is the Oxford Knee Score (OKS), which consists of 12 different questions. Although more questions are about activities than pain, the majority of the differences (around 80%) seen in different peoples’ scores or scores from the same person taken at different times, is actually due to pain. So, if we can reduce your pain, you will be able to do more of the activities you want to do. 


Knee arthritis: where is the pain felt?

The pain from osteoarthritis of the knee is typically felt over the part of the knee that is most severely affected. The knee is made up of three compartments, the medial (or inner) compartment, the lateral (or outer) compartment and the patellofemoral (or front) compartment. Osteoarthritis is most common in the medial compartment of the knee and pain is typically felt over the inner aspect of the knee and radiates down the inner border of the shin. If the rest of the knee is relatively spared, you may notice that you become progressively more bow legged. This happens due to the bones getting closer together on the worn inner part of the knee but the height being maintained in the outer part of the knee so the knee tips over. If it is predominantly the outer part of the knee that is affected, pain is felt over the outer part of the knee and you may notice that you become progressively more knock kneed. Around one in ten people are more affected in the outer than the inner part of the knee. If you feel that your worst pain is underneath the kneecap at the front of the knee, then you may have arthritis affecting the patellofemoral compartment of the knee. This is where the kneecap runs in a groove on the front of the femur, or thigh bone. In isolation, this is the rarest kind of arthritis in the knee, but it is common to see if multiple compartments of the knee are affected. Sometimes people will experience pain at the bottom of the thigh that they feel is coming from their knee, but we actually find out it is coming from the hip. This is called referred pain and happens due to the way that nerves supply different parts of the body. It is possible to have signs of arthritis on a x-ray that are not responsible for the pain that you are experiencing, hence it is really important to see someone with experience in the area that understands these issues to prevent treatments focusing on the wrong part of your body. If the pain goes below the ankle into the foot, it is very important that we rule out back problems that may be contributing to your pain as this may be due to problems such as a nerve being pressed on in the back. 


Knee arthritis: when do people feel pain?

The pain is typically associated with activity to start with. You may find that the knee gets painful after sports or walking distances that you used to find no problem. As the osteoarthritis gets worse, you may start to feel pain at rest, particularly sat in a chair in the evening. You may find that the knee feels like it seizes up if you have been in the same position for a while, such as sat in a chair or when you first get up in the morning. If you are beginning to get pain at rest or that you feel at night in bed, that is a strong indicator that your knee may benefit from treatment. National guidelines say that treatments of knee problems, such as knee replacement, should be considered before you need strong painkillers such as patches or opiates (morphine type painkillers)


Knee arthritis: stiffness

As the arthritis progresses, you may find your knee gets stiff. This can be due to the wear of the cartilage but is also due to spurs of bone forming around the knee and the scarring of the soft tissues that we mentioned earlier. It is rare for patients to experience stiffness with no pain but this can happen and if the stiffness becomes bad enough, this can be an indication that treatment is needed on its own. The first thing that people tend to notice is that the knee won’t come out fully straight anymore. If this progresses beyond a few degrees, you may find that your leg becomes tired much more easily. This is because the knee is not a simple hinge. As the knee comes out into full extension (when the knee is straight, such as when you are standing up), it also rotates and locks into place so that you can maintain this position even with the muscles in your thighs relaxed. If the knee will not come out fully straight, this rotation and locking can not happen so in order to stay standing up, the muscles in your thighs have to constantly work and hence get tired much more quickly. You may also notice that the knee won’t bend as far as it used to. People tend to first notice this when trying to get in and out of a car, which becomes more difficult as it is harder to manoeuvre through the car door. If the knee will not bend past right angles, it takes much more energy to get out of a chair and you will notice you have to use your arms more to help. 


Knee arthritis: giving way

True giving way of the knee, such that you fall to the floor, is relatively unusual with knee arthritis but is more common than with other joints such as the hip. Most of the time when it feels like the knee is giving way, it is due to episodes of pain that come on suddenly, catching you unawares and as your body tries to protect itself, the muscles spasm or you try to take weight off the knee. If there are true “mechanical” symptoms of the knee, where something locks in the joint or it truly gives way, this may be due to an unstable meniscal tear, loose bodies in the knee or part of the cartilage and/or bone coming away. When it does occur, this is most often part of severe arthritis but may be part of other problems such as avascular necrosis when the blood supply to the bone in the knee joint is damaged or stops working and the knee joint rapidly collapses. In the knee, the term “spontaneous osteonecrosis of the knee” is used to refer to this and it is usually seen in the condyles of the femur (the broad bits at the end of the thigh bone that make up the top part of the knee joint) In cases such as these, there tends to be severe pain which may require relatively urgent treatment or bracing to stop it progressing as rapidly as it otherwise would.


Knee arthritis: rheumatoid arthritis

The other main type of arthritis is rheumatoid arthritis. This is a very different kind of knee condition. Rheumatoid arthritis is a type of autoimmune condition where your body’s own immune system attacks the joints causing damage to the cartilage and erosion of bone and soft tissues around the joint. The chances of needing a joint replacement if you have rheumatoid arthritis have decreased a lot over the last few decades as the drug treatments for this condition have improved markedly. If your rheumatoid arthritis has severely affected your knee, or if you have had the condition for a long time, you may end up needing a knee replacement eventually. If you do, it is reassuring to know that despite this being a different condition, excellent results can still be achieved. We may need to alter or temporarily adjust the treatments you take for your rheumatoid arthritis around the time of your surgery. If we do need to alter your medication, we will discuss this with your rheumatologist if needed. Our aim will be to give you the lowest risk of complications such as infection or poor wound healing (which are more common for people with rheumatoid arthritis being treated with medications that affect their immune system) whilst trying to avoid a flare of your rheumatoid arthritis which can be painful and interfere with your rehabilitation. 

>   Knee cartilage or meniscal tears

There are two types of cartilage in the knee. The first is the articular cartilage, this is the smooth hard-wearing cartilage that is affected in knee osteoarthritis as we have talked about above. The second is meniscal cartilage. You have two meniscal cartilages, one in the medial (inner) compartment and one in the lateral (outer) compartment. This is a different type of cartilage, it is triangular in cross section and attaches to the capsule around the rim of the compartment and roots at the front and back attach more firmly to the bone and ligaments. These are commonly called shock absorbers, but they actually do very little shock absorbing. Due to their shape, they help spread load in the knee over a wider surface area. The curve of the bone at the end of the femur (thigh bone) and at the top of the tibia (shin bone) are not the same, hence if the menisci were not there, a lot of load would pass through a small area, leading to more rapid wear. The reason the shapes of the bones are different is to allow the gliding and rotating that happens in the knee as it bends and straightens as we discussed above. The cartilage of the menisci is more compliant, or flexible, than the articular cartilage on the ends of the bones, hence they can adapt to different shapes and loads. We know that if the menisci are totally removed (this used to be a common treatment for meniscal tears), arthritis develops much more quickly. If you imagine a person walking across a wooden floor in stilettos, they are more likely to leave marks in the wood than if the same person walks across the same floor in a pair of trainers. The amount of load is the same, but it is being applied through a smaller contact area (when there is no meniscus or the person is wearing stilettos), hence the wear (on the articular cartilage or wood of the floor) is greater. The menisci also joint lubrication, stability and proprioception (your ability to know where in space the joint or limb is without needing to look at it). 


The menisci are vulnerable to injury when there is load on the knee and a twisting motion is applied, hence they are common in people that participate in sports that involve these movements such as football players, rugby players, martial artists and skiers. As load is applied to the knee, the meniscus is held in a relatively more fixed position by this load and a sudden twist of the knee, such as when a football player gets their studs or blades stuck in the turf or when a rugby player suddenly changes direction to avoid a tackle, can lead to tearing or detachment of the meniscus. This may lead to pain and discomfort when the damaged bit of the meniscus has load put through it. Generally, the more flexed the knee, the further towards the back of the joint the load passes through the meniscus. In severe cases, there may be an unstable torn bit of meniscus which can make the joint feel unstable when weight is put through it of the knee is twisted. In the most severe cases, a large part of the meniscus can become torn but remain attached at the front and back, this can then flip over towards the middle of the joint, like a bucket handle flipping from one side of a bucket to the other. This can lead to the knee becoming locked which means it will have a suddenly reduced range of motion. The most common pattern we see is that the knee will no longer come out fully straight. This is very different to a knee that is painful and therefore is difficult to put through a full range of motion, which is much more common. In the case of a truly locked knee, relatively urgent treatment may be required to put the meniscus back in place and fix it before it becomes permanently deformed  and this can not be done anymore meaning we have to remove a relatively large part of the meniscus.


Although we can generally diagnose a meniscal tear from a history and examination, there are some other conditions in the knee that can closely mimic the symptoms and signs of a meniscal tear therefore in such cases, we usually will perform an MRI scan to determine the nature of the problem precisely. This will also help us to determine the best treatment for. You and to advise you before surgery of the likely time period for recovery and any restrictions we would need to place on you following your operation.


There are two main types of meniscal tear. The first is caused by an episode like those described above and is termed a “traumatic” meniscal tear. The implication of this is that it has happened due to trauma in an otherwise normal meniscus. In large tears, these may be amenable to repair or in smaller tears, you may need a relatively quick operation to remove the torn bit of the meniscus that is causing issues but would not benefit from repair. In the second type of meniscal tear, the meniscus is not normal and has become “degenerate”. This is unfortunately something that happens to us all as we get older; the meniscus becomes relatively more dehydrated and stiffer with age, meaning it is more prone to becoming torn. If your meniscal tear happened with a fairly innocuous injury or you do not know when it happened, you are more likely to have this kind of tear. This process is also something that happens in the early stages of osteoarthritis of the knee and it is common for us to see patients who have been referred for treatment of a “meniscal tear” when their pain is actually arising from osteoarthritis. This is an important distinction as the implications and treatment can be quite different. Degenerate meniscal tears are much less likely to be successfully treated with surgery due to the different pattern of tears that happen and the different healing potential. There is good evidence that the majority of patients with degenerate meniscal tears do no better with surgery than if no surgery is performed. We will therefore carefully explore the type of damage you have and the best treatment for you.

>   Knee ligament tears

There are four main ligaments in the knee, two cruciate ligaments and two collateral ligaments. If the kind of injury that you have is not one that I operate on myself and an operation is recommended, I will refer you on to one of my expert colleagues.


The cruciate ligaments are so called because they form a cross shape in the knee. They sit inside the knee joint itself. The anterior cruciate ligament comes from an area towards the back of the femur in the notch between the condyles and passes forward before attaching to the tibia. Its main function is to stop the tibia sliding forward underneath the femur when the knee is flexed. It can be injured by a direct blow but more typically is injured in twisting injuries on a knee that has weight on it, such as skiing, football, rugby, netball or basketball. We test this ligament by getting you to flex the knee then seeing if we can pull the tibia forward. The posterior cruciate ligament starts off further forward on the femur in the notch and passes backwards before attaching to the back of the tibia. Its main function is to stop the tibia sliding back underneath the femur when the knee is flexed. Although this ligament can be injured during sports, we most commonly see it when something has struck the front of the knee and pushed the tibia back, such as when someone has been involved in a car crash and the dashboard or shelf has hit the front of their knee. We test this ligament by getting you to flex the knee and looking from the side to see if the tibia is sagging back and not sitting as far forward as it should.


The collateral ligaments are outside the joint capsule. There is one on each side of the knee, the medial and lateral collateral ligaments. The medial collateral ligament is the most commonly injured and this usually happens during sports when another player strikes the outside of the knee causing the inside of the knee to open up and the ligament to pull off its attachment or tear. It can also happen in awkward falls that mimic this motion. We test this ligament by trying to mimic this motion with the knee partially flexed, seeing if the ligament is intact and hence resists this motion. The lateral collateral ligament is on the outside of the joint and resists the opposite motion. It is less commonly injured on its own but can be injured as part of complex injuries involving the posterolateral (rear outer) corner of the knee.


Knee ligament tears: anterior cruciate ligament

The anterior cruciate ligament is an important stabiliser of the knee and is the ligament that most commonly requires an operation. However, not all anterior cruciate ligament injuries require an operation and the symptoms it is causing and the success of other treatment strategies are all important parts of deciding if and when an operation is needed. In general, operating soon after an anterior cruciate ligament tear carries a higher risk of scarring in the knee (arthrofibrosis) and stiffness hence having a period of targeted physiotherapy or rehabilitation with or without bracing is a sensible first step. Some patients will go on to need an anterior cruciate ligament reconstruction due to frank instability of the knee, where the knee repeatedly gives way beneath them, but this is relatively unusual. One of the reasons for choosing to reconstruct an anterior cruciate ligament tear is to protect the knee from further damage in the future, the evidence for this is less clear and if this is something that is being considered, it will be carefully discussed with you. If an operation is required, this is usually a reconstruction rather than a repair. In a ligament or tendon repair, the torn structure is directly required by stitching it back together with or without augmentation or protection for the repair. This relies on the structure being repaired having the capacity to heal itself. Unfortunately, the anterior cruciate ligament has a very poor blood supply and hence potential to heal, hence the majority are reconstructed using graft material either taken from the hamstrings or from the tendon and bone around the kneecap.


Knee ligament tears: posterior cruciate ligament

Isolated posterior cruciate ligament injuries are relatively unusual. The vast majority of them are successfully treated with physiotherapy and bracing although recovery can take a long time, particularly if you place high demands on your knee. If there are persistent problems with the knee giving way, a delayed reconstruction may be necessary. Posterior cruciate ligament tears or injuries can be part of much bigger injuries that damage the stabilisers around the back and outside of the knee. Where there are multiple structures that are injured, it is more likely that an operation would be required but these may need to be done in sequence rather than all at the same time.


Knee ligament tears: medial collateral ligament

Medial collateral ligament injuries are common and quite often we see these in patients who have been told they have “sprained” the knee. There are different grades of injury that can occur to ligaments and tendons with the mildest leading to a ligament that may be painful when stressed but has no element of laxity, though to one that is completely torn. The description of a “sprain” may therefore be accurate, but it is important to know what has been sprained, so that it can be rehabilitated and/or protected effectively. The good news with medial collateral ligament injuries is that they rarely require anything other than a period of protection in a brace (to support the knee and prevent further injury) and self-guided exercises.


Knee ligament tears: medial collateral ligament

As described previously, isolated lateral collateral ligament injuries are one of the rarest ligament injuries around the knee. Similarly to medial collateral ligament injuries, there are different grades of injury but they rarely require treatment beyond physiotherapy and bracing. They can however be part of a more severe injury and we will check to make sure no other structures have been injured. If you get pins and needles down your leg or weakness in the foot, this suggests stretching of or injury to the nerve that travels around this side of the knee and is an indication that the damage may be more severe than first assumed.

>   Tendon injuries or pain

The most common site for tendon related pain around the knee is at the front. The extensor mechanism is what allows you to straighten out your knee from a flexed position and involves a number of structures including the quadriceps muscles in the front of the thigh, the patella (kneecap) and the patella tendon that runs from the bottom of the kneecap to the nobble of bone you can feel below your knee on the front of your tibia. A large amount of force passes through these structures so they are sensitive to problems that can cause pain. Tendons can develop areas of chronic damage (tendinosis) or inflammation (tendonitis) that are hard to properly rest or protect and hence hard to get to settle down. This can happen in either the patella or quadriceps tendons, the younger you are, the more likely you are to get pain further down the extensor mechanism so the patella tendon in younger patients and the quadriceps tendon, above the kneecap, in older patients. 


There are particular exercises which are very good for treating this kind of problem, called eccentric stretching exercises, where a tendon with load through it is slowly lengthened out and then shortened (or contracted). We can demonstrate these to you and there are videos available online but often physiotherapy is very useful whilst you learn these. 


These tendons can also be torn, this tends to happen in a fall when you try to stop yourself or when you putting more load through them than normal. Most people know about it straightaway when this happens although some present late when all they have noticed is some weakness. Big tears that happen suddenly tend to need repair but not all tears do so this will be carefully assessed to determine the best treatment for you.


Young patients (before their skeleton has matured) may get problems where tendons attach to bones due to repeated trauma or loads greater than the structures can cope with. The most common site for this is where the patella tendon attaches to the bottom of the kneecap and is called Osgood-Schlatter disease. The good news is that it tends to settle when the activity provoking it is avoided but it may also be helped by the stretches described above or other treatment such as pulsed ultrasound. Very rarely, an operation may be required to remove prominent lumps of bone that can form in the tendon, particularly if these cause big problems when kneeling although the scar that is left behind can also be tender.

>   Patellofemoral disorders

There are other conditions that affect the patellofemoral joint (the joint under the kneecap) that may cause problems. If the groove that the kneecap runs in is very shallow, or even domed shape, this can lead to problems with stability of the kneecap. In severe cases, the kneecap can dislocate repeatedly and is typically put back in place by straightening the knee. It is important in such cases to get the knee moving as soon as pain allows. If the knee is kept still in a cast or brace too long, the muscles in the thigh get weak and the problem gets worse. Strapping and physiotherapy can help in cases that do not need surgery or in patients that are getting ready for surgery. Although it is unusual to need surgery for this, if an operation is required for this kind of problem, I will refer you on to one of my expert colleagues in this area.


Pain at the front of the knee can be caused by softening of the cartilage under the kneecap. It is important in such cases to ensure that there are no underlying issues causing this. In those that there are no other problems, most can be successfully treated with targeted physiotherapy and injections. Pain can also be caused by tight bands of tissue in the knee although this a very rare cause of pain on its own and there are specific features that we look for in such cases as for the majority of patients with limiting knee pain, this will not be the case. As it is very unusual for this to cause pain on its own, we will use targeted injections to ensure that this really is the cause of your pain before suggesting treatment for this.

>   Non-surgical treatments

t is really important to know that not all knee problems will need an operation. If you are experiencing knee pain for the first time, although it is important we determine why the knee is painful, the chances are that once we know the cause, we can treat the knee in ways that do not involve an operation to improve things for you. If these do not work or your symptoms have been present for a while, we may need to consider surgery but part of my aim will be to explain all of the options to you so you can make an informed decision as to which kind of treatment is best for you.


Non-surgical treatments: doing nothing!

The most basic form of non-operative treatment is carrying on as you are! Much as this may sound a bit strange to start with, there are a variety of knee problems that are described as self-limiting. This means that they are problems that you might need to protect for a short while whilst a problem such as a muscle or ligament strain improves on its own.


Non-surgical treatments: pain relief medication

During a period of protecting the knee, after a knee injury or in the early phases when a knee begins to become affected by a condition such as arthritis, you may need to take pain relief. Pain relief comes in many forms. The most common type we think of is taking tablets such as paracetamol or anti-inflammatories. Caution should be taken with anti-inflammatories if you suffer from stomach irritation, have a history of bleeding from the stomach or the rest of the bowel, have asthma or problems with your kidneys. If these are not controlling your pain, then oral codeine can be added. If this is still not controlling your pain, it is important that other treatments are considered as national treatment guidelines recommend that we do not wait until strong morphine type pain relief is required before considering treatment such as knee replacement for arthritis.


Anti-inflammatories can also be applied topically, or rubbed into, the painful area. These have been shown to be just as effective as taking the tablet varieties but with a lower risk of side effects. This may be in part due to the benefit that comes from massaging the area.


Non-surgical treatments: TENS

Pain is transmitted from painful joints to the brain by nerves. The nerves that carry pain signals have a maximum frequency at which they can transmit signals to the brain. TENS (transcutaneous electrical nerve stimulation) works by applying continuous or pulsed stimulation to the nerves via the skin which reduces the number of pain signals that the nerves transmit. This can be an effective form of treatment and TENS devices are now small, battery powered and can be bought from most pharmacies. They are typically suitable to apply whilst you are at rest, but it is difficult to get them to stick or stay in place when you are moving.


Non-surgical treatments: hot and cold packs

You may already have tried applying hot or cold packs to the area and these can often provide some relief. Heat can be particularly effective for the stiffness that develops when the joint remains in the same place for a period of time or is aching. Just be careful to not apply packs or hot water bottles to the area directly to the skin if they are too hot and limit the time the packs are applied for to prevent skin damage. Cold or ice packs can be particularly effective if the joint feels inflamed or sore after activity, Again care should be taken not apply ice directly to the skin, you can wrap it in a towel or similar to prevent this and exposure should be limited to no more than 20 minutes at a time.


Non-surgical treatments: walking aids

You may find that you knee pain is helped by using a walking stick, crutch or other walking aid. If you do use one, then you need to use it in the opposite hand to the side you get pain on, the stick should be used so that it contacts the ground at the same time as the foot of your painful side and the weight shared between the stick and the leg. This leads to less force going through the knee and muscles around the knee, easing the pain experienced. It can also help prevent limping which leads to less load being put through other joints and may help symptoms there too. Even if you would prefer to avoid using a stick, it is worth doing so before going forward for surgery as you will need to use them in the early phases of your recovery so this will be easier if you are already used to them.


Non-surgical treatments: physiotherapy

Physiotherapy is an important part of the treatment of nearly all joint and musculoskeletal problems. The critical factor is the exercises and activity that you perform rather than who supervises the activity. It is perfectly reasonable to perform self-directed exercises in the first instance. Even if you are very active or even usually participate in sports to a high level, physiotherapy can still be of benefit as particular muscle groups may be weak, soft tissues overly tight or the joints themselves affected by contractures.


Physiotherapy can help by strengthening muscles that help support and offload joints. It can also help to improve the strength of muscles, such as the quadriceps and hamstrings that cross the knee, that help you walk normally and hence decrease the strain on other joints such as the back, hip and other knee. You may find as the muscle strength improves around the joint, that you experience less pain. Although some elements of the stiffness that you may experience can’t be improved with physiotherapy, such as that arising from the bone spurs that form when you have arthritis, tightness of the joint capsule and the muscles around the joint can be improved with exercises and therapy. 


Exercises should be commenced even if you think that you will definitely need surgery. The stronger we can make the muscles around the joint, the less likely it is you would need surgery but even if you do end up needing an operation such as knee replacement, it will make your recovery progress more smoothly and rapidly. If you do have an operation, physiotherapy exercises, either self-guided or under the supervision of a physiotherapist, will be a critical part of your treatment and recovery.


Non-surgical treatments: bracing and taping

Braces can form an important part of the management of knee injuries. If you have damaged a ligament, such as the medial collateral ligament, a hinged brace that allows your knee to bend but prevents side to side motion will compensate for the ligament and allow it to heal. It is of course important to wear the brace to achieve this and to provide pain relief. For injuries such as cruciate ligament injuries, there are particular types of brace available that compensate for the function of the injured ligament and stop the knee being unstable. These are also often used after treatment of such injuries to protect the reconstruction for a period of time until the knee is healed. 


If you develop arthritis either in the medial (inner) or lateral (outer) compartments of the knee, there are special braces, called offloader braces that can help your symptoms. These work by pushing on the leg above, at the level of and below the knee to direct the load passing through the knee to the healthy compartment. Hence, they offload the arthritic compartment and can decrease symptoms such as pain. Some patients find that such braces can completely control their symptoms although some do find them uncomfortable to wear.


For problems around the kneecap, taping may help by controlling the motion of the kneecap. This helps it run in the proper place as you bend and straighten your knee. The taping needs to be applied in a particular way and is normally applied by a physiotherapist. They can also show you how to apply the taping yourself if you find that this helps.


Non-surgical treatments: intra-articular injections

We will consider together whether it may be appropriate to consider injections into the affected knee. There are a few different situations where this may be appropriate. If you have problems arising from your back or hip and knee, they can be a useful way to separate out which is the main cause of your pain or how effective treatment such as joint replacement may be in improving your symptoms given your other problems. There are times when you may have pain due to arthritis in a joint, but it may not be the right time for you to consider an operation such as knee replacement to treat this. There may be other important things happening in your life at the same time so that you would prefer to delay definitive treatment or perhaps you are planning on retiring in the next few years and are looking for something to tide you over until you do given the recovery period following joint replacement. 


Sometimes you may suffer from marked pain, even if there is only early arthritis in the joint. This is because when cartilage breaks down, it causes irritation to the lining of the joint which then becomes inflamed and sore, producing more fluid and leading to a swollen joint. If the arthritis is quite early, it may not be appropriate to have a joint replacement as the symptoms may settle down or the benefits that surgery can offer may not be great enough to make the risks worthwhile. If this is the case for you, an injection can provide relief for a period of time, typically up to 3 months to see if your symptoms will settle. Lastly, you may decide that a knee replacement is too risky for you after we have discussed the benefits and risks of surgery. This may be due to other health problems that you have, making surgery more risky than it would normally be. In such cases, we may be able to improve your pain to a level where the symptoms are acceptable for you with one or more injections.


When injections into the knee are performed, we use local anaesthetic and steroid. This helps reduce the pain and inflammation in the joint. They are considered to be relatively low risk. One of the biggest risks is that they don’t lead to any benefit for you which is the case in about one in three patients. After the injection is performed, the knee may initially feel a bit more sore as additional fluid has been put into the joint and the steroid can be irritant to the joint before its anti-inflammatory effect kicks in. This is one of the reasons that we use local anaesthetic at the same time, to reduce this initial irritation. Any time a joint is penetrated, even when deliberately with an injection such as this, there is a risk of bacteria entering the joint and causing infection. For this reason, we take great care to ensure the injections are done under sterile conditions with the use of ultrasound or x-rays to guide us if needed. The risk of this is very rare and occurs less than one in five thousand cases. There is also a risk of bleeding, but we know where the major blood vessels are and avoid these. The risk of bleeding is increased if you take blood thinners and if this is the case, we may need to check your clotting levels before going ahead. If steroid from the injection escapes into the soft tissues just underneath the skin, it can cause a loss of pigment in the skin or dimpling due to atrophy of the fat cells. 


It is possible to inject other substances into the joint such as hyaluronic acid, platelet rich plasma or stem cells. All of these are expensive in comparison to local anaesthetic and steroid and have no good evidence of an increased benefit. Indeed, in the case of hyaluronic acid, the risk of adverse effects is higher meaning they should not be considered as a first line injection.

>   Knee arthroscopy

Knee arthroscopy is a form of minimally invasive surgery. Small incisions are made, typically at the front of the knee just under the kneecap, so that we can pass a camera and instruments into the knee joint. Using arthroscopy, we can perform close inspection of structures in the knee and remove loose bodies, torn bits of cartilage and carry out releases of tight bands or scarring that may cause problems. It is also possible to perform other operations such as cartilage surgery, ligament reconstruction and meniscal repair or replacement using arthroscopic surgery.


The advantages of arthroscopy include low risks of problems such as infection, due to its minimally invasive nature, short hospital stays (it is typically performed as day-case surgery) and quick recovery times. If your problem is suitable for treatment via arthroscopy, this option will be discussed with you.

>   Knee replacement

Total knee replacement

A knee replacement consists of removing the damaged joint and replacing it with a series of implants that replicate the function of the normal joint. The main aim of a knee replacement is to remove or reduce your pain and to improve your knee function, allowing you to return to the activities your knee has stopped you from carrying out.


In a total knee replacement, the knee is approached through an incision over the front of the knee, skirting around the edge of the kneecap for the deeper parts. the damaged and abnormal cartilage and bone from the end of the femur and the top of the tibia is then removed. Rods and guides are passed inside and fixed to the bones to ensure the implants are fixed in the correct places. A series of checks and trials are performed to ensure that the implants are the correct sizes and that the knee is balanced so that it moves smoothly. The undersurface of the kneecap, how the kneecap runs and the thickness of the kneecap are then checked. Overall, the chances of needing further surgery for your knee are reduced if the undersurface of the kneecap is also replaced therefore this will be done if it is safe to do so. Sometimes, it is not safe to do so, usually because the kneecap is too thin, in which case the kneecap will be left alone but we will ensure that it runs correctly if so.


Knee replacement implants can either be uncemented or fixed in place with cement. Which option is most suitable for you depends upon the quality of the bone in your knee, your age and the reasons you are undergoing the operation. We will select the best implants for you with the aim of achieving the most rapid and reliable recovery with the lowest risk of needing redo or revision surgery in the future. My aim is to give you one knee that will do everything you need and last you for as long as you need it to. By far the most common way to fix knee replacements in place is with cement due to the firm and long-lasting fixation this achieves. Certain parts of the knee, namely the liner that sits between the metal components fixed to the end of the femur and the top of the tibia, are modular, meaning they can changed relatively easily if they wear out or if there is an infection that affects the knee.


Unicompartmental knee replacement

Unicompartmental knee replacements may be an option for you if only one compartment of your knee is affected by symptomatic arthritis. It uses similar implants and strategies to total knee replacement, but the unaffected native compartments of the knee are left alone. There are certain requirements that must be met in order to perform a unicompartmental knee replacement, such as having functionally intact ligaments so that the knee is stable, and that the type of arthritis you have is suitable, it is very unusual to perform these in rheumatoid arthritis. There are advantages with unicompartmental knee replacements, the operation is quicker, the amount of soft tissue damage less, you will generally be in hospital for a shorter period and there are lower risks of problems such as blood clots forming and mortality. However, they will not address all of your pain if multiple compartments are affected and there is a higher risk of needing redo surgery in the future as arthritis can develop in other compartments of the knee. Although some surgeons perform multiple unicompartmental knee replacements at the same time in the same knee, the results of this strategy are not yet clear and it should be considered an experimental method at this time. If you are a candidate for unicompartmental or total knee replacement, I will carefully discuss the options with you. If you do prefer to consider a unicompartmental knee replacement, I will refer you on to one of my expert colleagues as I do not perform this kind of operation. The results of unicompartmental knee replacement appear to be much better when performed by surgeons that perform high numbers, hence it is important that the right surgeon performs this operation for you.

>   Redo or revision knee replacement

Knee replacements can unfortunately fail. This can lead to pain and other problems with the knee that mean further surgery may be needed. It is very important that we understand the reasons why the knee replacement has failed so that we can plan operations to address these reasons and ensure the best results. Revision knee replacements are usually bigger procedures than first time knee replacement and there will be more scarring after they are performed. This can mean that recovery will take longer than it did after your first knee replacement. I do not perform revision knee replacements so if you do require this operation, I will refer you on to an expert colleague for this.

What are the benefits and risks or knee replacement?
>   Knee replacement - risks/benefits

As described on the knee conditions and knee treatment pages, the intended benefits of surgery and to safely and effectively treat your pain and to restore you back to your normal level of function. 


Modern knee implants are made of robust and hard-wearing materials. This means that will serve you well even under demanding loading conditions such as cycling, running and skiing. It is advised that caution is taken with activities that lead to repetitive forceful unloading (taking the weight off the foot and leg) and loading (putting the body weight forcefully down on the foot) of the knee as these may accelerate the wear of the knee bearing surface. If your preferred activities and sports involved long distance endurance running on hard surfaces (such as tarmac) or competitive mogul skiing, then we can discuss this and select the best option for you.


There are a number of things that will or can happen after your knee replacement that you need to know about before deciding whether surgery is the right thing for you. We will discuss these together when you are deciding whether to have a knee replacement and we will both sign a consent form to say that we have discussed these and that you have had the chance to ask any questions you may have. If we complete the consent form in clinic, we will confirm on the day of surgery that you are happy to proceed and have no further questions.




  • Scar: you will have a scar over the front of your knee. The length of the scar will depend upon the thickness of the soft tissues and the complexity of your knee replacement. We will use an incision that is long enough to safely perform your operation bit not one that is longer than necessary. The scar may remain tender until the wound and soft tissues are fully healed. Although it is safe to kneel on a knee replacement after the wounds are all healed, not all patients like the sensation of doing so. If there are any problems with the wound healing (such as fluid discharge from the wound or redness around the wound), it is important that you contact my secretary, or if you are unable to speak to them, the hospital where you had your operation performed so we can review the wound and make sure everything is satisfactory or start any needed treatment.


  • Bleeding: The risk of injury to a major blood vessel requiring repair during a knee replacement is very small. Most of the bleeding that occurs is from smaller blood vessels and this will be stopped at the time that it occurs during an operation. It is unusual now to need a blood transfusion after a first-time total knee replacement, but your blood levels and symptoms will be checked before your operation and monitored afterwards. If your levels are low before your operation, we may recommend that you have iron supplements or come into hospital to receive an iron transfusion (iron given via a drip) to improve these. You may also need investigations performed to establish why they are low so that this can be treated. We will ensure such factors are optimised before surgery to reduce the risks for you. If the blood levels are a little low after the operation, you may need iron supplements. If they fall further or you develop symptoms related to low blood levels, you may need a blood transfusion. Very rarely, you may need a blood transfusion during your operation, this is more common in revision surgery but still rare. We would only do this if absolutely required. You may develop a haematoma (collection of blood) around the knee or under the skin. If this is large, it may require evacuation although this is rare.


  • Blood clot formation in the veins or lungs: Blood clots may form in the deep veins at any time but the risk of this happening increase with periods of immobility and when undergoing operations. Your risk will therefore be increased by undergoing knee replacement surgery. We will take steps to reduce the risk of this such as using pumps on your feet and calves during the operation and until you are mobilising, mobilising you as soon as is safe to do so after the operation, by using compression stockings in hospital if these are safe for you (the current national guidance is that these do not need to be continued after you go home), keeping you well hydrated and giving you medication to make blood clots less likely. Medication options include injections of heparin in hospital followed by aspiring after this, tablets such as rivaroxaban or continuing your own medication if you are already on a drug to reduce the risk of clot formation. If a clot does form in the deep veins of the leg, it may go to the lungs and be a serious threat to your health.


  • Infection: Infection can be a serious complication after joint replacement. Sometimes an infection may only be superficial and relatively simple to treat, requiring antibiotics alone. If the infection is deep and affects the tissues around the joint replacement itself, attempts to treat and cure the infection will involve further surgery. If we catch the infection early, we may be able to treat the infection by removing the infected tissue and replacing the exchangeable parts (such as the tibial liner/insert). If the infection is established or has been partially treated for a period of time, surgery usually involves the removal and replacement of all of the implants, a much bigger operation that may need to be done in multiple stages. This is why it is important that you let us know if you have problems with the wound or anyone suggests prescribing antibiotics for infection around the knee. The risk of undergoing revision for deep infection after first time surgery is between 0.3 and 0.6%. It can be higher if you are diabetic, have a high body mass index or other risk factors we will discuss. Following revision surgery, the risk of infection is higher at around 1.4% overall.


  • Pain: You will have some pain after the operation. Our aim is to keep this to a minimum and certainly to keep it under enough control so that you can mobilise and perform your exercises. It is generally easier to take regular pain relief to try to keep out of pain than it is to get you out of pain so I do recommend taking regular basic pain relief (such as paracetamol, anti-inflammatories and/or codeine) for at least the first couple of weeks after the operation. When you first wake up from the operation, the knee will usually be comfortable as the anaesthetic and local anaesthetic we inject into the wound are still working. If you begin to feel pain and this is increasing, please let the nursing staff know so that your pain relief can be reviewed.


  • Long-term pain: Between one in five and one in ten patients report that they get persistent pain in the longer term after knee replacement. Some of these patients still feel that it was worth having the operation done as the pain is better than it was or because their symptoms have improved in other ways however this is not always the case. Some patients do tell us that they would not have had the operation done if they had known what the result was going to be like. This is why it is critical that we fully explore the nature of your pain and why you are getting it, as well as other potential sources and how much they are contributing to make the risk of this as low as we can.


  • Stiffness: Your knee may become stiff after a knee replacement. Generally, those at greatest risk are those with a very stiff knee prior to the operation. Knee replacement generally improves range of motion, but this is not guaranteed. Very rarely, patients form bone in the soft tissues and muscles (heterotopic ossification) after surgery or injury and this can occur after knee replacement. If this has happened to you before, there may be steps we need to undertake to reduce the risk. If it does happen to you and it makes the knee very stiff, an operation to excise the bone may be required. If the knee is stiff but this has not happened, we may need to take you back to the operating theatre to perform a manipulation under anaesthetic in order to break down scar tissue and get the knee moving. If you do need this, I recommend a short stay in hospital to have intensive physiotherapy and use a machine that will keep the knee moving through a good range of motion to prevent recurrence. Rarely, operations such as arthroscopy or revision can be required to treat stiffness.


  • Numbness: Nearly all patients will experience some numbness after a total knee replacement. This will be felt along the scar itself. Initially there may be a fairly large patch of numbness to the outside of the scar, but this improves over the first few months after the operation and generally resolves leaving a narrow strip of numbness along and to the outside of the scar. There can be numbness caused by bruising to, swelling around, or damage to one of the large nerves that travels past the knee as described below although this is unusual unless there is a large deformity of the knee before the operation.


  • Nerve injury: There are large nerves that travel past the knee that are close to where the operation takes place. If there is an injury to a major nerve, it can cause numbness further down the leg or weakness of muscles. If there is bruising or swelling, this normally resolves within a few months of surgery, but you may need to wear a splint or carry on using crutches to stop you tripping. The chances of nerve injury are less than 1% but are increased by factors such as having had previous knee surgery, scarring and severe deformity. Direct injury to the nerve is very rare, if this does occur, surgical exploration or operations to repair the nerve or transplant tendons may be required. 


  • Fracture: When your bones are being prepared during the operation or implants inserted, there is a risk of fracture of the bones. The type of operation that is performed for you will take account of these risks and implants that minimise this risk for you will be selected. If a fracture like this does occur during your operation, it will either be fixed, or we will switch to other implants to bypass the fracture. The aim will be to perform an operation that allows you to fully weightbear straight away. Fractures around knee replacements can also occur in the years after surgery, typically if you have a fall or other form of trauma. If this does occur, revision surgery may be required to address this. The risk of a fracture occurring is less than 1%.


  • Adverse reaction to debris: All types of joint replacements will produce debris of one kind or another. This can either due to wear of the bearing surfaces themselves or due to corrosion or wear from modular junctions where implants are fixed together. Some of the materials released can cause problems such as soft tissue destruction and may have effects on remote organs although this is much rarer in knee rather than it was with certain kinds of hip replacement. Reaction to debris can also need to the lead for revision. With the kind of implants that I use, the risks of this are very low.


  • Wear and loosening: As time goes on, bearing materials will wear and implants that are fixed to bone may become loose. These are the most common reasons for revision of knee replacements in the long term. Over 95% of total knee replacements will last for 10 years or more and over 80% will last for 25 years or more.

What will undergoing total knee replacement involve?
>   The process
Benefits and Risks

Prior to surgery

We will discuss all aspects of your operation in clinic prior to you deciding whether you want to go ahead with surgery. If any further questions come up, you will be able to contact me via my secretary so these can be addressed and we can always change the treatment plan if you have any doubts.


You will be seen in the preoperative assessment clinic where our nursing staff will carry out a detailed assessment. Any necessary investigations that you need prior to surgery such as blood tests, heart traces and x-rays will be performed. You will be advised which of your medications to take up until the day of surgery, any you need to stop in advance (such as HRT and blood thinners) and which ones if any you should take on the day of surgery. If necessary, you will also see an anaesthetist if there are any elements of your medical history that put you an increased risk of problems at the time of or after surgery.


You will also be assessed by occupational and physiotherapy to commence preparation for your postoperative period and rehabilitation. You may be asked to fill in some forms to aid this process and you may need to take some measurements of furniture in your home to complete these.



My secretary will be in touch to provide you with the details you need to know for admission. You will be told where to report to and what time to be here. On the day of your knee replacement, you will be asked to not eat food or drink anything other than clear fluids for at least 6 hours before your operation. You may carry on drinking clear fluids up until 2 hours before the operation. Avoid using chewing gum for 6 hours before the operation.


From reception, you will be shown up to the ward, admitted to your room and you will meet the nursing staff and physiotherapist who will be caring for you. You will also see both myself and my anaesthetist on the ward. I will confirm your consent with you and answer any further questions you may have. My anaesthetist will describe the anaesthetic options to you and discuss with you which would be the best option for you. Any additional interventions that may be needed, such as a catheter, will also be discussed.



After all of the above has occurred and paperwork been completed, you will be taken down to the anaesthetic room adjacent to the operating theatre. Here you will be met by the anaesthetic team and your anaesthetic performed.


Following your anaesthetic, you will be transferred to the operating theatre. We will then move you across to the operating table. You will lie on your back with props to the side of your leg and under your foot to support your leg during the operation. We will then prepare you for surgery and perform the operation.


Once the operation has been performed and the wound closed, you will be transferred across to your bed and taken round to the recovery area where you will be monitored one to one by a member of the nursing staff until you are recovered from surgery and safe to return to the ward.


Ward stay

Once back on the ward, your pain and recovery will be closely monitored by the nursing staff. Please let them know if you feel you are in pain and they will review your pain relief. Once you have recovered from the after-effects of the anaesthetic, you will be mobilised by the ward staff. You can begin performing exercises in bed before you first get up. You can exercise your ankle, knee and hip. You will initially learn to transfer to the chair and you will practice walking with a zimmer frame before progressing to walking sticks or crutches. Once you have mastered these, the physiotherapists will teach you how to safely climb and descend stairs.


When you have achieved your rehabilitation targets and medically you are stable with your pain under control, you will be safe to be discharged home or to where you have arranged to go for the postoperative period. You can stop using the compression stockings at this point, unless specifically advised otherwise by myself. 


Fit note for work

If you do require a note for your employer, please let us know whilst on the ward prior to discharge so this can be completed for you. If you subsequently find that you need one after discharge, please contact my secretary and one can be completed and posted to you or given to you at your next clinic appointment.


If you have a fit note for work, you do not need to be signed “back on to work” at the end of this. If your employer requests this, please direct them to the advice available from the DWP here:


Follow up

Before leaving the ward you will be given a follow up appointment in the outpatient department at 2 week for a wound check by the nursing staff or advised to contact your practice to arrange a wound review with the practice nurse.


There are no sutures or clips to be removed so at the wound check, the dressing will be removed along with some small steri-strips that will be under the dressing. It is usual to then give you a further temporary dressing for the wound that can stay in place for a couple of days before being removed.


Your first outpatient appointment with me will be at either 6 weeks or 3 months. You will have an x-ray performed and we will check on the progress of your knee.


You will be followed up until at least a year after the operation is done, in accordance with the guidance issued by the national specialist societies.


Return to driving

The DVLA advise that in order to return to driving, you must be confident that you are able to fully control the vehicle.

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