Part of Total knee replacement rehab
Things to avoid after a knee replacement: what ends when, and what stays
Warning signs, and when to get help
What should you avoid after a knee replacement?
Three groups of things, and they run on three different clocks. The first protects the wound and the skin while they close. The second protects a knee that is still swollen and still winning its movement back, and that group is the NHS early precautions. Last comes the long-term position on impact, which has no end date and belongs to your surgeon.
Almost every list of things to avoid after a knee replacement folds those three together into five or seven numbered items. That is how two lists end up contradicting each other, and why neither one tells you when anything stops applying. Sort your own question into a group first and the answer usually follows.
Before any of that, one instruction outranks the page. Your surgical team's plan comes first, and if they told you something that differs from anything here, do what they said. They know which operation you had, what they found while they were doing it, and what else is going on with you. If they also gave you a limit on how much weight goes through the leg, that limit governs everything below it, and you ask them when it lifts rather than working it out from a website.
A knee replacement does not come home with a list of positions you are banned from. There is no angle you have to keep out of. If anything the pressure runs the other way, because getting the knee to bend and to straighten fully is the main job of the first months, and the person who decides to protect an expensive operation by bending it as little as possible is the person who loses movement that is genuinely hard to get back. A section near the end is about that, and for a lot of readers it is the only section that will change anything.
One quick note on scope. This page is about movement and activity. Plenty of people searching this phrase are asking about food, and there is nothing here on that, because it is not a physiotherapy question and we have no sourced answer to give.
To place any item you are unsure about, ask what it is protecting. The skin and the wound heal on their own schedule. The swelling and the stiffness are what the NHS list is aimed at. The implant has to last years, and that is where the impact advice sits. The detail of your own program, with the exercises and the doses in each stage, is on total knee replacement rehab.
While the wound and the skin are healing
This group is short, and all of it is about a surface, not a joint.
Kneeling is the item everybody asks about. The NHS instruction is not to kneel on the new knee until your doctor says you can, and it puts no date on it, so the timing is a conversation and not a calendar entry. The concern is the skin and not the joint underneath it: a review of kneeling after knee replacement advises against kneeling on a rough or uneven surface because of what that can do to the skin over the top, which can let bacteria in (Wylde and colleagues, 2019). An infection reaching a new joint is a serious problem, and that is the risk being managed, not the implant giving way under your weight. The rest of the kneeling answer, including what to kneel on and what the research found about who manages it, is on kneeling after a knee replacement.
The wound sets the timing for water as well as for pressure. OrthoInfo asks you to follow your doctor's instructions on bathing and showering, and says swimming can start as soon as the wound is sufficiently healed. That is the pattern across this whole group: the activity is not the problem, the open skin is, so the date comes from whoever is looking at your wound.
Two things here are not precautions at all, and they get missed because they look like them. Numbness in the skin around the scar is common after this operation, and it matters for one practical reason, which is that numb skin cannot tell you an ice pack has been on too long. The ice method and the skin check are on total knee replacement rehab. And a wound that is getting redder, hotter or more painful, or that is still leaking in the second week, is not something to be careful around. It is a same-day phone call, and the wording is in the warning signs below.
While the knee is recovering: the NHS list and what each item is for
The NHS early precautions run alongside the exercises rather than apart from them: do not kneel on the new knee until your doctor says you can, do not sit with your legs crossed for the first 6 weeks, avoid twisting your knee, bending down or reaching up as much as possible, and leave household tasks that involve lifting or moving anything heavy for the first 3 months.
The same page adds two more that belong in this group. Do not stand for long periods, and the reason the NHS gives is swelling in your ankles. And do not sleep with a pillow under your knee, which is about the knee stiffening in a bent position overnight. The night side of that is on how to sleep after a knee replacement, and what to do with the leg during the day is on total knee replacement rehab.
Now take the items one at a time, because they are not all the same kind of thing.
Sitting with your legs crossed carries the only firm date in the list, 6 weeks. The NHS does not say why, and this page is not going to supply a reason it does not have. What it is clearly not is a rule about a joint coming apart, so if you have read that explanation somewhere it was written about a different operation. Treat it as what it is: a restriction with a date and a source, which ends.
Twisting, bending down and reaching up is the odd one, and the odd part is the wording, because the NHS asks you to avoid it as much as possible rather than to avoid it. It also sits strangely next to a rehabilitation program that spends its first weeks deliberately bending the knee. The reading that makes practical sense of it, and this is clinic experience rather than a published rule, is that it is about the awkward loaded movements of a normal day: turning your whole body while the foot stays planted, dropping down to a low cupboard, stretching up on tiptoe for a high shelf. Stepping your feet round instead of pivoting on them is free, and it becomes a habit within a week. What the instruction is not is a reason to skip the bending exercises you were given, and if yours reads that way to you, ask your team to tell you which is which.
Heavy household tasks carry 3 months, and the NHS gives vacuuming and carrying shopping as its examples. It does not attach a weight to the word heavy, so neither does this page. The practical version is that while one hand is on a crutch or a stick, anything you carry has to sit in the other hand without making you lean, snatch or hurry the last step, and a trolley, a rucksack, a delivery or simply sliding things along the counter beats carrying them. If you live alone, arrange this before you come home. It is a poor thing to be solving on the day.
Standing for long periods has no date on it, which is the NHS leaving it to your swelling. Watch the swelling, not the clock, and break up the long stretches instead of trying to earn them.
What the program in those weeks actually asks of you is set out on the exercises for weeks 0 to 2 and the exercises for weeks 2 to 6. The aid is its own question, and dropping it early is one of the commoner ways people hurt a new knee, which is why how long you use a walker exists. Stairs are the item people expect to find on an avoid list and do not: they are a method rather than a hazard, and stairs after a knee replacement sets out the rail, the one step at a time pattern and which leg leads each way.
Driving is the one item from this period that a leaflet never explains properly. The NHS asks you to wait at least 6 weeks after a total knee replacement, or 3 weeks after a partial one, and to check with your doctor that you are fit to drive. OrthoInfo adds the condition that catches people out, which is that it is usually safe to drive again once you are no longer taking opioid pain medicine and your strength and reflexes are closer to normal. Never stop or change a prescribed medicine on your own, and if your pain relief is the thing standing between you and the car, that is a conversation with your prescriber, not a decision to make quietly. Driving after a knee replacement takes both those tests further, along with the insurance question.
Flying is an ask rather than an avoid, and it is the one item in this group that people book before they think of it. OrthoInfo wants your doctor's view before you fly, since cabin pressure changes and a long spell sitting still can both swell an operated leg that is still healing, and the clot warning lines at the end of this page are the reason the question is worth putting. The exercises for weeks 6 to 12 carries that one in full.
Exercises to avoid after a knee replacement
The honest answer is that the exercises to avoid after a knee replacement are mostly the ones that are not in your program. So start from the program. It is more use than any avoid list.
Everything in the staged program was chosen for this operation, in an order, with doses attached. If an exercise is not in it, the question is not whether it is banned but what it asks of the knee, and who decided you were ready for it.
Jumping has a clear answer. If you have had a hip or knee replacement, get the go-ahead from your surgeon before you try jumping or hopping. Many surgeons advise against jumping and hopping after a joint replacement for good, not just for the first months, because each landing sends high impact through the new joint.
Running is the same question with the same source behind it. If you have had a hip or knee replacement, get the go-ahead from your surgeon before you try running or jogging. Many surgeons advise against running and jogging after a joint replacement for good, not just for the first months, because each step sends impact through the new joint. Running has more on that decision.
Depth is the variable to watch in anything squat-shaped, and your team sets it, not your own sense of what felt all right on the day. The mini squat and the slow-lowering eccentric squat are both in the program with a ceiling on how deep to go until your surgeon or physio sets one for you. Those ceilings are written out in stage 3 on total knee replacement rehab, and a limit is worth carrying on a page about what to avoid, so here they are: until your team gives you a depth, keep the slow-lowering squat inside a right angle at the knee, with your hips staying above your knees, and keep the supported single leg squat to about a quarter of the way down, with the thigh of the standing leg well above level. The load through your kneecap and the tendons at the front of the knee climbs as the knee bends further and is at its highest around a right angle, which is why a shallower bend is never the risky choice here (Wallace and colleagues, 2002). Ask about depth before you add any loaded squatting, and take the gym and lifting with you when you ask.
Classes are harder than individual exercises because a timetable tells you nothing. The thing to take to your physio is not the name of the class but the movements in it, particularly anything that puts you on the floor and asks you to get back up, anything that turns your body over a planted foot, and anything that lands. Ask what to skip and what to swap. That is a two-minute conversation, and it saves a bad week.
Two exercises worth naming on the other side, because people stop doing them out of caution. Heel slides are the bend, and the bend is the thing you cannot buy back later. Sit to stand is the strength you need for every chair, every toilet and every car for the rest of your life. OrthoInfo asks people to keep going with the exercises their physical therapist or physio gave them for at least 2 months after the operation, and the later work is on the exercises for weeks 6 to 12.
One page on this site looks as if it answers this question and does not. Exercises to avoid with knee arthritis is written for a knee that has not been operated on, where the joint surface is the problem and the advice follows from that. A replaced knee is a different mechanical situation and a different set of rules, so do not read one as the other.
What most surgeons advise against for the long term
Impact, and the reason given is wear.
OrthoInfo says most surgeons advise against high-impact activities such as running, jogging, jumping and other high-impact sports, and it frames that as advice for the rest of your life after surgery rather than for a healing period. It explains the thinking in the same place: every total knee replacement implant begins to wear in its plastic spacer, too much activity or too much weight may speed up that normal wear, and that wear may in turn cause the knee replacement to loosen and become painful.
That last clause is the whole point of this tier, and it is the part the short lists leave off. The worry is not that one hard landing snaps something on the day. It is that wear in the plastic is the route by which a knee that was solid becomes loose and sore years later, and the same source lists components loosening and implant surfaces wearing down among the things that can go wrong with a knee replacement over time. So this tier is not about an accident waiting to happen in the first months. It is about years of load on a bearing surface, and the routine warning line at the end of this page, about pain that had settled and comes back or builds month by month, is what it looks like when it does happen.
One qualification on where that advice comes from. OrthoInfo is describing a total knee replacement. A partial, or unicompartmental, replacement is a smaller implant in one half of the joint, and the long-term activity advice after one is not automatically the same, in either direction. If that is the operation you had, the limits come from the surgeon who fitted it, and partial against total knee replacement sets out what else differs.
High impact is not another word for active, and the same source is explicit about what it does recommend. Walk as much as you would like. Swimming is called an excellent low-impact activity after a total knee replacement, once the wound is healed enough. Golf, bicycling and pickleball are named as lower impact activities that will help increase the longevity of your knee and are preferable to high-impact activities such as jumping, jogging and skiing. OrthoInfo also asks you to keep watching your weight, to avoid putting more stress on the joint, and it is weight alongside activity that it names as able to speed up that normal wear.
Two qualifications go with that, and both matter. Most surgeons hold this advice, and it is not a universal rule. Your surgeon is the one who knows your implant, your bone and how the knee went in, so a review appointment settles it and a web page does not. The second is that a single afternoon is not what the long-term advice is about. It is a statement about accumulated load, not about one game.
Which sports that leaves you is not this page's question, and it has a page of its own. Sports after a knee replacement sets out what golf, cycling and tennis each ask of a new knee, what the research does and does not show, and how readiness is judged.
Three items on this tier are not about activity at all, and they catch people years later. The first is dental. OrthoInfo asks you to let your dentist know that you have a total knee replacement, and to talk to your orthopedic surgeon about whether you need antibiotics before dental procedures. The instinct to avoid the dentist is the wrong one here. Avoiding the appointment is not the protective move; telling them about the joint is.
The second is any other infection, because the joint can be reached through the bloodstream rather than through the knee. OrthoInfo names dental procedures, urinary infections and skin infections as the common ways bacteria get into the blood and lodge around a knee replacement. So an infection somewhere else in your body is not one to sit out once you have a new joint: get it treated, and say that you have a knee replacement when you do. The warning line at the end of this page about new knee pain with a temperature, at any point in the years ahead, is the other half of the same subject.
The third is the appointment itself. OrthoInfo asks you to see your orthopedic surgeon periodically for routine follow-up examinations and X-rays, and says your surgeon will tell you how often and when. Those visits are how wear and early loosening are found on a film while the knee still feels more or less fine, which is a good deal earlier than symptoms arrive. A review skipped because nothing hurts is the one worth keeping.
How long does each kind last?
They run on different clocks, which is why no single number answers this question.
The wound and skin group ends when the wound has healed, and the person who decides that is the one looking at it. Kneeling has no published date from the NHS at all, which is deliberate: it hands the timing to your doctor.
The NHS early list has exactly two dates in it. Sitting with your legs crossed for the first 6 weeks. Heavy household tasks for the first 3 months. Everything else in it is left open, and open is not an oversight. Standing and twisting end when your knee stops reacting to them, which is a condition and not a date.
The long-term group has no end date, because it is not a healing restriction waiting to expire.
Then there is the part no page can date for you, which is anything your own team added. Those instructions were written for your operation, and they override the general list in both directions, so a date from here is never a release from theirs. The NHS says you will have a follow-up appointment about 6 weeks after the operation to check you are recovering well, and that is the natural place to go through your own list item by item and ask which ones are finished. Write them down before you go. The whole arc of the recovery, with each figure attributed to its source, is on the recovery timeline week by week.
What if you have already knelt, twisted or crossed your legs?
Start with the symptoms, not with the movement. The symptoms are the part that changes anything.
Three of the warning lines below belong to this question, and they come first for a reason. A fall or a knock, including a small one, that leaves the knee newly painful, swollen or bruised needs your surgical team the same day, with the exercises stopped, your crutches or sticks back in your hands and your full weight off that leg while you wait, even if you can still walk and the leg looks normal. A sudden inability to straighten the knee or to lift the leg straight when you could before, often after a pop, a tearing feeling or a stumble, is a same-day call too. And if you broke the skin, the wound lines apply, with everything they say about redness, leaking and a temperature.
If none of those is happening, then here is the straight answer. One crossed leg, one kneel or one awkward twist is not how a well-fixed knee replacement comes to grief. The knee is expected to be used from the start, not protected from use: NICE asks for rehabilitation to begin on the day of surgery where possible and within 24 hours otherwise, and the NHS says nurses and physiotherapists will help you start walking soon after the operation. That is not permission to treat the list as optional, and it is not a promise about your knee, which this page has never seen. How secure your own implant is early on, and what it can take, is a question for the surgeon who put it in, because it depends on how it was fixed and on what they found in your knee. How it was fixed is a genuine difference and not a technicality: a cemented implant is held by cement that has set hard before you leave the operating room, while a cementless one depends on your own bone growing into the surface of the implant, and that is a process over the early months rather than something finished on the day (Polizzotti and colleagues, 2023). Most people are never told which they had. It is a fair thing to ask at the follow-up appointment, and it is the kind of question that makes a general list more useful to you. It is a reason to stop lying awake auditing a single moment, and to raise it at your next appointment instead.
What deserves attention is a pattern, not an incident. A knee that is more swollen every evening, a knee that has stopped gaining movement week to week, or pain that is building rather than settling is worth raising whatever you did or did not do. Two of those are not the same speed, so do not treat them as one. Pain that keeps building while you are resting and not only while you move, a knee that is hot or red, or a temperature, goes to your surgical team the same day, because an overdone week and an infection around the new joint both show up as a knee that is more swollen and more painful and you cannot tell them apart from the inside. A normal temperature is not an all clear either: OrthoInfo's page on infection after a joint replacement says fever is no longer considered a sign of an infection after a joint replacement, and that the signs can be as little as mild redness and swelling. A knee that has stopped gaining movement goes to your physio or surgical team within a few days rather than at your next routine appointment, and it is time-sensitive in a way most readers do not expect. Both are in the warning signs below with the urgency each one needs.
The avoiding that costs more than it saves
Every list of this kind we have read leaves this section out, and it is where the real harm sits.
The commonest mistake after a knee replacement is not kneeling too early. It is doing too little, too carefully, for too long. A knee held quietly straight because bending it feels wrong gets stiff, and stiffness after this operation is far harder to undo than it was to prevent. The warning line below about a knee that has stopped bending or straightening from week to week carries the reason it is urgent: where a stiff knee has to be freed up under anesthetic, doing that earlier is associated with regaining more movement than doing it later, so the date you raise it genuinely matters.
Notice how early the official thinking starts. NICE, in its guideline on hip, knee and shoulder replacement, asks services to begin rehabilitation on the day of the operation where that can be done, and within 24 hours of it otherwise. Nobody writing that expects a period of protective rest. The same guideline asks that anyone carrying on alone at home is given clear goals and someone to contact for advice, and that supervised outpatient rehabilitation is offered to people who are finding daily activities difficult, who have ongoing problems with function and particular needs, or who are not meeting their goals on their own. If that last description fits you, the answer is more help, not more caution.
Then the things people quietly stop doing and never ask about.
Walking. OrthoInfo's position is that you can walk as much as you would like. Your distance and your aid still come from your physio, but the instinct to ration walking is not supported by anything.
Bending the knee. It is the work. Every program on this site puts it first for the first fortnight, and the whole reason the early weeks are busy is that movement regained early is movement you keep.
The compression stockings. They are hot, they are awkward to get on, and they are the one item on the early list that is there for your blood rather than for your knee. The NHS asks for compression stockings to be worn at all times, taken off only for washing, and says most people need them for at least 6 weeks. Quietly giving up on them early is an avoiding that costs something, and the clot lines at the end of this page are the reason it is worth the nuisance. If the problem is that you cannot get them on alone, that is a question for your team rather than grounds to stop.
Kneeling, eventually. Here the evidence and the common advice part company, so this one needs saying plainly. Between 60 and 80 percent of people report difficulty kneeling or an inability to kneel after a knee replacement, and the review that collected those figures concluded there is no evidence of any clinical reason why people should not kneel on a replaced knee, as long as kneeling on a rough or uneven surface is avoided, because that can damage the skin over the top and let bacteria in. It also found that a range of health professionals advise patients not to kneel, and that the reasons for that advice have not been fully investigated (Wylde and colleagues, 2019). The surgeons' own patient information puts it in one line on its total knee replacement page: kneeling is sometimes uncomfortable, but it is not harmful (OrthoInfo). Read that carefully, because it is not this page telling you to kneel. The NHS instruction to wait until your doctor says you can still stands, your team's timing still governs, and the skin reason earlier in this page is real. What it means is that if you are years down the line and still avoiding kneeling because you believe it damages the implant, that belief is worth taking to your surgeon rather than living with. The review also found no link between how far a knee bends and whether its owner reports being able to kneel, so the problem is usually not the movement. The whole of that subject, including what to kneel on and how to try it safely, belongs to kneeling after a knee replacement.
Giving up the walking aid is the mirror image of all this, and it is the one place where being careful for longer is clearly right. OrthoInfo warns that a fall in the first few weeks after surgery can damage the new knee and may lead to further surgery. Keep the aid for as long as your physio asks rather than for as long as you feel you need it, and if you are older, unsteady, or have fallen in the past year, treat this as a falls question as much as a knee question and start balance and falls prevention alongside your knee program rather than after it.
One last thing in this group, because it gets filed as being out of condition and it is not. Getting more and more tired in the days or weeks after the operation, breathless walking to the toilet or getting dressed, dizzy, racing or paler than usual is not the usual recovery, and it is a same-day call rather than something to rest through. The full wording is below.
When to get help, and how quickly
Most of this recovery is uneventful, and the few things that are not do not wait for your next appointment. The lines below are sorted on that basis, with the emergency group being a call to emergency services and the same-day group a call to your surgical team today.
Learn the fall pair, since they are the reason the caution in the first weeks is worth taking seriously at all. A fall after which you cannot put weight on the leg, or where the knee or thigh is very painful or the leg looks out of shape, is an emergency department visit and not a phone call, and you should not drive yourself. The quieter half is the one people sit on: a smaller knock that leaves the knee newly painful, swollen or bruised still needs checking the same day, even when you can walk on it, because a break in the bone around a new knee is not always obvious at first.
The sign after that arrives suddenly. Losing the ability to straighten the knee or to lift the leg straight, often with a pop or a tearing feeling, or noticing a dip just above or below the kneecap, is a same-day call, because a tendon at the front of the knee may have torn and a repair done soon works better than one done late.
The next two owe nothing to how careful you have been and everything to having had an operation. Sudden breathlessness, chest pain or coughing up blood is an emergency call even with a leg that looks perfectly normal. A calf or thigh that is newly swollen, warm or tender needs advice the same day, and so does a leg that is swelling further from day to day instead of settling. If you are on tablets or injections to lower your clot risk, there is a line below for that too, and the part to know before anything happens is the head: bang it while you are on one of those medicines and you need urgent advice even if you feel fine.
Then the slower ones, which belong on this page because a careful reader is the one most likely to explain them away. A wound that is getting redder, hotter or more painful, or still leaking in the second week. A knee whose redness, warmth or pain is not settling. New knee pain with a temperature, at any point in the years ahead, including long after everything had settled. A knee that has stopped gaining movement, or that feels unstable or gives way. And pain that had gone and has come back, month by month. A temperature is not what qualifies new pain in a new knee for that list. OrthoInfo names increased pain or stiffness in a joint that had been working well among the signs of an infection around a new joint, says the signs can be as little as mild redness and swelling, and says fever is no longer considered a sign of one. The full wording for each, and how fast each one needs answering, is below. Problems after a knee replacement takes the same signs in order of urgency and adds who to contact out of hours where you live.
Related exercise programs
Warning signs
Get emergency help now
- Emergency: since your operation, you suddenly become short of breath, you get chest pain or pain in your upper back that may be worse when you breathe in, you cough up blood, your heart is beating very fast, or you faint. Call emergency services straight away, even if your leg looks normal. These can be signs of a blood clot in the lungs (pulmonary embolism).
- Emergency: after a fall or a knock, you cannot put weight on the leg, your knee or thigh is very painful, or the leg looks out of shape or shorter than the other. Go to an emergency department straight away, and do not drive yourself. If you cannot get up, call emergency services. A broken bone around a knee replacement is rare, but it needs treatment in hospital. If a smaller fall or knock leaves the knee newly painful, swollen or bruised, even if you can still walk on it and the leg looks normal, stop the exercises, go back to your crutches or sticks and keep your full weight off that leg, and get it checked by your surgical team the same day. A break in the bone around a new knee is not always obvious at first, and walking normally on one can move the broken ends apart.
Get help today
- Same day: a calf or thigh that is newly swollen or getting more swollen, warm, tender, red or darker than usual, has swollen veins that are sore to touch, or has a throbbing or cramping pain that does not fit your injury or condition, or that feels different from normal muscle soreness after exercise. This can be a sign of a blood clot (deep vein thrombosis), especially after surgery, an injury, time in a cast or boot, a long trip or a spell of being much less mobile than usual. Get medical advice the same day. If you are also short of breath or have chest pain, call emergency services.
- Same day: swelling in the operated leg that is increasing from day to day instead of settling, including swelling spreading into your calf, ankle or foot, pain in your leg or calf away from the wound, increasing pain in your calf, or tenderness or redness above or below your knee. Get medical advice the same day. Swelling is expected after this operation, and it can be moderate to severe in the first days or weeks, but OrthoInfo asks you to tell your doctor about new or severe swelling because it can be the warning sign of a blood clot, and increasing swelling of the calf, ankle and foot, increasing calf pain, and tenderness or redness above or below the knee are all on its list of clot signs. Your clot risk does not end on the day your tablets or injections do. If you are also short of breath or have chest pain, call emergency services.
- Same day: you are taking tablets or having injections to lower your risk of a blood clot and you notice blood in your urine, black or bloody stools, bleeding gums, a nosebleed that goes on and on, bruising far beyond what the knock would explain, or you are being sick or coughing up blood. Get medical advice the same day, and do not stop the medicine on your own. Bleeding more easily is the known trade-off of these medicines (NHS), and the dose or the type may need looking at. Go to an emergency department if the bleeding will not stop, you feel faint, or you bang your head while you are taking it, even if you feel fine, because the NHS advises getting urgent advice after a head injury on medicine that thins your blood and only a hospital can scan for a bleed inside the head.
- Same day: your wound becomes more red, hot, swollen or painful, starts to leak or ooze, is still leaking in the second week or has never stopped, has pus coming out of it or its edges start to come apart, or you have a high temperature or feel hot, cold or shivery. Contact your surgical team or get medical advice the same day. Redness can be harder to see on brown or black skin. If you feel very unwell, go to an emergency department. If you have a very high or very low temperature, shivering you cannot control, you are breathing very fast or finding it hard to breathe, you are confused or your speech is slurred, your skin, lips or tongue look blue, gray, pale or blotchy (on brown or black skin this can be easier to see on the palms of the hands or soles of the feet), or you have a rash that does not fade when you press it, call emergency services, as this can be sepsis.
- Same day: since your operation, the redness, warmth, swelling or pain in your knee is not getting better or is getting worse, for example the knee pain keeps building both when you move and when you rest. Contact your surgical team or get medical advice the same day, as this can be a sign of infection around the new joint. If you feel very unwell, go to an emergency department.
- Same day: at any time after your operation, even years later, new pain in your new knee along with a high temperature or feeling hot, cold or shivery, or a knee that becomes hot, red or swollen, which counts on its own, with or without pain and with or without a temperature. Contact your surgical team or get medical advice the same day. A new joint can become infected long after the operation, and that needs treating quickly. A normal temperature is not an all clear: OrthoInfo says fever is no longer considered a sign of an infection after a joint replacement, that the signs can be as little as mild redness and swelling and sometimes there are none at all, and that increased pain or stiffness in a joint that had been working well is one of them. So do not wait for a temperature before you report new or increasing pain in your new knee to your surgical team.
- Same day: you suddenly cannot straighten your knee or lift your leg straight when you could before, often after a pop, a tearing feeling or a stumble, or you notice a dip just above or below your kneecap, or you suddenly cannot put weight on the leg, even without a fall. Keep your weight off it and contact your surgical team the same day. If you cannot reach them that day, go to an emergency department. A tendon at the front of the knee may have torn, and a repair works better when it is done soon.
- Same day: in the days or weeks after your operation you are getting more and more tired, breathless doing everyday things such as walking to the toilet or getting dressed, dizzy or lightheaded, your heart is racing, or your skin looks paler than usual. Contact your surgical team or get medical advice the same day. Tiredness and breathlessness that build up like this are not part of the usual recovery. Blood loss during and after a knee replacement can leave you short of red blood cells (anemia), which is treatable, and a slow bleed or an infection can show up the same way. If breathlessness comes on suddenly, or you get chest pain, call emergency services, as the emergency line above explains.
- Same day: a leg or foot that is getting weaker, for example your foot drags, catches on the ground or slaps down when you walk (foot drop). Get medical advice the same day. Until it has been checked, use your walking aid, hold a rail on stairs and keep off uneven ground, because a foot that catches trips you and a fall onto a new knee can damage it. If the weakness is getting worse by the hour, go to an emergency department.
- Same day: new numbness, tingling or burning in your lower leg or foot, beyond the numb patch of skin around your scar. Contact your surgical team or get medical advice the same day. If it started after a fall or an injury, or your foot or toes turn cold, pale, blue or gray, call emergency services or go to an emergency department straight away, and do not drive yourself.
- Same day: dizziness, lightheadedness, blurred vision or feeling faint when you stand up that is new for you, does not pass within a minute or two, keeps happening, or has made you fall. Sit or lie down, and get medical advice the same day. This can be a drop in blood pressure on standing (postural hypotension), a type of low blood pressure, which the NHS lists among the causes of falls, and your doctor can check it. Tell them about your medicines, because some can cause it. If it does not settle within a few minutes of sitting or lying still, call emergency services. If you faint, call emergency services, even if you come round quickly, because the NHS says to call them when someone faints while exercising or is badly hurt, and a fall onto a new knee can damage it.
- Same day: dizziness or feeling faint during or after exercise, other than the brief lightheadedness as you stand up covered in the line above, without any of the emergency signs above. Stop the exercises and get medical advice the same day. If you faint, it does not settle within a few minutes of sitting still, or you cannot stand or walk steadily, call emergency services.
Book an appointment
- Within a few days: your knee is not bending or straightening any further from week to week, is getting stiffer, or feels unstable or gives way when you stand or walk. This is not an emergency, but contact your physio or surgical team within the next few days rather than waiting for your next routine appointment, and keep using your walking aid until they have checked it. A stiff knee is easier to free up early than late: where it has to be freed up under anesthetic, doing that earlier, generally within about 6 to 12 weeks of the operation, is associated with regaining more movement than doing it later, although how much any one knee gains also depends on how stiff it was to begin with, on who is suitable and on the rehabilitation afterward. So the date you raise it matters (Hosanee and colleagues, 2026). If the knee has given way and let you fall, or it gives way on stairs, hold a rail and use your walking aid every time, and stay off stairs on your own until you have been seen.
- Within a few days: you have had a fall, even if you were not hurt, or you keep tripping, stumbling or feeling that your legs might give way. Book an appointment with your doctor within a few days and ask about a falls assessment. Tell them about every fall, even the ones where you were not hurt.
- Routine: pain in your new knee that had settled and has come back, or pain that is getting worse month by month, for example pain that starts as soon as you stand up and begin to walk. This is not an emergency, but ask your surgical team for a review, as the parts of a new joint can loosen or wear over the years. Get medical advice the same day instead, not a routine appointment, if the knee also becomes hot, red or swollen, or you have a high temperature or feel hot, cold or shivery, or the pain is building week by week rather than month by month. A new joint can become infected years after the operation, and the two can feel similar at first.
Common questions
What not to do after a knee replacement?
The NHS gives the general list, and it is short: do not kneel on the new knee until your doctor says you can, do not sit with your legs crossed for the first 6 weeks, do not stand for long periods, do not sleep with a pillow under your knee, avoid twisting your knee, bending down and reaching up as much as possible, and leave household tasks that involve lifting or moving anything heavy for the first 3 months. The NHS names vacuuming and carrying shopping as the examples of heavy. For the longer term, OrthoInfo says most surgeons advise against high-impact activities such as running, jogging and jumping. If your surgical team gave you anything that differs from this, theirs is the instruction that counts, because it was written for the operation you actually had.
How long do you have to avoid these things after a knee replacement?
Each group has its own clock. The NHS puts 6 weeks on sitting with your legs crossed and 3 months on heavy household tasks, and attaches no date at all to kneeling, which it leaves with your doctor, or to standing for long periods and twisting, which it leaves open. The high-impact advice has no end date, because it is a long-term preference and not a healing restriction. Nothing in any of that is a release form: ask at the follow-up appointment the NHS says you will have about 6 weeks after the operation, which is the natural place to put the question.
What happens if you kneel or cross your legs too soon after a knee replacement?
Usually nothing happens, and the useful move is to stop auditing it and start watching the knee. What matters is not the movement you made but whether a symptom followed it. A fall or a knock, even a small one, that leaves the knee newly painful, swollen or bruised needs your surgical team the same day, with the exercises stopped and your weight kept off that leg in the meantime. A sudden loss of being able to straighten the knee or lift the leg straight, especially after a pop or a stumble, is also a same-day call. If you broke the skin kneeling, the wound lines apply. Those warnings are below with the urgency each one needs. Absent any of them, one crossed leg or one kneel is not how a well-fixed knee replacement comes to harm, and it is still worth mentioning at your next appointment.
Can you twist your knee after a knee replacement?
The NHS asks you to avoid twisting your knee as much as possible, and it does not say why or for how long, so neither does this page. In clinic the version that makes sense of the instruction is turning your body while the foot stays planted, which is what happens when you pivot to reach a cupboard or turn away from the sink. Stepping your feet round instead costs nothing and is a habit worth building early. Ask your own team what they mean by it and when it stops applying, because they can watch you move and this page cannot.
Will I always have to be careful with a knee replacement?
Careful in one narrow sense, and no more than that. The healing restrictions end, and the general early list the NHS gives has two dates in it, 6 weeks and 3 months. What does not come with an end date is the position on high impact: OrthoInfo says most surgeons advise against running, jogging, jumping and other high-impact sport for the rest of your life, and the reason it gives is wear, not an accident. It also says that every total knee replacement implant begins to wear in its plastic spacer, that too much activity or too much weight can speed up that normal wear, and that the wear may in turn cause the knee replacement to loosen and become painful, which is the reason the advice is lifelong rather than a healing rule. Low-impact activity is not on that list. OrthoInfo tells people to walk as much as they would like, and names golf, bicycling and pickleball as preferable to high-impact activities.
Is there anything I should not be avoiding after a knee replacement?
Yes, and it is the part of this question that does real harm. Bending the knee is the work, not the risk, and a knee kept quietly straight for comfort gets stiff in a way that is far harder to undo than it was to prevent. Walking, your prescribed exercises, standing up out of chairs, and using the walking aid for as long as your team asks all belong on the do side. OrthoInfo asks people to keep going with the exercises their physical therapist or physio gave them for at least 2 months after the operation. If you are struggling to do that alone, the answer is more help and not less movement: NICE recommends supervised outpatient rehabilitation for people who are finding daily activities difficult, who have ongoing problems with function and particular needs, or who are not reaching their goals on their own.
References
- NHS. Recovering from a knee replacement. Page last reviewed 9 September 2026. https://www.nhs.uk/tests-and-treatments/knee-replacement/recovery/
- American Academy of Orthopaedic Surgeons. Total knee replacement. OrthoInfo. https://www.orthoinfo.org/en/treatment/total-knee-replacement/
- American Academy of Orthopaedic Surgeons. Activities after total knee replacement. OrthoInfo. https://www.orthoinfo.org/en/recovery/activities-after-knee-replacement/
- American Academy of Orthopaedic Surgeons. Infection after joint replacement. OrthoInfo. https://www.orthoinfo.org/en/diseases--conditions/joint-replacement-infection/
- National Institute for Health and Care Excellence. Joint replacement (primary): hip, knee and shoulder. NICE guideline NG157. Published 4 June 2020. https://www.nice.org.uk/guidance/ng157
- Wylde V, Artz N, Howells N, Blom AW. Kneeling ability after total knee replacement. EFORT Open Reviews. 2019;4(7):460-467. https://doi.org/10.1302/2058-5241.4.180085
- Polizzotti G, Lamberti A, Mancino F, Baldini A. New horizons of cementless total knee arthroplasty. Journal of Clinical Medicine. 2023;13(1):233. https://doi.org/10.3390/jcm13010233
- Wallace DA, Salem GJ, Salinas R, Powers CM. Patellofemoral joint kinetics while squatting with and without an external load. Journal of Orthopaedic and Sports Physical Therapy. 2002;32(4):141-148. https://doi.org/10.2519/jospt.2002.32.4.141
- Hosanee S, Elebo N, Sikhauli N, Pietrzak JRT. Reluctant knee: understanding and managing stiffness after total knee arthroplasty. International Orthopaedics. 2026;50(9):2337-2346. https://doi.org/10.1007/s00264-026-06905-0
- NHS. Anticoagulant medicines. Page last reviewed 9 September 2024. https://www.nhs.uk/conditions/anticoagulant-medicines/
- NHS. Falls. https://www.nhs.uk/conditions/falls/
- NHS. Low blood pressure (hypotension). Page last reviewed 11 July 2023. https://www.nhs.uk/conditions/low-blood-pressure-hypotension/
- NHS. Fainting. https://www.nhs.uk/symptoms/fainting/
- NHS. Sepsis. Page last reviewed 14 May 2026. https://www.nhs.uk/conditions/sepsis/
Written and checked by the PocketPhysio editorial team. Last updated 2026-10-17.
This page is general education, not a diagnosis or a personal treatment plan. See a physiotherapist or doctor for advice about your own situation.