Swelling After Knee Replacement: What’s Normal and How to Reduce It

Note: This article is general information, not medical advice. Always follow the advice of your surgeon and hospital team.

The short answer: swelling after knee replacement is normal. It can affect your knee, lower leg and ankle for six months or even up to a year. It tends to build up when you are active and ease when you raise your leg. You can reduce it with regular elevation, short ice sessions, gentle movement and pacing. Get urgent advice for calf pain or breathlessness.

Most people expect some pain after a new knee. Fewer expect it to stay puffy for months, or for the ankle to balloon by teatime. This guide explains what normal swelling looks like, how long it tends to last, and what you can do at home to settle it. It sits within our wider home rehab after surgery in Birmingham guide, which covers the full recovery picture.

Is swelling after knee replacement normal?

Yes. Swelling is part of how your body heals. During surgery, the bone, joint lining and soft tissue are all disturbed. Your body sends extra fluid and blood to the area to repair it. This is called inflammation, and the build-up of fluid is called oedema (say “ee-dee-ma”).

The University Hospitals Birmingham NHS Foundation Trust knee guide explains that it is normal for the knee, and often the whole leg, to swell after surgery. It should settle when you raise your leg. Many people having surgery at UHB hospitals or the Royal Orthopaedic Hospital are given an enhanced recovery plan. That means getting up and moving soon after the operation, which helps with swelling too.

Bruising often spreads down the shin and into the foot over the first two weeks. It looks dramatic but is common.

This happens after both a total knee replacement and a partial knee replacement, though everyone heals at their own pace.

How long swelling lasts

How long does swelling last after knee replacement? Longer than most people think. The knee is usually at its most swollen in the first few weeks, then slowly settles, though it often returns after a busy day.

Did you know? “Swelling in your knee, lower leg and ankle can be expected for 6 months or even up to a year post operation.” Source: West Suffolk NHS Foundation Trust, Advice following total knee replacements for remote patients (issue date 27/10/21). Read the leaflet

So a puffy knee at three months does not mean something has gone wrong. What matters is the trend: is it slowly getting better week by week?

Typical swelling timeline

[Diagram: Illustrative line diagram, not measured data. X-axis: time after surgery (week 1, week 2, week 6, month 3, month 6, month 12). Y-axis: “how swollen the knee feels” (high to low). The line starts high in weeks 1 to 2, falls steadily to month 3, then tapers gently towards low at months 6 to 12, with small bumps marked “busy days”. Caption: “Conceptual timeline based on West Suffolk NHS Foundation Trust’s 6 months to 1 year guidance. Your own pattern may differ.”]

Normal swelling vs warning signs

Most swelling is harmless. But a few signs can point to a blood clot in the leg (DVT, or deep vein thrombosis), a clot that has moved to the lungs, or a wound infection. This table helps you tell the difference.

Sign	Probably normal	Get checked
Timing	Worse in the evening, better after rest and elevation	Getting steadily worse over several days, even with rest
One leg or both	Operated leg swollen, other leg fine	Sudden new swelling in the calf, or both legs swelling a lot
Calf	Mild ache from walking more	Calf pain, tenderness, tightness or redness
Wound	Dry, slowly healing, mild pinkness at the edges	Spreading redness, oozing, a bad smell or the wound opening
Heat	Knee feels a little warm	Knee very hot and much more painful than yesterday
Temperature	Normal temperature	Fever, shivers or feeling generally unwell
Breathing	Normal	Shortness of breath or chest pain

When to get urgent help - Call 999 or go to A&E if you have chest pain, sudden shortness of breath, or you cough up blood. These can be signs of a clot in the lungs. - Call NHS 111 or your hospital ward straight away if your calf is painful, swollen, warm or red, or your wound looks infected or you have a high temperature. - Contact your GP or surgical team if swelling is not improving at all after several weeks, or it is stopping you from bending the knee.

How to reduce swelling at home

These steps are simple. Doing them a few times a day, every day, is what makes the difference.

• Raise your leg. Lie down with your knee and ankle level with, or slightly above, your hip. Propping your foot on a footstool while sitting upright is not enough.
• Use ice, wrapped. Short sessions can ease swelling and pain. See the table below.
• Do circulation exercises. Ankle pumps (pointing your foot up and down) and tightening your thigh muscle help push fluid back up the leg. Aim for a set every hour while awake.
• Avoid standing still for long. Fluid pools in the ankle. Sit down when you can.
• Pace your day. Split jobs into short chunks. Walk, rest, then walk again, rather than one long outing.
• Wear compression stockings if advised. Some hospitals give these to lower the risk of DVT. Wear them as long as your team says.

Ankle swelling after knee replacement is very common, especially in the afternoon. It often settles by morning. If one ankle is painful, hot and swollen all day, check with your team.

If you would like help building this into a daily routine, our knee physio at home service can set it up with you.

Ice guidance at a glance

West Suffolk NHS Foundation Trust advises that “Ice can be used three or four times per day, for up to 10 minutes at a time.”

How often	How long	How	Avoid if
3 or 4 times a day	Up to 10 minutes	Ice pack or frozen peas wrapped in a damp tea towel, with leg raised	Skin is numb, broken or has poor feeling; you have circulation problems; your team has told you not to

Never put ice on bare skin. For a fuller look at whether to use ice or heat after surgery, read our short guide.

Need help with recovery? Our HCPC-registered physios offer post-surgery physio at home across Birmingham. First visit £110, pay after the visit. Book a home visit.

Swelling and your exercises

Exercise and swelling have a two-way link. Movement helps fluid drain away, but doing too much in one go can make the knee swell more. The aim is to find your sweet spot.

A useful rule: extra swelling that settles by the next morning is usually fine. If the knee is much bigger and stiffer the next day, drop back a little, then build up again.

Swelling also affects range of movement, which means how far you can bend and straighten the knee. A very puffy knee is harder to bend. That is why many physios ask you to elevate and ice before or after your bending exercises.

The way you lie can affect swelling overnight too. Our guide to the best sleeping positions after knee replacement has simple tips. Once things settle, our guide to driving after knee surgery covers the next step. You can also read about physiotherapy at home after knee replacement for the wider exercise plan.

In a first home visit, the physio will usually measure how far your knee bends, look at the swelling in both legs, and watch you walk and climb the stairs. They may then change how many repetitions you do, add rest breaks, and show you how to set up pillows for elevation in your own room.

Some physios also use gentle massage that moves fluid towards the body (lymphatic drainage). Ask if it suits you.

Key takeaways

• Swelling is normal and can last six months to a year.
• It usually gets bigger with activity and smaller with rest and elevation.
• Raise your knee and ankle above hip level, use wrapped ice for up to 10 minutes, and do ankle pumps often.
• Calf pain, chest pain, breathlessness, fever or a red, oozing wound need urgent advice.

Frequently asked questions

How long does swelling last after total knee replacement?

Swelling can last six months or even up to a year after a total knee replacement, according to West Suffolk NHS Foundation Trust. It is usually worst in the first few weeks, then slowly eases. Many people notice mild puffiness after a busy day for several months. Look for a gradual improvement rather than a fixed date.

Is swelling after knee replacement normal months later?

Yes, mild swelling months later is common, especially after walking, gardening or long periods of standing. It should go down when you rest with your leg raised. If swelling is getting worse rather than better, or comes with heat, redness or new pain, ask your GP or surgical team to check it.

When should I worry about swelling after knee replacement?

Worry if you have calf pain or tenderness, swelling that keeps increasing, a hot red wound, fever, chest pain or breathlessness. These can be signs of a blood clot or infection. Call 999 for chest pain or breathing problems. For calf or wound concerns, call NHS 111 or your ward the same day.

Is foot swelling normal after knee replacement?

Yes, foot and ankle swelling is common because fluid drains downwards with gravity. It is often worse in the evening and better in the morning. Raise your leg above hip level and keep doing ankle pumps. If one foot or ankle is painful, red and swollen all the time, get it checked.

How can I reduce swelling after knee replacement at home?

Lie with your knee and ankle above hip level several times a day. Use wrapped ice for up to 10 minutes, three or four times a day. Do ankle pumps every hour, avoid standing still for long, and pace your activity. Wear compression stockings if your hospital gave them to you.

Does physio help with swelling?

Physio can help by setting the right amount of exercise, showing you how to elevate properly, and tracking your progress. A physio can spot when swelling is holding back your knee bend. They cannot promise how fast swelling will go, as healing varies, but many people find guided pacing makes daily swelling easier to manage.

Conclusion: get help with swelling after knee replacement

A puffy knee for months is frustrating, but for most people it is normal healing. Keep raising your leg, use ice sensibly, move little and often, and watch for warning signs. If swelling after knee replacement is slowing your progress, a physio can adjust your plan in your own home. For the bigger picture, go back to our surgery recovery guide for Birmingham or see our home physio in Birmingham page. FlexAura physios are HCPC-registered, enhanced DBS-checked and insured.

• Book a home visit: first visit £110 (60 min), follow-ups £99, pay after the visit and no GP referral needed. Book a post-op visit.
• Not sure yet? Try a 30-minute online consultation for £45, or WhatsApp us on 07782 610 633.

Sources

• West Suffolk NHS Foundation Trust, Advice following total knee replacements for remote patients (issue date 27/10/21): https://www.wsh.nhs.uk/CMS-Documents/Patient-leaflets/Physiotherapy/6764-1-Total-knee-replacement-physio-advice-for-remote-patients.pdf
• University Hospitals Birmingham NHS Foundation Trust, Supporting your Enhanced Recovery: Patient Guide for Knees: https://www.uhb.nhs.uk/media/p4kgjhbf/surgerykneeguide.pdf