Some swelling after a knee replacement is completely normal. Keeping it under control is one of the most useful things you can do — it eases pain, helps you bend the knee, and moves your recovery along.
Surgery is a controlled injury, and the body responds the way it does to any injury: with inflammation. Fluid shifts out of the blood vessels into the tissues around the knee, and the body's drainage system — the veins and lymphatic vessels — needs time to clear it. That is why the leg feels tight, warm and heavy in the early weeks.
Swelling usually peaks in the first week or so and then slowly settles. A little puffiness can linger for two to three months, and that is normal. Everyone's leg drains at its own pace, so do not compare yourself too closely with others.
Swelling is not just cosmetic. A tight, fluid-filled knee is a painful knee, and it is harder to bend and straighten. Left unchecked, swelling can slow your range of motion and make the muscles feel weak. The good news is that a few simple habits, done consistently through the day, make a real difference.
For the first two weeks especially, build your day around these four habits. Think little and often rather than one big effort.
Lie down and prop the whole leg up so the foot is higher than the heart — an easy way to remember it is 'toes above the nose'. Support the calf, not just the heel, and keep the knee fairly straight. Aim for around 40 minutes in every hour during the first 10–14 days, and elevate whenever the leg feels tight.
Cold reduces both swelling and pain. Use an ice pack or a cold-therapy wrap over a thin towel — never directly on the skin — for up to about 40 minutes at a time, several times a day in the first couple of weeks. It works well combined with elevation: ice while the leg is up.
Your calf and thigh muscles act as a pump that pushes fluid out of the leg, so gentle, frequent movement is one of your best tools against swelling. Every hour while you are awake, do a set of ankle pumps (point and flex the foot), a few heel slides, and a short walk of a few steps. Move often, but let pain and swelling be your guide — you should not be sore for hours afterwards.
If your care team has given you a compression garment or an easy-to-fasten wrap that runs from foot to thigh, wear it as advised. Gentle, even compression supports the tissues and helps the leg drain. Put it on before you get up and swelling builds, and follow the specific instructions you were given rather than reaching for old-style tight stockings.
Activity is good, but too much too soon makes the leg swell more. Increase your walking and steps gradually week by week, rest with the leg up between efforts, and expect the knee to be more swollen in the evening than the morning — that is a normal sign to ease off, not to push harder. Be cautious about returning to a busy job or long periods on your feet before your team says you are ready.
Some swelling is expected. But contact your care team promptly if you notice:
If something worries you, contact your care team — or emergency services if it is urgent.