Swelling After Knee Surgery: What Happens and How to Manage It

If you’ve just had knee surgery, a puffy knee is probably the first thing you notice. It can feel alarming, but a certain amount of swelling is part of the body’s natural healing process. The good news is that most of the swelling can be controlled with simple, everyday actions.

Why swelling shows up after knee surgery

When the surgeon works on your knee, blood vessels, cartilage, and surrounding tissue get disturbed. Your body reacts by sending extra blood and fluid to the area – that’s what creates the swelling. In the first 48‑72 hours the knee may look almost the size of a small beach ball. This is when the “worst day” after a knee replacement often hits, as described in our article "Worst Day After Knee Replacement".

Inflammation also brings pain‑relieving chemicals and helps repair tissue, so a little swelling actually supports healing. Problems arise when the swelling is excessive, lasts longer than a week, or is accompanied by fever, foul‑smelling discharge, or a sudden sharp pain. Those signs mean you should call your surgeon right away.

Practical ways to keep swelling down

Below are the most effective, doctor‑approved tricks you can start today.

1. Ice it regularly. Apply a cold pack for 15‑20 minutes every 2‑3 hours during the first 48 hours. Use a thin towel between the pack and skin to avoid frostbite. Ice reduces blood flow to the area, which cuts down fluid buildup.

2. Elevate the leg. Keep your knee above heart level whenever you’re sitting or lying down. A stack of pillows works fine. Elevation encourages fluid to drain back toward the torso, lessening the puffiness.

3. Gentle compression. An elastic knee sleeve or wrap can provide mild pressure that stops fluid from pooling. Make sure it’s snug but not so tight that it hurts or cuts off circulation.

4. Move smartly. Simple ankle pumps, toe curls, and short, pain‑free knee bends keep the joint fluid moving. Our guide "Safe Showering After Knee Replacement" explains how to do low‑impact moves while you’re getting ready for a rinse.

5. Take prescribed meds. Anti‑inflammatories like ibuprofen or the medication your doctor gave you can calm swelling. Take them exactly as directed; over‑use can cause stomach upset.

6. Stay hydrated. Drinking water helps your body flush excess fluid. Aim for at least 8 glasses a day unless your doctor tells you otherwise.

7. Watch your diet. Salt makes your body hold onto water, so cut back on salty snacks and processed foods during the first two weeks.

8. Know when to rest. Rest is essential, but prolonged bed‑rest can worsen swelling. Get up to walk short distances as soon as your surgeon gives the green light. If you’re unsure, check our article "Driving After Knee Surgery" for guidance on safe activity levels.

Most patients see a noticeable drop in swelling after the first week, and it keeps improving over the next three to four weeks. If swelling persists beyond a month, or you notice new redness, warmth, or a fever, contact your healthcare team – it could be an infection.

Swelling after knee surgery may feel uncomfortable, but with ice, elevation, movement, and the right meds you can keep it under control and stay on track for a speedy recovery.