How Long does Swelling Last After Knee Replacement?

Last update: April 2023
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Written by Nelly Darbois, physical therapist and scientific writer.

Swollen knee, knee edema: Are they the same thing?

In everyday language, we use the terms swollen or puffy knee to describe a knee that appears larger than normal. The medical term used for this condition is knee edema, which means the same thing.

Knee edema = Swollen knee = knee swelling = puffy knee

Swelling assessment after total knee replacement (TKR): really?

We can measure the circumference of the knee to determine the extent of the swelling. Typically, we use a measuring tape with the upper part of the patella (kneecap) as a reference point, and compare it to the other side.

In the days, weeks, or months following knee replacement surgery, there may be a difference of several centimeters between the operated knee and the healthy knee. This difference can be 2-3 cm, 5-6 cm, or even more.

This is a very common phenomenon, which does not necessarily indicate a problem.

⚠️ In most cases, measuring this difference is not really necessary because the treatment plan is not affected by the difference in volume between the two knees! It can actually cause more concern than necessary. However, some people may prefer to “monitor” this parameter and find reassurance in taking measurements.

What are the symptoms of swollen knee after replacement?

Often, the skin around the knee also undergoes some changes in color or texture. It may become:

• tight, cracked, or hard,
• shiny,
• red,
• or bruises (blue, purple, yellow) may appear. These bruises can sometimes extend from the feet to the hip.

Common symptoms of a swollen knee may also include:

• Increased size or volume of the knee or the foot or lower limb (foot and lover limb swelling after knee surgery is also common)
• Discomfort or pain in the knee joint
• Stiffness or limited range of motion in the knee
• Warmth or redness around the knee
• Fluid accumulation in the knee joint (effusion)

Although this may be concerning at times, in isolation, it is not something to be alarmed about. It is a typical development after a knee replacement surgery.

It is common for the knee to swell and change color after a knee replacement surgery. This does not at all mean that there is a problem.

Why does the knee swell after a joint replacement surgery?

It is very likely that your knee will swell after surgery. This is a normal physiological phenomenon. However, the swelling can be more significant in some people, due to various factors, including genetic predisposition.

What causes fluid on knee after knee replacement?

The swelling is caused by an accumulation of fluids in the various layers of tissue in the knee. It is related to the inflammation of the different tissues.

Inflammation triggering the swelling is a very healthy and therapeutic response! It is an automatic reaction of our immune system, inherited from our ancestors. This inflammation helps to repair damaged tissues.

It brings all the necessary substances to the damaged area through fluids to help the structures heal naturally as quickly as possible. 🚀

Generally, anti-inflammatory drugs (NSAIDs) are prescribed for the first few days after surgery. This limits the inflammatory response, but does not completely prevent it, as it is partly beneficial 🙂. Sometimes it is necessary to continue taking them, and it is often the doctor who prescribes them, sometimes at the request of your physical therapist (in France, physical therapists cannot prescribe NSAIDs).

After knee replacement surgery, there will be inflammatory responses in the knee, causing swelling and edema. This is normal and usual, and it means that your body is doing everything it can to ensure proper healing and recovery!

How much swelling is normal after knee replacement?

Don’t worry too much about the size of the swelling after knee replacement.

Even if your operated knee looks twice as big as the other one, or if the swelling lasts for several months, it’s not necessarily a cause for concern. This symptom alone isn’t enough to worry about.

But you can always talk to your physical therapist or doctor if you need some reassurance.

Risk factors

Some people may experience more swelling than others. Certain factors can affect the amount and duration of swelling. You may have more significant and prolonged swelling if:

• You have certain medical conditions like hypothyroidism, vein problems, or heart failure.
• You are overweight or obese.
• You lost a lot of blood during the surgery.
• You have weak quadriceps muscles.

(Cansabancu 2021 ; Gao 2011)

Being overweight, having certain medical conditions, and losing a lot of blood during surgery can increase the risk of developing swelling after knee replacement surgery.

How long does swelling last after knee replacement?

After an ankle sprain, the joint swells. Same thing happens when you have a knee replacement! This often causes worry and concern for people who see their knee swelling, persistent edema, or a knee that’s colored “strangely” for a long time.

However, swelling after total or unicompartmental knee replacement is a very common phenomenon. It can last for several weeks, months, and even years without being a cause for concern. While it can be a little uncomfortable, the knee pain will gradually decrease even if the swelling persists.

• Swelling is often most pronounced between the third and fifth postoperative day (or the sixth and eighth day) and often affects both lower limbs but more so the operated one. Swelling is greater above than below the knee. (Gao 2011; Loyd 2020)
• Your operated knee increases in volume by an average of about 35% compared to before the operation.
• At 3 months, on average, the volume is still increased by 11% on average. (Pua 2015) In some people, it can increase by 47% (Loyd 2020).

That’s why edema can remain relatively large even 2 or 3 months after knee replacement. This isolated sign should not be a cause for concern.

In the vast majority of cases, the knee will return to its usual volume over the course of months or years, even if you had a lot of arthritis. And if it takes time to recover, look on the bright side: you will still be able to resume all the physical and sports activities you want.

The knee can remain swollen for a long time (several weeks or months) after a replacement without it being a sign of a problem.

When should I worry about swelling after knee surgery?

Swelling after knee surgery is a very common occurrence and it’s totally normal to experience it for several months or even up to a year after the procedure. So, don’t worry too much if the swelling persists for a long time.

However, if you are concerned, it’s always a good idea to discuss it with your physical therapist or doctor. They can provide you with personalized advice and reassurance.

Instead of focusing solely on the swelling itself, it’s important to pay attention to how it’s affecting your daily activities. Are you able to move around comfortably and perform the tasks you need to do? If the answer is yes, then there’s probably no need to worry too much about the swelling.

But if it’s causing significant discomfort or limiting your mobility, then it’s definitely worth bringing up with your healthcare provider.

Overall, it’s important to remember that swelling is a common and normal part of the healing process after knee surgery. Keep an eye on it, but don’t let it consume your thoughts or actions. Focus on your overall progress and take things one day at a time.

Why is my knee still swollen 6, 8 or 9 months after TKR?

The persistence of knee swelling for 6, 8, or 9 months after surgery can be attributed to various factors, although the precise cause is not always easy to pinpoint.

Some of the factors that tend to be more common among individuals with swelling lasting more than 6 months include:

• underlying medical conditions such as hypothyroidism,
• vein problems, or heart failure, as well as being overweight or obese,
• a significant loss of blood during the surgery,
• weakened quadriceps muscles can contribute to prolonged edema.

(Cansabancu 2021; Gao 2011)

Fluid on knee 2 years after knee replacement

Yes, it can happen that fluid stay on knee 2 years or more. In fact, many people, search for information on this topic each month.

It’s not uncommon to experience fluid accumulation in the knee even years after knee replacement surgery.

However, this doesn’t mean that these people couldn’t resume their pre-surgery lives. There is no specific treatment related to knee swelling after knee replacement surgery; you can explore treatments for knee swelling in general.

What reduces swelling after knee replacement?

I totally get that you’re looking for a way to reduce the swelling in your knee as quickly as possible. It’s natural to be worried about it looking different from your other knee or even feeling uncomfortable or unattractive.

However, I have to be honest with you: we don’t necessarily have a “miracle” solution or even a consistently effective one for significantly speeding up the reduction of swelling.

❌ Ultrasound therapy and other physiotherapy methods (such as cold therapy, TENS electrotherapy), massage, manual lymphatic drainage, compression therapy (compression stockings), and kinesiology taping are not effective in the short or long term for reducing swelling.

Massage does not allow for a lasting reduction in swelling, but you can self-massage if you find it relieves discomfort and temporarily decreases swelling.

✅ The following tips may provide short-term relief for edema, but once they’re no longer applied, the swelling is likely to return:

• wearing compression stockings or compression socks with a class II rating (see on Amazon). Although compression stockings can reduce swelling in healthy individuals, they don’t appear to reduce swelling in people who have had knee replacement surgery ;
• elevating your leg (with your legs and feet above your hip and heart level)
• limiting the time spent in static positions, such as standing (while doing household chores) or sitting (during meals or computer work). It’s important to alternate between walking and elevating your leg.

Does walking reduce swelling after knee replacement?

Yes, walking can help reduce swelling after knee replacement surgery.

• When you walk, your muscles contract and relax, which helps to pump fluid and blood through your body. This increased circulation can help to reduce swelling in the affected knee.

• Additionally, walking helps to improve range of motion and prevent stiffness in the joint, which can also contribute to reduced swelling over time.
• When you engage in exercise, your body releases hormones that can help to reduce inflammation and swelling throughout your body.

Should I wait until my swelling and pain are completely gone before resuming my activities?

Important and often counterintuitive thing to note: just because a knee is swollen doesn’t necessarily mean it will hinder walking or even sports activities!

In fact, people with more knee swelling tend to do just as well or even better than those with less or no swelling.

This holds true not only in the days immediately following surgery, but also for longer periods of time.

Swelling will gradually decrease over days, weeks, or even months, regardless of what you do. Elevating the leg, avoiding static sitting or standing positions, wearing compression stockings… all of these things can help reduce swelling.

What is the recovery time after a knee replacement surgery?

Here are some figures on the average recovery time for various things after a knee replacement.

Keep in mind that these are average numbers: some people will recover much faster, while others may take longer, without it being a cause for concern.

Recovering flexion and extension

From the day after the knee replacement surgery, a physiotherapist will likely help you move your knee a little, especially in flexion and extension. They should also show you movements you can do on your own to maintain or even gain some amplitude. On average, knee flexion is:

• 100° 2 weeks after surgery;
• It increases mainly during the first 12 weeks (3 months), and very little after 26 weeks (6 months);
• 117° 1 year after. (Mehta 2020)

These amplitudes allow you to resume most sports activities.

Recovering everyday movements

It’s difficult to predict with precision how quickly you’ll be able to resume your daily activities. We don’t know what makes some people recover better or faster than others. Even if you had a lot of knee arthritis and were very uncomfortable before the operation, you can still recover well.

Here are the average recovery times I observe in my patients (and I discuss them further in my article on the recovery time after a knee replacement – coming soon!):

Stage	Recovery Time
You have much less pain	A few days to a few weeks
Swelling and bruises disappear	A few days to a few weeks
You walk with crutches or a walker	From the next day
You walk without crutches or canes	After 1 to 2 months
You can get back into a bathtub without special equipment	After 1 to 2 months
You can gradually resume sports (starting with cycling, then other activities)	From 1 to 3 months

Be reassured by the figures available on resuming sports after total knee replacement:

• 88% of those who have had surgery return to their pre-surgery level of exercise and sports activity;
• 10 years after the prosthesis is implanted, 70% continue to participate in sports. (Oljaca 2018) ;
• there are no permanent restrictions after knee replacement!

Knee replacement swelling after 2 years: what to do?

Even though knee swelling disappears in a few days for most people after knee replacement, it’s not always the case. A minority of individuals still experience swelling even several years after the surgery.

I’m sharing this not to cause concern but to reassure you. It’s a known occurrence and doesn’t necessarily indicate a complication or rejection of the replacement.

Swelling doesn’t always result in pain or inconvenience in daily life.

What should you do if you’ve had this swelling that won’t go away for 1 year, 2 years, or more? I invite you to read my article on treatments for knee swelling to help you navigate through it.

Rest assured that it’s not a sign of complications or rejection of your replacement!

And remember, you’re not alone: hundreds of people search Google every month for information on knee swelling two years after a knee replacement.

Pictures of swelling after knee replacement

I know that people often request pictures of swelling for comparison. Here are some pictures that show how knees can react very differently after knee replacement surgery!