Why does your foot swell after knee surgery? (+1 factors)

In this article, we will discuss why your feet swell after knee surgery. We will also discuss other factors which may cause swelling of the foot after knee surgery. Some useful tips are also included to reduce the degree of swelling after knee surgery.

Why does your foot swell after knee surgery?

Your foot may swell after a knee surgery due to the accumulation of fluid, known as oedema. This occurs due to the manipulation of the knee joint during surgery which often causes trauma to the adjoining tissues.

Trauma may lead to the drainage of fluid in the lower limbs, including the feet. Foot swelling after knee surgery is a normal condition. You may experience moderate to severe swelling and pain during the first few weeks.

Foot swelling begins to decrease over the following weeks and months. Sometimes foot swelling can last up to six months of knee surgery, although it is considered normal. Consult your doctor if the problems persist for a longer time.

What does research suggest?

In one of the case reports, it was established that patients treated by an orthopaedic surgeon (n=61) who used drains and performed knee surgery in a shorter time had the lowest incidence of developing swelling in the feet (2).

In another study, it was established that if ankle surgeries are performed without a tourniquet, the incidence of swelling and pain in the foot is significantly reduced. The hospital stay length also becomes shorter (3). 

In another case report, 116 patients had venous insufficiency in the lower extremity vein after knee surgery. The pre-operative great saphenous diameter (GSV) and GSV reflux duration (>1.23 seconds) were the best predictors of swelling after knee surgery (4).

What other factors may cause foot swelling after knee surgery?

Some other factors may cause foot swelling after knee surgery, including:

Factor Reason
Liver disease Liver diseases, such as fatty liver and liver cirrhosis, can cause swelling of the feet in addition to abdominal bloating, yellowing of the skin, and fatigue.
Kidney dysfunction Decreased kidney function causes retention of sodium in your body. This leads to swelling of the feet and ankles.
Pregnancy Total blood volume usually increases during pregnancy to support the development and growth of the baby. This causes swelling of the lower limb and feet.
Sciatica The myelin sheath around the sciatic nerve may be damaged if the pressure on the nerve continues for a long time. This may cause leakage of fluid around the compressed nerve, subsequently leading to foot swelling (5).
Obesity Due to excessive pressure on the foot, the degree of foot swelling is more common in obese patients, especially after knee surgery (6). 
Varicose veins Twisting of varicose veins may cause swelling in feet and ankles. Varicose veins may also cause pain, aching, and discomfort.

How to reduce foot swelling after knee surgery?

Although swelling after knee surgery is not a life-threatening condition itself and serves an important purpose in the immune system and inflammatory chain of the healing process, excessive swelling may cause deep vein thrombosis and the formation of clots.

Elevate your legs

You should elevate your legs above your heart level gently to reduce the degree of foot swelling. Elevation of the legs improves fluid circulation from the feet and legs to the rest of the body. 


You should limit your intake of salt as it may increase fluid accumulation and oedema in the foot area. You should also increase your intake of water to help your foot and ankle mobility to reduce swelling at that site.

Eat fruits, leafy vegetables, berries and nuts. The extra water present in fruits and vegetables helps to flush out excess water from the body. They also help to improve your overall health after knee surgery.

Nuts, green vegetables, dark chocolate, and milk are good sources of magnesium. Magnesium helps to limit water retention. Your doctor may also prescribe magnesium supplements to help reduce swelling in your feet.

Use ice packs

You should use regular ice packs after knee surgery to reduce swelling and fluid accumulation. Applying an ice pack at the affected site, including the feet, constricts the blood vessels, reducing the flow of fluid in that area.


Some patients may be advised to take blood-thinning agents such as aspirin and enoxaparin to reduce the likelihood of blood clot formation after knee surgery. According to research, blood clots are one of the reasons for foot swelling after knee surgery (6).

Your doctor may also prescribe you painkillers and anti-inflammatory drugs, such as acetaminophen, ketamine, ibuprofen and meloxicam after knee surgery. You may take naproxen if you are allergic to ibuprofen.

It is not uncommon for patients to experience oedema, swelling, and pain after knee surgery. However, I would suggest you discuss your symptoms with an orthopaedic surgeon if foot swelling begins to affect your quality of life.

As a pharmacist, I often advise compression stockings for swollen feet. They are easily available at the pharmacy. You should avoid exercising or putting undue pressure on your knee and foot as it may increase swelling and pain.

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Christensen LM, Arnesen CE, Möller S, Hyldig N. The effect of compression therapy on post-surgical swelling and pain after total knee arthroplasty. International Journal of Orthopaedic and Trauma Nursing. 2021 Apr 1;41:100815. https://www.sciencedirect.com/science/article/abs/pii/S1878124120301210


Garrett BR, Walters J. Knee pain, swelling and stiffness after total knee replacement: a survey of South African knee surgeons. SA Orthopaedic Journal. 2010 Jan;9(2):59-66. http://www.scielo.org.za/scielo.php?pid=S1681-150X2010000200008&script=sci_arttext


Smith TO, Hing CB. The efficacy of the tourniquet in foot and ankle surgery? A systematic review and meta-analysis. Foot and ankle surgery. 2010 Mar 1;16(1):3-8. https://www.sciencedirect.com/science/article/abs/pii/S1268773109000368


Cansabuncu G, Gumus F. Pre-operative predictors of lower extremity swelling following total knee arthroplasty in patients with venous insufficiency and osteoarthritis. International Orthopaedics. 2021 Oct;45:2561-7. https://link.springer.com/article/10.1007/s00264-020-04888-0


Chu EC, Wong JT. Subsiding of Dependent Oedema Following Chiropractic Adjustment for Discogenic Sciatica. European Journal of Molecular & Clinical Medicine. 2018 Mar;5(1):1-4. https://d1wqtxts1xzle7.cloudfront.net/56355567/ejmcm-250-chu-libre.pdf?1524118393=&response-content-disposition=inline%3B+filename%3DSubsiding_of_Dependent_Oedema_Following.pdf&Expires=1703945206&Signature=XG5hv4dWa53m~n7uuPPvr2siuRLtRS6OjetiZ9jHS7cfMh5QriQ-uQZ-TAgtHdBoKSq5j1Fx4dIVTsprJCyHugkWX6DLYfJn46vPgSr-nROPDHvPJ0lXNXTaufjSJHdMq1VDEw6mPJGTlQXix4fKzKNSRRczaJhzUSCR-YaThQvQgOggKp0sZRzyR4ZGqUe9hSo6pfR9F9rAiWduBxE1SWBZbUwuySE9JFeaaUvcU3e0npqtmGWSQClj8JeSnXE955cfKkm~AH1flBQyUKQNzkOz~wbJR2xFhrKA~URzD–Gdb5OwFLdlkmKzyupojo-vmhJBTmXFL1qYw~ZnoehxA__&Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA


Gao FQ, Li ZJ, Zhang K, David H, Liu ZJ. Risk factors for lower limb swelling after primary total knee arthroplasty. Chinese medical journal. 2011 Dec 5;124(23):3896-9. https://pubmed.ncbi.nlm.nih.gov/22340316