There are four main conditions that can cause legs to swell after surgery.

“There are a number of reasons for swollen legs post-operatively,” says Darren Klass, MD, clinical instructor of interventional radiology at the University of British Columbia and the Vancouver Coastal Health Association.

“The majority of the causes for this is fluid leaking into the soft tissues due to low protein in the blood, poor heart function, deep vein thrombosis, lack of mobility.”

Surgery that causes swollen legs need not involve the lower part of the body.

Coronary bypass surgery can leave both legs quite bloated.

DVT not the Leading Cause in Bilateral Swelling

“Unless the swelling is only on one side, the chance of this being a deep vein thrombosis is less than other causes,” says Dr. Klass.

“A deep vein thrombosis may not cause swelling of the leg initially and patients may be completely asymptomatic. It is only when the return of blood to the heart from the legs becomes compromised, do we see swelling from DVT.”

The swelling in the one leg may not be noticeable at first. But if the patient believes that the lower leg is looking just a little bit bigger than the other, they should point this out to their nurse and doctor.

If a DVT is suspected, a bedside ultrasound will be taken of the leg. It will immediately show if there is a blood clot.

If the result is negative, this is no reason to let your guard down. Do keep monitoring your legs, since a DVT may still develop.

Other Symptoms of DVT

Some hospitals will make sure that no matter what kind of surgery, the patient will postoperatively have on pneumatic compression devices for their liower legs.

These deliver intermittent compressing motions that help keep the blood from pooling.

To further  help prevent a blood clot, some hospitals will mandate that all patients receive a daily injection of the blood thinner heparin.

Other signs of a deep vein thrombosis are reddish or purple discoloration of the leg, tenderness, cramping or pain.

If both legs are swollen soon after surgery but feel fine and are not discolored, the patient should always be DVT-conscious.

Dr. Klass specializes in interventional oncology, aortic intervention, PVD, venous disease and venous access. He has been inducted into The Leading Physicians of the World, published by the International Association of HealthCare Professionals.
Lorra Garrick has been covering medical, fitness and cybersecurity topics for many years, having written thousands of articles for print magazines and websites, including as a ghostwriter. She’s also a former ACE-certified personal trainer.  


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