An orthopedic surgeon explains why swelling of the surgical leg (total knee replacement) goes down overnight and then seemingly balloons up after awakening.

Following a total knee replacement, the patient may notice that the initial swelling subsides as the hours after the surgery pass.

But then, come next morning, the leg looks bigger than ever, all puffed up.

The patient may then be alarmed over the possibility of a blood clot (deep vein thrombosis).

A DVT is an alarming problem because at any moment, a piece of the blood clot (or the whole thing) could dislodge and in seconds get into the lungs and cause a life threatening pulmonary embolus.

Swelling after a Total Knee Replacement

“Swelling is a function of circulation and fluid pressure,” begins Marc W. Hungerford, MD, Chief of Orthopedics at Mercy Medical Center and Director of Joint Replacement and Reconstruction at Mercy.

“After a total knee replacement the circulation to the knee is increased because of the body’s healing response.

“When you are standing or sitting during the day, the leg is in a dependent position and the pressure in the blood vessels is increased.

“When sleeping at night, the leg is at the same level relative to the rest of the body and the pressure decreases.  This allows the pressure and swelling to go down.”

But then once you’re awake — and up and about — you may see that the leg appears to be swelling more.

Following TKR, the patient is urged to get up and about as soon as possible, not only to help prevent a blood clot, but to hastily get the joint acquainted with its new device. The sooner the better.

Nurses will check both legs of the patient throughout the day to make sure that the swelling is par for the course rather than suspicious for a DVT.

Over 600,000 total knee replacements are performed in the United States every year!

Dr. Hungerford was the first orthopedic surgeon in Maryland to perform MAKOplasty, a minimally invasive partial knee procedure powered by the RIO® Robotic Arm Technology.
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.  


Top image: Dave Haygarth/CreativeCommons