Blood Clot Prevention After Foot Surgery: What to Know

Quick answer: A blood clot in the leg (deep vein thrombosis, or DVT) is uncommon after foot and ankle surgery: in two large studies, about 1 in 100 patients was diagnosed with a clot in the leg or lungs. The risk is higher after ankle and lower-leg surgery than after forefoot surgery, and higher if you have had a clot before, have an inherited clotting disorder, take estrogen, or spend more than two weeks in a cast or boot without putting weight on the foot. Prevention comes down to moving your calf every hour, getting up as soon as your surgeon allows and, for higher-risk patients, a blood thinner. A painful, swollen calf needs a call to your surgeon the same day; chest pain or sudden shortness of breath needs 911.

Who Is Actually at Risk After Foot and Ankle Surgery

Every surgery makes the blood a little more likely to clot for a few weeks, and foot surgery adds a second problem: your calf muscle is the pump that pushes blood back up the leg, and a cast, a boot and time off your feet all slow that pump down. Even so, most people never form a clot. Before surgery we go over a short list of risk factors with every patient, because a few of them account for most clots:

• A previous DVT or pulmonary embolism. This is the strongest single warning sign. Tell your surgeon even if it happened years ago.
• An inherited clotting disorder, such as Factor V Leiden. In a large 2024 study of 301,256 foot and ankle patients, about 4 in 100 people with a known clotting disorder developed a clot, roughly four times the overall rate.
• Where the surgery is, and how long you are off your feet. In the same study, clots were least common after forefoot surgery (0.7%) and most common after ankle and lower-leg procedures (1.8%). Spending more than two weeks in a cast or boot without putting weight on the foot also raises the risk, which is why an Achilles tendon repair or an ankle fracture repair carries more risk than a bunion or hammertoe correction you can walk on in a surgical shoe within days.
• Estrogen. Birth control pills and hormone replacement both raise clotting risk. Ask your surgeon before surgery whether to pause them rather than stopping them on your own.
• Age 65 or older, significant extra weight, active cancer or other serious medical conditions, and a long car or plane trip soon after surgery.

Having one of these does not mean you will get a clot. The more of them you have, the more likely your surgeon is to add a blood thinner to your plan.

How We Prevent Clots After Foot Surgery

1. Calf pumps every hour you are awake. Pull your toes up toward your shin and push them down, 20 times. If your ankle is in a cast, tighten your calf as if you were pressing a gas pedal, unless your surgeon has told you otherwise (for example, after an Achilles tendon repair). It takes a minute and keeps the calf pump working.
2. Get up as soon as your surgeon allows. Short trips around the house on crutches or a knee scooter keep blood moving far better than a day on the couch. Elevate the operated foot when you sit, but do not sit for hours without moving.
3. Drink enough water and go easy on alcohol, which dehydrates you.
4. Avoid long trips for the first few weeks. If you cannot, stop every one to two hours, do your calf pumps and move around as much as your surgeon allows.
5. If you were given a blood thinner, take it exactly as prescribed. Patients at higher risk are usually given aspirin, a daily injection or a pill such as rivaroxaban or apixaban for a set number of weeks. Which one, and for how long, depends on your clot risk and your bleeding risk, so never start, stop or change one on your own.

How Long Does the Risk Last?

The risk is highest while you are least mobile, but it does not end on a fixed date. In the 2024 study, about a third of clots (31.9%) were found in the first two weeks after surgery, and nearly as many (29.2%) after six weeks. Keep up your calf pumps and walking until you are back on your feet normally, and take the warning signs below seriously even late in your recovery.

Early Warning Signs of a Blood Clot After Foot Surgery

The hard part is telling a clot from ordinary post-surgical swelling. Normal swelling sits in the foot and ankle, is worse at the end of the day and goes down when you lie down with the foot above your heart. Early DVT is often subtle, and some clots cause no symptoms at all. Watch for:

• A calf that feels tight, heavy or crampy and does not settle, or pain in the calf rather than at the incision.
• Swelling that spreads above the ankle into the calf or the whole leg and does not go down with elevation.
• Warmth, redness or a bluish color over the calf, or veins that look more visible than on the other leg.

Any of those: call your surgeon’s office the same day (urgent care or the emergency room after hours). An ultrasound of the leg confirms or rules out a clot quickly, and it is far better to have a normal scan than to wait.

Call 911 for sudden shortness of breath, chest pain that is worse when you breathe in, a racing heartbeat, coughing up blood or fainting. Those are signs that a clot may have traveled to the lungs (a pulmonary embolism). Do not drive yourself.

What Happens If a Clot Is Found

A confirmed DVT is treated with blood-thinning medication, usually for about three months, coordinated between your surgeon and your primary care doctor. The medicine does not dissolve the clot directly; it stops the clot from growing and lowers the chance that a piece breaks off and travels to the lungs while your body clears it. Most people who are treated promptly recover well, and the foot surgery recovery usually continues as planned.

Having surgery with us? Bring a list of your medicines, including any birth control or hormone pills, and tell us about any past blood clot at your pre-operative visit. After surgery, if you notice any of the warning signs above, call our office at (810) 206-1402 the same day.

Sources

• Richey JM, Ritterman Weintraub ML, Schuberth JM. Incidence and risk factors of symptomatic venous thromboembolism following foot and ankle surgery. Foot Ankle Int. 2019.
• Heo KY, Karzon A, Manz W, Kadakia RJ, Bariteau JT, Coleman MM. Venous thromboembolism in outpatient elective foot and ankle procedure patients: who is at risk? Foot Ankle Spec. 2026;19(4):341-354 (published online 2024).
• American Academy of Orthopaedic Surgeons, OrthoInfo. Deep Vein Thrombosis.

More questions patients ask

How common are blood clots after foot surgery?

Uncommon. In two large studies of foot and ankle surgery patients (22,486 and 301,256 people), about 1 in 100 was diagnosed with a blood clot in the leg or lungs. The risk is higher after ankle and lower-leg surgery than after forefoot surgery, and in people who have had a clot before, have an inherited clotting disorder, take estrogen, or spend more than two weeks off their feet in a cast or boot.

Do I need a blood thinner after foot surgery?

Not always. Your surgeon weighs your risk of a clot against your risk of bleeding. Many lower-risk patients who are walking within days need only calf exercises and early movement. Patients at higher risk, such as those who will be off their feet in a cast for weeks or who have had a clot before, are often given aspirin, a daily injection or a pill for a few weeks. If you were prescribed one, take it exactly as directed and do not stop early without asking.

Is calf pain after foot surgery normal?

Mild aching from crutches, a boot or a change in the way you walk is common and settles with rest. Calf pain that is constant or getting worse, especially with swelling above the ankle, warmth or redness, is not normal: call your surgeon the same day so an ultrasound can check for a clot. Chest pain or sudden shortness of breath needs 911.

How long after foot surgery can a blood clot form?

Most clots form within the first six weeks, while you are least mobile, but the risk does not stop on a set date. In a 2024 study of 301,256 foot and ankle patients, about a third of clots were found in the first two weeks and nearly as many after six weeks, so keep moving your calf and watch for warning signs until you are back on your feet normally.

Still have a question about coverage or cost? Book online and we will check your benefits before your visit: Book in Howell · Book in Bloomfield Township. Prefer to talk it through first? Call (810) 206-1402.