Calf pain after knee arthroscopy is usually from muscle soreness, a changed walking pattern, or pressure from the tourniquet used during surgery. But it can be a blood clot (deep vein thrombosis, DVT), which is uncommon but must be ruled out – especially if one calf is swollen, warm or red. A simple ultrasound scan gives the answer.
Go to the emergency department or call 108 now if you have
- Sudden breathlessness, chest pain, a racing heart or coughing blood
- Possible clot in the lung
- A pale, cold or very numb foot
- Severe, rapidly worsening calf pain with a tight, swollen calf
Call your surgeon the same day if you have
- One calf more swollen than the other
- Warmth, redness or tenderness in the calf
- Calf pain that is getting worse rather than better after the first few days
This guide from the knee team at Sports Orthopedics Institute, Bengaluru explains the causes, how to tell them apart, and what to do.
Causes at a Glance
|
Cause |
How common |
Typical features |
Urgency |
|---|---|---|---|
|
Muscle soreness and altered walking |
Very common |
Dull ache, often both calves; eases with gentle movement; no swelling |
Normal |
|
Tourniquet effect |
Common |
Ache, cramp or tingling starting within 1–2 days; gradually improves |
Monitor |
|
Deep vein thrombosis (DVT) |
Uncommon |
One-sided calf pain with swelling, warmth or redness; worsening over days |
Same day |
|
Baker's cyst leak |
Uncommon |
Sudden calf pain and swelling; bruising may spread towards the ankle |
Same day – can mimic DVT |
|
Nerve irritation |
Uncommon |
Burning, tingling or numbness; doesn't follow a muscle pattern |
Routine review |
|
Pulmonary embolism |
Rare |
Breathlessness, chest pain, fast heart rate |
Emergency |
|
Compartment syndrome |
Very rare |
Severe, escalating pain; tight, shiny calf; numb or weak foot |
Emergency |
Deep Vein Thrombosis (DVT): The Cause to Rule Out
A DVT is a blood clot in a deep vein of the leg. After knee arthroscopy, a clot that causes symptoms is uncommon, but it matters because a clot can travel to the lungs.
How common is it?
Figures vary widely depending on whether studies count only clots that cause symptoms or also tiny clots found by routine scanning. In the large Dutch POT-KAST trial of 1,451 patients, a symptomatic clot within three months occurred in 0.4% of those who received no blood thinner (NEJM, 2017). Rates are higher in people with risk factors.
Who is at higher risk?
- Previous DVT or pulmonary embolism, or a family history of clotting disorders
- Age over 40
- Diabetes
- Smoking
- Longer operations or tourniquet times (often quoted as over 60 minutes)
- Obesity, cancer, the contraceptive pill or hormone therapy
- Prolonged immobility after surgery
In a study of patients over 40 having knee arthroscopy, previous DVT, diabetes and smoking significantly increased the risk (Özcan et al., 2019).
Symptoms
- Pain or tenderness in one calf, often worse on walking or standing
- Swelling of one calf or ankle compared with the other
- Warmth, redness or discolouration
- Most clots appear within the first two weeks, but they can develop later
Some DVTs cause few symptoms, and pain when the foot is pulled upwards (Homan's sign) is unreliable – which is why an ultrasound scan is needed if there is any doubt.
Other Causes of Calf Pain
Muscle soreness and altered walking
After surgery you walk differently to protect the knee, which overworks the calf muscles. Expect a dull, diffuse ache, often in both calves, that is worse at the end of the day or after physiotherapy and improves with gentle movement. There is no swelling, warmth or redness.
Tourniquet effect
A tourniquet around the thigh keeps the knee free of blood during surgery. It can temporarily affect the muscles and nerves below it, causing an ache, cramps or tingling in the calf or foot from the first day or two. This usually settles over days to a few weeks.
Baker's cyst leak
If you had a fluid-filled cyst behind the knee, it can leak or burst, and the fluid tracks into the calf. This causes sudden pain and swelling and can look exactly like a DVT; bruising may spread down towards the ankle. An ultrasound tells them apart.
Nerve irritation
Nerves around the back and sides of the knee can be irritated, causing burning, tingling or patches of numbness. Most settle with time; persistent symptoms beyond about 6 weeks may need nerve tests.
Compartment syndrome (very rare)
Pressure builds inside the calf muscle compartment and cuts off blood supply. Warning signs are severe pain out of proportion to the surgery, pain on gently moving the toes or ankle, a tight shiny calf, and numbness or weakness in the foot. This is an emergency needing surgery within hours.
How Calf Pain Is Diagnosed
- Examination: your doctor checks for swelling, warmth, tenderness and compares both calves.
- Doppler (duplex) ultrasound: the main test for DVT – quick, painless and radiation-free. It also shows a Baker's cyst.
- D-dimer blood test: a normal result helps rule out a clot in low-risk patients, but it is often raised after any surgery, so a high result alone doesn't mean you have a DVT.
- CT scan of the chest: if a clot in the lung is suspected.
- MRI or nerve tests: for unclear or persistent symptoms.
Treatment by Cause
|
Cause |
Treatment |
|---|---|
|
DVT |
Blood-thinning medicine, usually for about 3 months; keep walking as advised; compression stockings for comfort if recommended |
|
Pulmonary embolism |
Emergency hospital treatment with blood thinners |
|
Muscle soreness |
Gentle walking, ankle pumps, calf stretches, physiotherapy, short-term painkillers |
|
Tourniquet or nerve irritation |
Usually settles on its own; monitored by your surgeon |
|
Baker's cyst leak |
Rest, elevation and treatment of the underlying knee problem |
|
Compartment syndrome |
Emergency operation (fasciotomy) to release the pressure |
What's Normal, Week by Week
|
Time after surgery |
Usually normal |
Report it |
|---|---|---|
|
Days 1–3 |
Mild calf ache or tingling; knee swelling |
Severe one-sided calf pain; a pale, cold or very numb foot |
|
Days 4–14 |
Calf stiffness, morning soreness, improving knee |
Calf swelling, warmth or redness; worsening pain; fever above 38.5°C |
|
Weeks 2–6 |
Occasional ache after physio that settles within a day |
Pain not improving; new calf swelling; breathlessness |
|
After 6 weeks |
Calf comfortable with normal walking |
Any new calf pain or swelling |
Preventing Blood Clots After Knee Arthroscopy
What you can do
- Walk early and often – short walks around the house from the first day, as your surgeon allows
- Ankle pumps – point and pull your foot up and down regularly when sitting or lying
- Avoid long periods sitting still, including long car journeys and flights in the first weeks
- Drink enough fluids and limit alcohol
- Wear compression stockings if they are recommended for you
- Take any prescribed blood thinners exactly as directed
Do I need a blood-thinning injection?
Not routinely. In the POT-KAST randomised trial, eight days of low-molecular-weight heparin injections after knee arthroscopy did not reduce symptomatic clots compared with no injections (0.7% vs 0.4%) (NEJM, 2017). A 2024 systematic review concluded that for high-risk patients, injections or tablet blood thinners are appropriate (Knee Surg Relat Res, 2024).
Your surgeon will assess your personal risk – for example, previous clots, age, diabetes, smoking and longer procedures such as ACL reconstruction or meniscus repair – and decide whether you need medication.
How Sports Orthopedics Institute Can Help
We assess every patient's clot risk before knee surgery and offer urgent review, including Doppler ultrasound, if calf pain develops afterwards. Our team in HSR Layout, Bengaluru also provides structured rehabilitation after arthroscopy, ACL reconstruction and meniscus surgery.
Worried about calf pain after knee surgery? Call +91 6364538660 or +91 9008520831, or book online at sportsorthopedics.in. If you have breathlessness or chest pain, call 108 or go to the nearest emergency department first.
Frequently Asked Questions
Is calf pain normal after knee arthroscopy?
A mild ache in the first days is common, from muscle soreness, changed walking and the tourniquet. Calf pain that is severe, one-sided, worsening, or comes with swelling, warmth or redness is not normal and needs checking the same day.
How do I know if it's a blood clot or just a sore muscle?
Muscle soreness is usually a dull ache, often in both legs, that eases with movement and has no swelling. A clot is more often in one calf, gets worse over days, and comes with swelling, warmth or redness. Only an ultrasound can say for sure.
How soon after surgery can a clot form?
Most occur in the first two weeks, but they can appear later, especially in people with risk factors.
How common are blood clots after knee arthroscopy?
Symptomatic clots are uncommon – about 0.4% of patients without blood thinners in a large Dutch trial – but more likely with risk factors such as previous clots, diabetes or smoking.
Will I be given a blood thinner?
Only if your risk is high. A large trial found routine injections didn't reduce clots after knee arthroscopy, so most patients don't need them.
My ultrasound was normal but my calf still hurts. What now?
A normal scan is reassuring. Persistent pain is more likely to be muscular, tourniquet-related or from nerve irritation. Keep walking and doing your exercises, and see your surgeon if it isn't improving within a few weeks.
Can physiotherapy cause calf pain?
Yes, temporary soreness after a session is normal and should ease within a day. Report pain that keeps getting worse or comes with swelling.
References
- van Adrichem RA, et al. Thromboprophylaxis after knee arthroscopy and lower-leg casting (POT-KAST and POT-CAST). New England Journal of Medicine, 2017;376:515–525.
- Özcan M, Erem M, Turan FN. Symptomatic deep vein thrombosis following elective knee arthroscopy over the age of 40. Clinical and Applied Thrombosis/Hemostasis, 2019.
- Dave U, et al. Deep vein thrombosis prophylaxis in patients who undergo knee arthroscopy: a systematic review. Knee Surgery & Related Research, 2024.
- Mayo Clinic. Deep vein thrombosis: symptoms and causes.
- AAOS OrthoInfo. Deep vein thrombosis.
Medical disclaimer: This article is for general information only and does not replace advice from your doctor. If you have chest pain or breathlessness, seek emergency care immediately.