Procedure prep
Fasting Before Knee Replacement
Knee replacement is major surgery under general or spinal anesthesia. Fasting is standard, and medication planning is especially important.
Medically reviewed by
Dr. Saurabh Shukla, MBBS, DNB Anesthesiology
· Last updated June 2026
Fasting for this procedure
Stop solid food and milk about 8 hours before, a light meal about 6 hours before, and clear liquids about 2 hours before your hospital arrival time.
→ Get your exact fasting times with the calculator
Medicines to check
- Blood thinners (aspirin, clopidogrel, warfarin, Eliquis, Xarelto) — see medications to stop.
- Diabetes medicines & insulin — they need a plan. See diabetes tablets.
- GLP-1 (Ozempic, Wegovy, Mounjaro) — tell your team. See the GLP-1 guide.
- Blood pressure medicines — confirm which to take with a sip of water and which to hold.
- Anti-inflammatory painkillers and supplements that thin the blood are often stopped beforehand — confirm the list.
When this surgery may be delayed
- Fever, a new cough/cold, or a chest infection
- Vomiting or diarrhea
- Very high blood pressure or blood sugar
- You ate or drank outside your fasting window
- A skin infection, wound, or ulcer near the knee
- A dental, urine, or chest infection (raises joint-infection risk)
Reports & documents to carry
- Photo ID and insurance card
- A written list of all your medicines and doses
- Any blood tests, ECG, or scans your team asked for
- Consent forms or referral letters, and allergy details
- Knee X-rays / scans
- Pre-op clearance or 'fitness for surgery' if requested
What to ask your anesthesia team
- Will I have general anesthesia, spinal/regional, or sedation?
- Which medicines do I take or hold on the morning of surgery?
- When can I eat and drink afterward?
- Will I go home the same day, and who can drive me?
Your prep checklist
Tick things off as you sort them — saved on this device only, nothing is sent anywhere.
A general guide — your hospital's own instructions always come first.
Frequently asked questions
How long do I fast before a knee replacement?
Usually solids stop about 8 hours before and clear liquids about 2 hours before your hospital arrival time. Your team will also give you a detailed medication plan.
Why might my knee replacement be postponed?
Any active infection — skin near the knee, dental, urine, or chest — can postpone a joint replacement, because infection can spread to the new joint. Tell your team about any infection early.