How to Sleep After Knee Replacement: Positions, Pillows and Bed Setup
Quick answer: After a knee replacement, MedlinePlus, the NHS and the hospital guides we checked all repeat one rule: don't sleep or rest with a pillow under your knee. Keep the knee straight, and if you want support, put the pillow under your heel or ankle instead. AAOS says you can safely sleep on your back, on either side, or on your stomach, and several hospital guides suggest a pillow between your knees if you lie on your side. Trouble sleeping is common in the first weeks. Follow the instructions from your own surgeon and physical therapist.
This article covers knee replacement. If you or someone you care for had a hip replaced, see our guide on how to sleep after hip replacement, because the hip rules are different.
What is the best sleeping position after knee replacement?
The knee guides we checked don't set a fixed sleeping position. The American Academy of Orthopaedic Surgeons (AAOS) says, "You can safely sleep on your back, on either side, or on your stomach." (AAOS OrthoInfo) The NHS says you do not need to sleep in a special position after the operation, and University Hospital Southampton's guide says, "You can sleep in any position that you find comfortable." (NHS; University Hospital Southampton)
The position of the knee matters more. Five patient guides say:
| Source | What it says about sleeping and the knee |
|---|---|
| MedlinePlus (U.S. National Library of Medicine) | When lying in bed, keep a pillow under your heel or ankle, not your knee. Keep your knee straight. |
| NHS (UK) | Do not sleep with a pillow under your knee. No special sleeping position is needed. |
| Nova Scotia Health (Canada) | On your side, put a pillow between your knees. On your back, do not put a pillow under your operated knee. |
| Royal Wolverhampton NHS Trust (UK) | You may be more comfortable on your back or on your side with a pillow between your knees. Do not put a pillow underneath your knee. |
| Royal Devon University Healthcare NHS Trust (UK) | Do not sleep or rest with a pillow underneath your knee. |
(MedlinePlus; NHS; Nova Scotia Health; Royal Wolverhampton; Royal Devon)
Why you shouldn't put a pillow under your knee
The hospital guides explain why. Nova Scotia Health says a pillow under the operated knee "may cause your knee to heal in a bent position." Royal Wolverhampton says it "will restrict blood flow and cause stiffness in the joint, making it more difficult to move." Royal Devon says resting with a pillow under your knee "could lead to a stiff bent knee (and problems walking)." (Nova Scotia Health; Royal Wolverhampton; Royal Devon)
MedlinePlus says: "It is important to keep your knee straight." (MedlinePlus)
Can you sleep on your side after knee replacement?
Yes, according to AAOS and the hospital guides above, unless your surgeon tells you otherwise. Nova Scotia Health and Royal Wolverhampton suggest a pillow between your knees when you lie on your side, and University Hospital Southampton says a pillow between your legs may add comfort. (AAOS; Nova Scotia Health; Royal Wolverhampton; University Hospital Southampton)
Can you sleep in a recliner after knee replacement?
None of the guides we checked gives a rule for sleeping in a recliner after knee replacement, so ask your surgical team. Two points from the guides apply. First, the knee should not rest bent, as covered above. Second, Royal Devon says that if your legs are swollen, "elevating them on a foot stool or in a recliner chair isn't enough," and recommends lying flat on the bed with your legs raised on several pillows instead. (Royal Devon) MedlinePlus also says to try not to sit for more than 45 minutes at a time. (MedlinePlus)
How to raise your leg in bed for swelling
AAOS says you may have moderate to severe swelling in the first few days or weeks after surgery, and mild to moderate swelling for about 3 to 6 months. To reduce it, AAOS says to elevate your leg and apply ice, and that compression stockings may also help. (AAOS OrthoInfo) The hospital guides describe how to do the elevation in bed:
- Support the whole leg, not just the knee. Royal Devon says to make sure the pillows "are not just directly under your knee," and Nova Scotia Health says to place pillows under your leg, not just under your knee.
- Keep the knee as straight as you can. (Nova Scotia Health; Royal Devon)
- Royal Devon recommends lying flat on the bed with your legs elevated on several pillows for 30 minutes at least twice a day. University Hospital Southampton suggests resting on your bed for at least an hour every day with your feet on one pillow and your head flat on another.
(Royal Devon; Nova Scotia Health; University Hospital Southampton) Your own team may give different times, so use theirs.
Why is it hard to sleep after knee replacement?
Nova Scotia Health says, "You may have trouble sleeping for up to 12 weeks after your surgery. This is common." Royal Devon says disturbed sleep in the first few weeks after an operation is common and usually improves with time. (Nova Scotia Health; Royal Devon) If you can't manage the pain or it isn't getting better, Nova Scotia Health says to talk with your health care provider, physiotherapist or pharmacist.
How to set up your bed before surgery
- Check the height. MedlinePlus says your bed should be low enough for your feet to touch the floor when you sit on the edge. (MedlinePlus) Our guide to the best bed height for seniors shows how to measure.
- Sleep on the main floor if you can. MedlinePlus suggests setting up a bed or using a bedroom on the same floor, and AAOS says you may need to temporarily change rooms, for example making the living room your bedroom. (MedlinePlus; AAOS)
- Keep things within reach. AAOS suggests a "recovery center" with the items you use often within easy reach. (AAOS)
- Clear the floor. AAOS says to remove throw rugs or area rugs and to fasten electrical cords around the edges of the room. (AAOS) Our guide to why older adults fall out of bed covers more bedroom safety steps.
- Plan the bathroom trip. MedlinePlus suggests having a bathroom or a portable commode on the same floor where you spend most of your day. (MedlinePlus)
Warning signs at night
AAOS lists these warning signs of a blood clot: pain in your leg or calf unrelated to your incision, tenderness or redness above or below your knee, and increasing swelling of your calf, ankle, or foot. Signs that a clot has traveled to the lungs include shortness of breath, sudden onset of chest pain, and localized chest pain with coughing. AAOS says to tell your doctor right away if you develop any of these signs. (AAOS OrthoInfo)
If getting in and out of bed stays hard
Ask your physical therapist about bed height and equipment before you go home. Some families also look at beds that raise the person toward standing. Our guide to the best beds for seniors with mobility issues explains the types, and you can browse EzLift lift beds. A bed is not a treatment, and it doesn't replace your surgeon's or therapist's instructions.
FAQ
Can I put a pillow under my knee after knee replacement?
No, according to MedlinePlus, the NHS and the hospital guides we checked. Put the pillow under your heel or ankle so the knee stays straight. Guides warn that a pillow under the knee can lead to a stiff, bent knee.
Can I sleep on my side after knee replacement?
AAOS says you can safely sleep on your back, on either side, or on your stomach. Several hospital guides suggest a pillow between your knees when you lie on your side. Check with your surgeon if you were given different instructions.
How should I elevate my leg in bed after knee replacement?
Support the whole leg on pillows, not just the knee, and keep the knee as straight as you can. Royal Devon suggests lying flat with your legs on several pillows for 30 minutes at least twice a day.
How long does trouble sleeping last after knee replacement?
Nova Scotia Health says you may have trouble sleeping for up to 12 weeks after surgery and that this is common. Talk to your care team if you can't manage the pain.
Sources
- American Academy of Orthopaedic Surgeons, OrthoInfo, "Activities After Total Knee Replacement": https://orthoinfo.aaos.org/en/recovery/activities-after-knee-replacement/
- MedlinePlus, "Knee joint replacement - discharge" (review date 11/7/2024): https://medlineplus.gov/ency/patientinstructions/000170.htm
- NHS, "Recovering from a knee replacement": https://www.nhs.uk/tests-and-treatments/knee-replacement/recovery/
- Nova Scotia Health, "After Knee Replacement Surgery: 1 to 12 Weeks": https://www.nshealth.ca/sites/default/files/documents/2459-2024.12.24.pdf
- The Royal Wolverhampton NHS Trust, "Exercise and guidance following Knee Replacement": https://royalwolverhampton.nhs.uk/wp-content/uploads/2025/09/Exercise_and_guidance_following_Knee_Replacement.pdf
- Royal Devon University Healthcare NHS Foundation Trust, "Preparing for your knee replacement operation at the PEOC - A patients guide" (June 2025): https://www.royaldevon.nhs.uk/media/hbabt2kd/preparing-for-your-knee-replacement-operation-at-the-peoc-a-patients-guide-rd-e-20-084-002.pdf
- University Hospital Southampton NHS Foundation Trust, "Total knee replacement" patient information: https://www.uhs.nhs.uk/Media/UHS-website-2019/Patientinformation/Muscles,jointsandbones/Total-knee-replacement-HHFT-4037-PIL.pdf
Written by the EzLift Team, EzLift's organizational authorship team. Last reviewed November 4, 2026. This guide summarizes published patient instructions; it is not medical advice. Your surgeon's and therapist's instructions come first, because advice differs by surgery and by person.