Home / Wedge and knee pillows

Knee replacement pillow: support the ankle, keep the knee straight

By the Life in Good Form editors. Updated 2026-10-12.

We research products from makers' specs and health sources; we do not run hands-on tests. Links to Amazon may earn us a commission at no cost to you. How this works.

Quick answerAfter a total knee replacement, keep the operated knee straight when resting on your back rather than propping it on a pillow. Robert Jones and Agnes Hunt Orthopaedic Hospital warns that a pillow under the knee can lead to tight tissues and a fixed bend. It suggests raising the foot end of the mattress for swelling. A straight leg elevation support and a small heel roll for prescribed exercises serve different purposes from a bent knee bolster. Your surgeon's positioning instructions come first.
Our picks at a glance

Compare the picks and what to watch out for

Why no pillow under the knee after surgery

It feels natural to rest a sore, swollen knee over a pillow. The problem is that it keeps the knee bent. Robert Jones and Agnes Hunt Orthopaedic Hospital says to keep the operated knee straight when resting on your back and warns that a pillow beneath it can tighten the tissues behind the knee.

OrthoInfo's exercise guide from the American Academy of Orthopaedic Surgeons describes a similar aim. One exercise places a small rolled-up towel just above the heel so the heel is not touching the bed, then asks you to fully straighten the knee and touch the back of it to the bed. A pillow under the knee works against that.

Elevating the leg the right way

Swelling is common after surgery. OrthoInfo says you can relieve it by elevating your leg and applying an ice pack or ice wrapped in a towel. Robert Jones and Agnes Hunt Orthopaedic Hospital recommends raising the feet above heart level by placing pillows, a blanket or a duvet under the foot end of the mattress. It describes using this setup for rest on the bed in the day and at night. Ask your own team how to adapt that arrangement to your bed or a separate leg support.

SetupHelps withNote
Lying down, leg on a firm elevation wedge or pillows under the calf and ankleSwellingFoot above the heart; nothing behind the knee
Lying down, small roll above the heelStraightening exercisesBack of the knee should be free to drop
Chair with footstoolRest during the dayOrthoInfo suggests a footstool for intermittent elevation; it helps comfort more than swelling

What to look for in a post-surgery leg wedge

For general leg elevation products, see our leg wedge pillow guide.

Setting up home before surgery

  1. Pick where you will lie down for elevation breaks and put the wedge or pillows there.
  2. Keep a folded towel or small bolster for heel-prop exercises.
  3. Have a chair with a footstool, as OrthoInfo suggests for early recovery.
  4. Prepare ice packs. OrthoInfo recommends ice wrapped in a towel for swelling, alongside leg elevation.
  5. If your surgeon prescribes support stockings or compression boots to reduce clot risk and swelling, as OrthoInfo describes, keep them handy.

Warning signs to report right away

OrthoInfo lists signs of a possible blood clot in the leg: increasing calf pain, tenderness or redness above or below the knee, and new or increasing swelling in the calf, ankle and foot. Sudden shortness of breath or sudden chest pain can signal a clot in the lung and needs emergency care. Signs of infection include a persistent fever higher than 100 F, increasing redness, tenderness or swelling of the wound, and drainage from the wound.

What to look for when you buy

Firm straight-top leg elevation wedge

Best for: Lying-down elevation breaks after knee replacement

Provides a straight support for elevation breaks. Ask your team how high to raise it and whether it suits the position they prescribed.

Watch out: Avoid models with a built-in knee bend unless your surgeon approves.

See options on Amazon

Small heel or ankle bolster

Best for: Knee straightening exercises

OrthoInfo's exercise guide uses a small roll just above the heel so the knee can straighten fully toward the bed.

Watch out: Use it for exercise time as instructed, not as an all-night knee support.

See options on Amazon

Reusable cold pack wrap for the knee

Best for: Swelling and soreness in the first weeks

OrthoInfo describes ice and leg elevation as ways to relieve swelling after surgery.

Watch out: Keep a cloth between pack and skin, and keep it dry over the incision.

See options on Amazon

Footstool or leg rest for a chair

Best for: Comfortable daytime sitting

OrthoInfo suggests a footstool for intermittent leg elevation in early recovery.

Watch out: For swelling, the hospital describes bed rest with the feet above heart level; a chair footstool may not provide that height.

See options on Amazon
When to talk to a doctor: Follow your own surgeon's positioning and elevation instructions over any general advice. Call your doctor right away for increasing calf pain, new swelling, a fever over 100 F, or wound redness or drainage, and call 911 for sudden shortness of breath or chest pain.

Questions people ask

Why can't you put a pillow under your knee after knee replacement?
It keeps the knee bent, while recovery focuses on full straightening. The hospital warns that propping the knee this way can tighten the tissues behind it.
How long should I avoid a pillow under my knee?
Follow the timeline from your surgeon or physical therapist. The hospital advises keeping the knee straight when resting on your back; it does not give a single stop date for this precaution.
How should I elevate my leg after knee replacement?
Lie down with the leg on pillows or a firm wedge under the calf and ankle so your foot is above your heart.
Can I use a knee wedge pillow after surgery?
Not one that bends the knee, unless your surgeon or physical therapist says it is fine. A straight leg elevation wedge is the safer choice to ask about.

Sources

Sources checked 2026-10-12.

Related guides