Why You Should Avoid Putting a Pillow Under Your Knee After a Knee Injury: The Science Behind Early Mobility for Faster Recovery

Posted on: April 1st, 2025 by Our Team

After knee surgery or injury, it’s common for patients to rest with a pillow under the knee for comfort. However, this seemingly harmless habit can actually hinder your recovery by limiting knee extension (straightening your knee) and promoting stiffness. In this blog, we’ll explore why this positioning is detrimental and why early mobility is essential for a quicker, more complete recovery.

1. Knee Extension and Its Importance in Recovery

Knee extension—the ability to fully straighten the knee—is essential for mobility after an injury. When the knee can’t fully straighten, it can lead to difficulties with walking, climbing stairs, and other daily activities.

• Loss of Extension: Keeping the knee bent for extended periods (such as by propping it up with a pillow) can lead to stiffness and the formation of scar tissue, which makes it harder to regain full extension.
• Scar Tissue and Adhesions: Inadequate movement can encourage the development of scar tissue and adhesions inside the joint, restricting movement and delaying recovery.

2. How Propping the Knee with a Pillow Can Slow Recovery

While elevating the knee might feel comfortable, placing a pillow directly under the knee encourages flexion and limits knee extension, which is critical for recovery.

• Promotes Flexion: By keeping the knee bent, you’re reinforcing the flexed position, making it harder to straighten the knee and increasing the risk of long-term stiffness.
• Lack of Early Movement: Early mobility is key to restoring full range of motion. Without regular movement, muscles and ligaments around the knee may become stiff, and scar tissue can form, which impedes progress.

3. The Science Behind Early Mobility

Research supports that early movement is essential for optimal healing. Here’s how it benefits the knee:

• Synovial Fluid and Lubrication: Movement encourages the circulation of synovial fluid, which lubricates the knee joint and nourishes cartilage, helping to prevent stiffness.
• Preventing Muscle Atrophy: Early, controlled movement prevents muscle weakening (atrophy), which is crucial for knee support during recovery.
• Reducing Scar Tissue Formation: Moving the knee early on can help break up scar tissue before it limits mobility, ensuring a quicker recovery.

4. Proper Elevation and Resting Position

To properly elevate the knee without compromising mobility:

• Elevate the Heel: Use pillows or towels stacked under the heel, not under the knee, to keep the knee in a neutral position while reducing swelling. This encourages extension and avoids promoting a flexed posture.
• Avoid Pillows Under the Knee: Never place a pillow directly under the knee, as it forces the joint into a bent position and hinders the natural extension process.

5. Early Mobility: The Key to a Faster Recovery

Instead of immobilizing the knee with a pillow under it, prioritize early, gentle mobility. This approach helps prevent stiffness, reduces the risk of complications, and accelerates your recovery by promoting natural knee movement.

Propping your knee up with a pillow may seem like a good way to rest, but it can actually slow down your recovery. Elevate your knee properly with pillows or towels under the heel to maintain a neutral position, encourage extension, and support early mobility. By doing so, you’ll improve flexibility, prevent scar tissue build-up, and speed up your return to normal function.