Knee Replacement: Best Sitting Positions, What to Avoid, and Tips for Recovery

What is the best position to sit after knee replacement?

The optimal sitting position after knee replacement surgery prioritizes maintaining knee extension, minimizing prolonged deep flexion, and promoting circulation to reduce swelling and stiffness, ensuring proper recovery and long-term joint health.

Understanding Post-Operative Goals

Following a total knee replacement (TKR), the primary goals of rehabilitation are to reduce pain and swelling, restore range of motion (ROM), improve strength, and regain functional mobility. How you position your body, particularly your knee, plays a critical role in achieving these objectives and preventing complications such as flexion contracture (where the knee cannot fully straighten).

Key Principles for Post-Knee Replacement Sitting

When considering any sitting position, keep the following scientific principles in mind:

• Prioritize Knee Extension: The ability to fully straighten your knee (achieve 0 degrees of extension or even hyperextension, if your surgeon allows) is crucial for a natural gait and overall function. Prolonged sitting with the knee bent can lead to stiffness and a flexion contracture.
• Avoid Deep Flexion: Bending the knee beyond approximately 90 degrees for extended periods can place undue stress on the new joint, increase swelling, and contribute to discomfort. It also makes standing up more challenging.
• Elevate the Leg: Elevating your leg above heart level helps to reduce swelling, a common issue post-surgery, by promoting venous return. This is especially important in the initial weeks.
• Promote Circulation: Regular changes in position and gentle movement prevent blood pooling and reduce the risk of deep vein thrombosis (DVT).
• Maintain Spinal Alignment: While focusing on the knee, don't neglect your spine. Good posture minimizes compensatory pain in your back or hips.

Recommended Sitting Positions

The best sitting positions are those that support your knee's recovery goals:

• Sitting with Leg Elevated and Straight: This is often the most recommended position, especially in the early recovery phase.
  • Sit in a comfortable, firm chair.
  • Place your operated leg on an ottoman, another chair, or a stack of pillows, ensuring the knee is as straight as possible or with a very slight bend, but never dangling.
  • The heel should be supported, but the knee should have a slight gap beneath it if possible, allowing gravity to gently assist with extension.
  • Ensure your leg is elevated above the level of your heart to aid in swelling reduction.
• Sitting in a Recliner: A recliner allows you to adjust the angle of your torso and legs.
  • Choose a recliner that permits you to keep your knee relatively straight or with minimal flexion.
  • Avoid recliners that force your knees into a deeply bent position.
  • This position can be comfortable for short periods, especially if it allows for leg elevation.
• Sitting in a High-Backed, Firm Chair: For general sitting, choose a chair that provides good support.
  • Ensure the chair is high enough that your feet can be flat on the floor or a stable footrest, and your hips are slightly higher than your knees.
  • Avoid chairs that cause your knees to be significantly bent or lower than your hips.
  • Use a pillow for lumbar support if needed.

Positions to Avoid or Limit

Certain sitting positions can hinder recovery and should be avoided:

• Low, Deep Chairs or Couches: These require excessive knee flexion to sit down and stand up, putting strain on the new joint. They also make it difficult to achieve knee extension.
• Crossing Your Legs: This motion can twist the knee joint, impede circulation, and place uneven stress on the soft tissues surrounding the new joint.
• Prolonged Sitting with Legs Dangling: Allowing your leg to hang down for extended periods can increase swelling in the ankle and foot, and contribute to knee stiffness.
• Sitting on the Floor: This position typically requires extreme knee flexion and is highly discouraged in the early and intermediate stages of recovery.
• Sitting with a Pillow Directly Under the Knee: While elevation is good, placing a pillow directly under the knee can encourage a bent-knee position, making it harder to achieve full extension. Instead, support the ankle/heel to allow the knee to relax into extension.

Ergonomics and Support

Optimal sitting isn't just about the angle of your knee; it's also about your environment:

• Chair Firmness: Opt for firm chairs over soft, plush ones. A firm surface provides better support and makes it easier to get up.
• Armrests: Chairs with sturdy armrests are invaluable for assistance when standing up and sitting down, reducing strain on the operated leg.
• Footrests: If your chair is too high, use a stable footrest to ensure your feet are flat and your knees are not forced into an awkward angle.
• Pillows: Utilize pillows strategically for elevation (under the heel/ankle) and lumbar support.

Importance of Movement and Position Changes

No single sitting position is ideal for extended periods. Regular movement is paramount:

• Frequent Position Changes: Aim to change your position every 30-60 minutes.
• Short Sitting Durations: Limit continuous sitting to short intervals, especially in the early weeks.
• Gentle Exercises: Incorporate the gentle range-of-motion exercises prescribed by your physical therapist even while seated, such as ankle pumps or knee straightening exercises.
• Walk Breaks: Get up and walk for a few minutes whenever possible to promote circulation and prevent stiffness.

Listening to Your Body and Consulting Your Care Team

While these guidelines are evidence-based, individual recovery can vary.

• Pain is a Guide: If a position causes increased pain, throbbing, or swelling, adjust it immediately.
• Follow Professional Advice: Always adhere to the specific instructions provided by your orthopedic surgeon and physical therapist. They can provide personalized advice based on your unique surgical procedure, progress, and any specific considerations.

Conclusion

The "best" sitting position after knee replacement is not a static one, but rather a dynamic approach that prioritizes knee extension, avoids excessive flexion, manages swelling through elevation, and incorporates frequent movement. By understanding and applying these biomechanical principles, you can significantly contribute to a smoother recovery, improved functional outcomes, and the long-term success of your new knee joint.