improving knee flexion after surgery the prehab guys

How To Improve Knee Flexion After Surgery

After surgery, understanding how to improve knee flexion is absolutely critical. While we’ve discussed the importance of regaining knee extension extensively, restoring knee flexion is a close runner up for your rehab goals after surgery. Restoring knee flexion is often not comfortable (as can be for any motion after surgery!), but with dedication and consistent time spent working on your mobility, we are confident you can get there! In this article, we’re going to cover some of our favorite exercises to improve knee flexion after surgery!


Why is Improving Knee Flexion After Surgery Important?

Now first things first – please listen to your orthopedic surgeons’ range of motion guidelines! Not every knee surgery is the same, as there may be different precautions you must follow after a meniscus repair vs. an isolated ACL reconstruction. After some surgeries, you may want to push the range of motion to what is tolerable, whereas in others, pushing the range of motion past a certain degree may actually be harmful! So again – please listen to your physical therapist and orthopedic surgeon for guidelines on how to improve your knee flexion depending on your exercise parameters!

When it comes to starting to move so that you can actually improve knee flexion after surgery, it may not be all that comfortable.

Much of the lack of knee flexion immediately after surgery is not only due to pain, but also knee swelling or edema in response to the surgery. Inside of your knee is a joint capsule that surrounds the entire joint, imagine this joint capsule is shaped like a balloon. When there is increased swelling in the joint, the balloon gets bigger. It gets a lot harder to bend the knee with a bigger balloon inside of it! Thus, it’s important very early on to follow the P.O.L.I.C.E. principle of protection, optimal loading, icing, compression, and elevation to minimize as much swelling as possible as that will only limit our knee flexion gains after surgery!

READ: THE TRUTH ABOUT ICING The truth about icing knee flexion post op the prehab guys


Knee Flexion Exercise Volume Is Key

As our bodies are healing from surgery, our tissues are undergoing many changes. YOU are your body’s best healer! Early mobility has not only been deemed appropriate after surgery, but also necessary in order to facilitate a healthy healing response. An article by Kaye et al discusses the positive outcomes related to early mobility after surgery, some of which include decreased hospital length of stay, improved patient satisfaction, and decreased postoperative complications! Later on, in the middle and late tissue healing phases specifically, we want to gently apply forces to the tissues inside of the knee to increase range of motion. This will assist in tissue remodeling and the long-term success of tissue healing. A great overview of tissue healing phases from start to finish is well explained in a blog post we have recently written!

READ: WHAT YOU NEED TO KNOW ABOUT TISSUE HEALINGTissue Healing timelines knee flexion after surgery the prehab guys

The key to improve knee flexion after surgery is gently pushing into that uncomfortable range and trying to progressively increase the amount of time you spend there with each successive day.

What may feel tight and uncomfortable today should hopefully feel less restrictive tomorrow! But as any good physical therapist will tell you – each day is a new day. You should expect that some days are going to feel tighter than others, sometimes for no apparent reason! But many times, certain parts of the body may feel tighter because you did “too much too soon” the previous day or earlier in the day and the knee is more swollen.

Remember – minimizing swelling after surgery is goal number one! If you find that your knee is more swollen after your knee flexion exercises, it means you are doing too much! Scale back the intensity of the stretches, how much you are doing, or both until you find the amount of mobility work that your knee can handle at this time. The amount it can handle, like the tightness you feel each day, will change in time!


Knee Flexion After Surgery Exercises

The following exercises are some of our favorites to improve knee flexion after surgery! You will most likely find that one or a few of these exercises “feels best” for you, which is expected! Your knee is unique! Your surgery, injury, the current range of motion, pain levels, and so much more will dictate which of these exercises feels the most comfortable and effective for your knee.

How To Improve Knee Flexion

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Seated Knee Flexion Exercise After Knee Surgery – PROM, Other Leg Assist

Sample [P]Rehab Exercise Library Video

  • HOW: Sit at the edge of a table or some sort of elevated surface. Ideally, you don’t want your feet to touch the ground. Place your unaffected leg under your affected leg, fully supporting it. Slowly let your affected knee bend by lowering your feet. At some point, you will feel a gentle stretch. Hold for the desired amount of time, and then use your unaffected side to help straighten your knee out once again. Repeat.


  • FEEL: If you are doing this after surgery, it is normal for this to feel a bit uncomfortable. There should never be any sharp pain, but aching is fine.


  • COMPENSATION: Relax! Use your other leg to support your affected side.


Knee Flexion On Wall Exercise After Knee Surgery – PROM

  • HOW: Lie on your back close to a wall. Place your affected leg on the wall. Make sure your heel can slide on the wall, so wear a sock or place a pillow cloth or something else slippery around your foot so that it can slide. Slowly let gravity slide your leg down. As your leg slides down, your knee will bend more, which is the goal of this exercise. Bend as far as you can, hold that stretch for a few seconds, then return back to the starting position. Repeat.


  • FEEL: You should feel a slightly uncomfortable stretch at the end of your range. This is common and the goal of this exercise is to feel that little bit of discomfort so don’t be alarmed.


  • COMPENSATION: Let gravity bring your foot down as it slides against the wall, don’t try to move it yourself. Go slow!


Seated Knee Flexion Exercise After Knee Surgery – AAROM With A Strap

  • HOW: Begin in a seated position with a strap or a towel wrapped around the middle of your foot. Pull your foot in towards your butt. You may need to choke up on the strap to get leverage with your arms. When you get to the end of your motion, you have the option of holding or moving back and forth. You also have the option of laying on your back when performing this exercise.


  • FEEL: The closer your heel gets towards your butt the more stretch you will feel in your knee.


  • COMPENSATION: Avoid pulling in with your leg, keep the leg relaxed. The motion should be coming from your arms pulling your leg in.


Body On Knee Flexion Exercise After Knee Surgery PROM

  • HOW: Sitting on a bed or couch, remove your knee immobilizer. Put your heel on the ground with your knee unsupported. Using your arms and non-surgical leg, scoot your bottom forward with your surgical knee moving forward over your foot, moving into knee flexion. Use your arms and your non-surgical leg to return to starting position.


  • FEEL: You should feel a stretching sensation both around the front of your knee and even behind your knee. This should only be a mild discomfort, and not too much pain! As you continue to relax into a new, available range of motion, you can continue to move your body forward.


  • COMPENSATION: Avoid leaning your hip away towards the opposite leg. Keep your hips square and even without shifting your weight away.


Knee Flexion Mobility Closing Thoughts

Gaining mobility – flexion or extension – after surgery is one of the most important goals. Knee flexion, in particular, takes longer (that is expected) but with dedicated time working on it, we trust that you will get it back in no time! As always, listen to your orthopedic surgeon and physical therapist for guidance, but we are here to help when needed!

Looking For Knee [P]Rehab?knee flexion after surgery knee program the prehab guys

The Knee [P]Rehab Program is a 12-week, 3-phase program designed to rebuild your knees from the ground up. Whether you’re a weekend warrior, competitive athlete, superhero parent, or just someone interested in improving their knee health, you can 100% benefit from this program. We make it easy and teach you how to self [P]Rehab your knees and keep them healthy for anything life throws at you through detailed exercise programming and our signature education resource videos.


Don’t Forget About Knee Extension After Surgery!!



  1. Kaye AD, Urman RD, Cornett EM, et al. Enhanced recovery pathways in orthopedic surgery. Journal of Anaesthesiology Clinical Pharmacology . 35(1). doi:10.4103/joacp.JOACP_35_18.


Disclaimer – The content here is designed for information & education purposes only and is not intended for medical advice.

  • Bishal lakra
    Posted at 07:14h, 04 January Reply

    I can bend my knee because my patella frature into 2 piece but it joints now

  • Marla Washburn
    Posted at 04:37h, 02 February Reply

    Wish I would have seen this weeks ago! Now I have a question. I am 14 weeks post op left knee replacement. I have decided that I had a less than stellar physical therapy experience for 6 weeks following my 3 week in home therapy. Is it too late for me to do these flexion exercises you have shown here to gain more flexion or is the 120° I have all I’m going to get? (I will know today for sure what my flexion actually is…I had to quarantine for 4 weeks due to Covid so have just been doing the exercises at home that PT had me doing on site. I don’t feel like they pushed me to get a better bend, I feel like they were basically a sitter to make sure I did their list of movements. I didn’t ever feel challenged with them. I’m also having my right knee replaced soon. The surgery will be scheduled tomorrow as I see the surgeon after my final PT evaluation. One more question. Is it normal for me to still have pain when forcing the bend past what is comfortable? Does that mean that if I continue to push, the bend will increase over time?
    Is it common to still feel like I have swelling at this point? Questions for my doctor. Haha. I know! Will be talking to him tomorrow.

  • Michael Lau
    Posted at 10:07h, 03 February Reply

    Hey Marla!!!

    Sorry to hear about your less than stellar PT experience. We unfortunately cannot give you specific medical advice as we are not legally allowed to…

    Our best recommendation would be to swtich and find another PT who is able to push you a bit more, or potentially continue to read blogs like our and follow them at your own discretion.

    Everyone gets a differnt amount of flexion after a TKA – it is never too late to work on it IMO!

    You have great questions and they are more appropriate for your doctor of in person PT!

  • Ml
    Posted at 22:12h, 11 April Reply

    Hey,my femur bone fracture 6 months ago,till now can’t able to bend knee more than 40 degrees.i took 29 PT visits.still can’t able to bend my knee.iwhat kind of exercises do I need to do.

    • Sherif Elnaggar
      Posted at 05:03h, 12 April Reply

      Hello! Thank you for your question. Unfortunately we are unable to give direct medical advice on this platform as it is illegal. Continue to stay consistent with your exercises and consult with your physical therapist in person who can best evaluate how you can best improve your mobility. Consistency is your best friend!! Best of luck to you!!!

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