A main concern for any of us working with post-op TKA is lack of ROM, especially knee extension.  We know the patient should obtain full extension as soon as possible for proper gait & arthrokinematics of the tibiofemoral joint.  Not only for short term for long term control to help prevent hip and back problems in the future.

The debate may go on forever on the other factors that will affect this: vitality of the knee from the length and amount of contracture before surgery, how early rehab is implemented post-op, the type of intervention and just overall patient’s general activity level and adherence to therapy.  Hindsight is 20-20, lets look into the solution…or lack of an adequate solution.

Contracture is defined as the shortening of connective tissue.  Lack of knee extension can be tightening of biceps femoris, ligaments and mostly the posterior capsule. This does not respond to pounding on the joint with our body weight, but to daily low-load, long-duration stretch and in my opinion, consistent knee extension moment maneuvers.  The key here is daily and not aggressive pounding of the joint.

We have many avenues to address this but one that I just do not like is when the therapist uses excessive force mobilizing the knee into extension.  I have seen general A/P gliding as if the therapist wanted to break it the prosthesis to literally sitting on the knee.  Is this really needed?  Wouldn’t you think guarding, rebounding and just plain ol’ patient resistance would make this ineffective?  If you see a 2 degree change afterwards in the clinic, is this really functional and what is the carry-over?I’m not sure if being so aggressive makes us feel authoritative, powerful or just want to make a statement.  Needless to say, it is ridiculous.  We don’t do this with other surgeries, why the knee?

My solution?  Well, I don’t do what is described above. I feel graded grade 2-3 mobilizations in both anterior/posterior and posterior/anterior (more pain relieving) is very effective.  Even IR of tibia on femur is very responsive.  Most surgeons don’t address the mechanical fault, just take out arthritic joint.  See past post on this topic. Theoretically, am I taking the joint into the “end-range” with grade 2-3? No, but does it have to be? Would the patient respond better to pain-relieving manual therapy (even at late stages in post-op) than painful, not-looking-forward-to-any-physical-therapy-again approach?

My Top 5 Approaches:

1.  Mobilizations per description above and picture below.  NOT brutality and war with the knee.

2.  Knee Extension Moment Exercises.  See pictures below for a few examples.

3.  Low-load, long-duration stretch. Weight on knee with moist heat seated seems to be more effective than prone knee extension hanging from plinth.  We know what this looks like.

4.  Dynamic splinting.  A good case report here. Main reason this is not picked earlier is because I have not seen it personally.

5.  NOT sitting on knee.

What is your approach to this condition?  Is myofascial releases your agenda? Have you been exposed to dynamic splinting and if so, is it effective?  What products do you use?


  1. I have thought about this and I don’t have a consistent method when addressing lack of passive knee extension after a joint replacement. The most difficult situations in my area are when home health services were involved OR if the patient acquired a staph infection. In my local area, the quality of care provided during home health services is poor – the person would be better just coming to me in outpatient and foregoing home health services.

    To me, there doesn’t seem to be any restrictions in the joint when doing the mobilization as in the bottom photograph. Most of the knees generally have the feel of a lax knee joint (think ACL tear kind of a feeling). So, I don’t necessarily believe a joint that feels somewhat lax or really moves with the mobilization has joint proper stiffness. Yes, it is a nice technique to reduce discomfort but I don’t believe it is a worthwhile intervention for improving lack of extension.

    One thing I have noticed is how consistently the patient does the home program at home. To obtain full knee extension they can very easily just sit in a chair (even a recliner) and prop the ankle/foot up on a pillow or towel roll to provide a gravity-assisted gentle, long duration stretch. I’ve seen better results when patients do focus on moving/stretching the knee pretty much right after surgery and perform their home exercise programs a good 8-10 times a day (about 10 minutes or so each time). Those folks kick butt in their rehab and progress quite quickly. Granted, in those cases, they did come to me after surgery and they were educated and provided realistic expectations and rationale for why this is important for them to do.

    Sometimes the joint itself is swollen and that really does inhibit the ability to gain normalize motion. The sooner the edema is controlled the sooner the motion improves.

    Now, I will admit, I am a sneaky physical therapist. There is nothing more motivating for a patient than to be told if the patient obtains XX amount of improvement I won’t need to do Y. (Y being the not so pleasant lean percentage of my body weight through their joint technique.) I know it hurts a lot doing that kind of intervention, but at the same time I offer a better solution – THEY do the longer duration, low-load stretch and they won’t have me doing the thing that hurts because they will be making gains. 🙂 Seems to generally work pretty good.

    In the clinic, I can lock them into a position on a piece of equipment to provide a low-load, long duration stretch while I provide a joint distraction force. Often times I need to do something like that if the patient was *lucky* and acquired a staph infection. Their joints are very, very stiff and fibrosed.

    The other aspect you didn’t mention – the patella. In order for the patient to adequately contract the quad muscles to actively improve extension, the patella does need to slide/glide/move. Some attention should also be given to the patellar region to help with more quickly acquiring extension.

    It’ll be interesting to hear the thoughts of others.


  2. I do a variety of techniques for this population, including using appropriate TERT (total end range time) stretches as you described. I do not ever get “barbaric” as you put it, however I will do knee extension PROM. I never push through spasms and I always start with something pain relieving and alternate uncomfortable stretches and mobs with more comfortable treatments. It’s important to go slowly with mobs and PROM and hold for longer times at low loads to avoid having the patient never want to come back. As is also the case with rehab following this surgery there can be adequate joint mobility in the tibiofemoral joint with less patellar mobility, as Snippets mentioned, but muscle guarding and spasming prevents the pt from achieving full EXT. I use the AP joint mobs and patellar glides but I also do positional release and strain counterstrain to the hamstrings and gastroc and this is helpful and BONUS the patient feels a little better. Prone hangs with light weight alternating with MFR and positional release. Weightbearing seated or standing hamstring stretches. I have also found with patients who have a hard time with their ROM that I check the ankle and hip for limitations and do manual therapy accordingly.

    1. Good comments overall!
      Snippet, I agree with the patella mobility…didn’t include that in my post. I love it how the patient hates doing it though…Its like asking them to touch their eyeball! I also like the idea of giving them a goal and if they don’t meet it in say 2 wks…then you will have to be more aggressive. I agree with you that it really pushes them to do HEP. I also mention along these lines that they had to agree to PT in order for the surgeon to do the surgery. Not sure if this is always true but puts it back on their surgeon being upset with their adherence to HEP and overall outcome.

      Monique, great points too! Adjusting pain reliving and uncomfortable exercises is a very good approach. Just like we don’t want to work RTC for 4 straight exercises and then work on scapula retractors…need to switch things up. I agree too about going slowly at first b/c people do have horrible ideas of what we will do to their knee from friends or family. As with you’ll, I like to let them put the ball in their own court.

      Any luck with dynamic splinting? Or, do you feel it is just another product for sale?

      Thanks again for the feedback, VERY good information!

  3. Good post. Working in home health and seeing numerous knee replacement patients I see a problem with compliancce in this area. I simply the program as much as possible with self stretching activites as you have shown.

    I do not include retro walking however unless I am present.

    I have have not had much luck with dynamic splints and do not push these myself.

    1. Richard,
      Thanks for the comment. I am glad that a PT with Home Health experience has replied. I have a question for you concerning your typical physical therapy approach in home health. What I find is that patients come to me with most exercises facilitating flexion and oftentimes actually quote their flexion ROM value to me with glee. However, no one tends to state their extension value.

      My concern is that flexion is pushed and pulled to get to certain values that we forget that having full knee extension is key to most function that most patients finally yield to having surgery: and that is walking and standing. Lacking the last 5, but even 10 degrees of knee extension is key to being, well to make it simple, “straight”.

      What are your thoughts? Are there 90 degree at 3-week, or 105 degree at 4-week values that you have to meet?

      Looking forward to your response,

  4. Love this thread! Too often therapists neglect terminal extension ROM for the sake of ‘getting that knee to bend.’ I would disagree with “daily low-load, long-duration stretch” approach. Mckenzie has it right with his approach of repeated motions to end range. It does not have to be violent in nature, but IT MUST BE TAKEN TO END RANGE. 10-12x every 2-3 hours to end range holding for 1-2 seconds. Exposing joints/tissue to this repeatedly every day will allow for remolding to occur. The bottom line is how THE PAIN BEHAVES TO DETERMINE FREQUENCY, INTENSITY ETC. For example, a pain response should be created while taking the joint/tissue to end range. The pain should abate when taking the stress away (just like bending your finger all the way back, it produces sx at end range then let go and the pain goes away). If the pain persists and/or becomes more constant, then adjustments need to be made as that is an inappropriate response. Progression of forces can be made as well as dictated by response over time.

    The dynamic splinting is counter intuitive in my opinion. You position the tissue, place it under stress, and hold it there. Then the patient has complains of increased pain, now it is constant and wakes at night. All of these signs indicate tissue damage.

    Patient education is so huge here as it becomes their responsibility to ‘fix it’. Coming 3 days a week for X weeks is not going to cut it. The area must be exposed daily and frequently. The patient needs to understand this as well as appropriate and inappropriate responses to the repeated motions.

    Michael Knox PT, OCS, PA-C

  5. I am also looking for studies on outcomes on TKR. Specifically comparing ones that finish PT with a lack of full extension with ones that achieved full extension and looking at outcomes such as LEFS #s. Do ones that lack full extension report worse LEFS? If so, does that continue after DC? Such as at 6 mos, 1 year follow ups? Would the LEFS continue to be worse compared to patients that achieved full extension?

    I would think so. And Is their a linear relationship – The worse the lack of extension 5, 10 , 15 degress – the worse the LEFS? Would love to see articles on this. My email is orthocarept@aol.com

  6. Thanks, I’m a 3rd yr DPT student who’s had CI’s from both perspectives: 1) You have to aggressively stretch it to get the ROM; 2) Once the swelling and guarding reduce, the ROM will return.
    I’m still trying to figure out which is best.

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