Dealing with weird sensations after ACL surgery

Posted on September 27, 2017

(Last Updated On: September 27, 2017)

The weird feelings you may experience

I’m going to describe sensations I, and people I’ve worked with, have had. I’m going to use my personal experience more though. I feel that will better resonate. We’ll go through it as a timeline. From immediately post-op, to five plus years later.

Feeling the new ACL graft

The graft is the new ACL put in your knee:

Because I started rehab the day of surgery -which everybody should be doing!- I did some quad sets within hours after waking up.

Every time I squeezed my quad, I could feel that new graft in my knee. It was Freaky. As. Hell. The exact orientation of the graft, the location, I could feel all of it. This went away within a few days, but was one of the most noteworthy sensations after surgery. I imagine it’s what Wolverine felt like after his adamantium transplant.

Phantom / dual limb

This started a week after surgery, when I started to walk more without crutches. (It took me ~4 weeks to be fully without them.)

As my surgery leg’s foot hit the ground and swung to take the next step, I would feel as if my leg was actually 12 inches out to the side. That is, I’d be walking in a straight line, yet it felt like the leg was a good 12 inches wider than that line. As if the knee was floating in mid air. I imagine it’s what using The Force feels like.

This lasted for a few weeks.

The random jolt

Once every few days, maybe once a week, could be while walking around, getting up from sitting, something completely innocuous, I’d get a “WHOA! [some panic sets in] What the FUCK was that?!?” It could be anywhere on the knee. I distinctly remember getting a lot of these sensations around the top of the fibula.

Yet in my surgery, and a great majority of ACL surgeries, nothing was surgically done to, or even around, the fibula. We’ll go over why this can happen later on, but random jolts, feeling as if something just moved, are typical.

It was like this scene in Varsity Blues, but with a hell of lot more panic from Tweeder at the end:

Stabbing hamstring pain

Part of my hamstring was cut to be used as the new ACL graft.

For a year, I had once every couple week stab sensations in that hamstring. One time I was walking by a park, completely fine, then it was like someone grabbed my hamstring as hard as they could and wouldn’t let me move. I had to sit down for about 10 minutes, then I was fine. But I briefly thought the guy from Scream had finally found me.

This slowly lessened in frequency. By the two year mark, I’d say it was once every few months. However, I then started doing a lot more sprinting as part of my workout. It would happen maybe once every five sprint workouts. Where mid sprint I would feel it, stop, then be fine five minutes later and keep working out.

It was as if I suddenly strained the hamstring, then it healed in five minutes (which means I didn’t actually strain it).

By the five year post-op mark, this had vanished.

Hamstring (gently) snapping

Specifically when doing these two exercises, which stretch the hamstrings:

If I went all the way, I’d often feel the medial (inner) hamstring, again, where the graft was taken from, gently snap over my knee. I’d bring the leg back, and it would go back. This was never painful.

By five years post-op, this also disappeared.


One day, 18 months post-op, while doing something which involved bending my knee, I had an unignorable, crunching, sandpaper, F-150 driving-over-gravel-commercial sound. This proceeded to happen whenever I would deeply bend my knee, or straighten it from a deep bend.

This became so noticeable it grossed my girlfriend out. She would shiver or recoil upon hearing it, then toss me into my lair until my ugliness had dissipated.

It was loud enough she could hear it when I would e.g. get out of bed in the morning. It was like a reverse Beauty and The Beast. Where she became progressively uncomfortable around me.

This was also never painful. And it was not arthritis (I had X-Rays, and a follow up arthroscopy for my meniscus confirming no arthritis)-

What’s up with the noise my knee makes?

This was pronounced for a year. It then progressively lessened, to where it was barely noticeable five years post-op.

Dragging my foot

Notice the difference on the front of my right shoe vs my left:

(Right shoe is left image.)

You can see it’s more worn down higher up on the right toe box.

Once every few days, while walking, I will drag my toe into the ground. It’s as if my body starts swinging the leg forward, then forgets to bring it all the way. It’s quite annoying.

I could very well be more aware of this now compared to before having surgery, where it may have always been there. But I doubt it. (I don’t have any shoes laying around which are 5+ years old to check.)

Knee feels, and is, shaped differently

Where I had the screw inserted:

there is a noticeable bump on my knee. The screw has been removed, so that’s not it. It’s bony growth.

That’s the bottom side drill hole. On the top side drill hole,

I swear the knee is bigger there as well. If you think about screwing into wood, the wood, even if it’s ever so slightly, expands to make room for the screw. I swear I can feel, with my hands, that expansion.

The “is fluid in my knee?” but there isn’t

This is the weirdest one. Randomly, pretty much every day, I get a feeling there is some tiny amount of fluid moving in my knee. I could just be standing in place, and will start to feel it. It’s bizarre. I don’t actually have any swelling, and I can’t feel anything with my hands.

What you don’t want to be feeling

The majority of time, when someone is feeling weird sensations after ACL surgery, it’s nothing to worry about. It’s part of the process. When you have your body cut open in four places, drilled in two, have the inside of your knee and thigh sewed and cut off, shit’s going to feel weird.

However, there are two sensations where I immediately tell the person to check with their orthopedist.

  1. Locking of the knee
  2. Giving way

If the knee locks on you, like you can’t straighten it for a minute, red flags go up. Something is impeding the knee, which is not good. Note some random catching here and there, where it happens for a split second then you’re ok, can be normal. This goes with the jolts sensation I described. A locking is much more pronounced. Like “SON OF A BITCH I CAN’T STRAIGHTEN MY KNEE!!!”

Giving way is where the knee all of a sudden falls out from under you. Where you’re on the verge of hitting the ground before you compose yourself. This is essentially the sensation ACL patients are most familiar with- the instability. This is why you got the surgery. If it still happening post-op, that graft and new ACL needs to be checked. It may be you need more time and rehab, but it also may be that graft isn’t doing its job.

Why the sensations


This is the predominant cause of the random jolts, “what the [insert thirty expletives] was that?” moments. For a long time after this surgery, can easily be three months, six is not out of the question, there will be some swelling. That will initially be from the surgery. As time goes on, you’ll have times you do too much, such as push therapy too hard, accidentally causing the knee to swell. It will take a while to get a handle on this.

In the mean time, just imagine that fluid moving around your knee. It’s going to move under tendons, between ligaments, flush through fascia. It makes sense one moment, all of a sudden fluid rushes from one place to another, and pop / snap / crack. Just like cracking your fingers happens.

Knuckle cracking.

This is why tendons might not feel like they’re gliding the same way. Because they aren’t!

Bone shape

I hit on this one already. If the bones change shape around areas where stuff likes to move, for instance, the top hole I outlined earlier is by the IT band, then those bands might feel weird from time to time. They are gliding over an area that didn’t used to be there.

Front of the knee; side of the knee:

Nervous system

Personally, my hunch is where the incisions occurred confused my nervous system. Whether that’s a little nerve damage at the skin, I don’t know. But those times of “is there something on my knee? Or is something moving around inside my knee?” is where a confused nervous system comes in. To where it’s practically indescribable.

There are multiple ways I know this is nervous system oriented. I’ll go over the big reason in a second.

Handling the sensations


Pretty basic here. Be patient and the sensations will work themselves out. We humans more often than not can acclimate to a new environment. Whether that’s externally or internally. But we need some time to do so.

-> Easier said than done! When I woke up and felt the graft in my knee, I momentarily freaked out, thinking I was going to feel that for the rest of my life. Then the drugs recirculated and I fell back asleep.

Proper rehab

A big part of all the above is getting used to your new knee. The best way to do that is use the new knee!

Of course, after surgery, we have to be aware of how much, how fast, how hard, how much range of motion, and on it goes, we use that knee.

-> Here’s some help with that.

But waiting 2-4 weeks after surgery to start post-op is a classic mistake. You’ve now elongated your adaptation time.

Part of rehab is getting your brain and knee to communicate with one another. The brain is used to certain anatomy. It’s going to need practice to acclimate to your new anatomy.


Put something around the knee

A wrap:

-> How to wrap a knee

a knee sleeve, or pants will help. (Check out the link above for more on sleeves though. I prefer wrapping or pants.)

This is the big way I know -for me- the nervous system is what’s still off. If I wear pants, I cannot feel any of those indescribable sensations. The pants provide two remedies.

  1. Distraction- Instead of feeling whatever around the knee, I feel the pants touching my knee. It’s like trying to listen to a conversation when traffic is going by. The traffic drowns out the conversation. In my knee’s case, the pants drown out the conversation in my head of “Is that fluid in the knee? Should I rub my knee to check on it?”
  2. Proprioceptive feedback- Think any time you hurt an area. We almost always, naturally, touch or rub that area. My belief here is we’re trying to get feedback on how the area is, to gauge a response. Most of the time, the area may be hurt, but we realize it’ll be ok. So touching it makes us feel better. For those who’ve had a catastrophic injury, you may have touched the area and only freaked out more. (I did this upon realizing my elbow dislocated.)

One of the hallmarks of phantom limb pain is mirror therapy. If someone doesn’t have their left hand, but they look at their right hand in a mirror, the phantom limb often feels better. They give (trick) the brain a signal of “Hey, the limb is here, and it’s ok.” I bet that’s what wearing pants can do. Something has been disrupted between the signaling of my knee and brain. Multiple times per day then, my brain says “Hey, check that area out and confirm everything is ok for us.” The pants constantly rub the knee, which tells my brain my knee is ok. Everything is where it should be.

I’m currently in the middle of simply wearing pants as often as I can. I’m curious if after doing so for a while the sensation will go away. Worst case, with all the pants practice, I enter a new club.

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