Knee locking after ACL reconstruction

Hello all I’m hoping that there someone out there that can help me and hopefully put my mind to rest. I injured my left knee back in August 2017 whilst playing American football. There was no contact made just purely trying to change direction whilst sprinting, my leg twisted but my foot stayed still and I heard the bones crunch.

After an MRI scan I was diagnosed with a ruptured ACL, sprained LCL and damage to my cartilage. I was advised that surgery would be my best option for the ACL & cartridge, which I had on the 13th November so it’s been just over 2 weeks. (Still early I know). In my rehab I was advised to concentrate on getting swelling down and trying to get movement back into the knee. In my first week I managed to get movement to 90 degrees and was off my crutches and given some more exercises to work on.

This is where I started having problems. The swelling hasn’t reduced any, I’m still limping and the knee is still constantly painful. However more worryingly when doing the exercise of raising my leg whilst having a towel under my thigh my knee locks! It locks so much I need to force my foot down with my hands at which point my knee cracks and is horrendously painful. When telling my NHS physio this on my 2nd appointment he got extremely worried and advised that he’d make an emergency appointment with my consultant. However I’ve not heard anything regarding this and it’s left me pretty worried and demotivated on my rehab progress.

I’m hoping someone out there will be able to give some sort of advice.

Many thanks for taking the time to read this.

I tried to reply to this yesterday but ended up getting duplicate messages and was unable to edit them sufficiently. So here goes again.
Please make sure any bolster of not in the bend of the knee. There are good reasons for this but not necessary for this part.
There can be many reasons for the patella to snag and make it difficult to bend your knee I'll briefly mention a couple but rest assured that is fairly common.
The quad could be tight restricting inferior movement of the patella into the trochlear groove of the femur. The lateral peripatellar soft tissues(retinaculum, ITB,etc) could be tight, swollen, and have restrictions limiting the normal inferior and medial movement of the patella into the groove.
You probably need lateral thigh soft tissue flexibility in a manner that doesn't produce pain or increase swelling and some medial thigh muscle recruitment of the hip Adductors. If the femur lays rotated out this can exacerbate tightness causing a pull on the outside of the patella. Normally we also have some medial thigh muscle strength to counteract that to some degree but after surgery that declined significantly. You can have an imbalance between tightness on 1 side of the thigh and weakness on the other.
All too often people focus mainly on the knee extensor mechanism and not near enough in the hamstrings and surrounding thigh muscles.
I have seen the biceps femoris hang up on the fibular head but that is not common and from your description probably not even close to the problem.
You may have to manually move your patella before movement until these issues are resolved but that shouldn't be too long.

Hi Finchr,

Thank you for your reply and advice it really has helped put my mind to rest as I was getting worried it was more the surgery hadn’t worked. Now that you’ve said that it will more likely be the muscles causing the issue as I have had problems with my hamstring ever since the surgery. I am seeing my physio tomorrow so hopefully will find out more however I am having so many problems with my hamstring that I am struggling to perform squats.

After surgery it is not all about strength but decreasing swelling and increasing flexibility. The lateral thigh really needs to be stretched. Listen to your therapist and good luck. Don't try to rush the healing process. It takes what it takes

Have you tried a stem cell treatment? I am a personal trainer and I had a terrible pain in my knee. I kept waking up with pain after an injury; just going to do my shopping was painful. I had to have a knee replacement surgery recently with Dr. Zanasi, I was really happy with the treatment. The recovery was really fast and now I can do my normal activities, as there’s no downtime with this kind of treatment. I highly recommend him, this is his website Home – Dr Zanasi Stem Cells
Best wishes
Sam