5 ACL Injury Symptoms

Like many of us, my athletic glory days are likely behind me. I enjoyed several sports competitively with a heavy emphasis on skiing. Seeing many teammates go down with badly torn knees I thought I knew what ACL injury symptoms were. See the 5 most common ACL injury symptoms below…

From both witnessing many teammates with ACL injuries and now my own two ACL tears and surgeries I am confident I can share with you what the common ACL injury symptoms are.
After abusing my knees extensively and exiting my youth with no knee problems to speak off I really felt I had been lucky enough to have a pair of knees that would continue to be problem free.

My ACL Injury

When I was 23 at University I was playing on a club Rugby team for the 2nd year. During the start of the 2nd year we were having practice and playing a simple touch rugby game. It was a freshly cut, dry and level field and half way through the game I went to make a fake to my right side and hard cut to my left and when I planted and cut on my right foot I felt a pop and immediately fell to the ground.



The pain was moderate, my knee didn’t feel “right” but I couldn’t figure out exactly what the problem was. I sat out for about 15 minutes and then got up and walked a little, it still didn’t feel right so I decided to head home before my knee started to seize up more. At this point there was no swelling to speak of, minimal pain and the only indication that something was off was the instability I had when I was on my toes on my right leg. Unfortunately, I had a 4 mile bike ride home where I mentally agonized over what I may have done to my knee. I kept running all the possible ACL injury symptoms through my head.

At home I followed the standard RICE protocol for a couple of days…
R – rest
I – ice
C- compression
E – elevate

As I tried to run through the symptoms of what could be wrong with my knee I dismissed a torn ACL since there was almost no swelling and very moderate pain. From seeing teammates destroy their knees and tear their ACLs skiing I did not believe my knee problem could be that bad.

After 1 week I was having instability issues and the pain, although moderate, was not getting any better therefore I decided I had no choice but to get my knee looked at by a doctor.

Misdiagnosis of ACL Injury Symptoms

Although I saw a sports medicine doctor she compared my two knees and felt that my ACL was not torn and had only bruised the meniscus. I was happy to hear this even though I didn’t fully believe the diagnosis since I didn’t feel it explained the instability issues I was experiencing.

5 Months After ACL Injury
The pain in the knee stays about the same for 5 months, there was minimal swelling but I was able to do most activities I enjoyed including biking, running, squash and skiing. The instability issues seemed to be manageable and I was able to function pretty well. When I returned to skiing my knee would give out once a weekend but wouldn’t cause very much pain when it occurred. I was convinced something more must be wrong and I would have to get an MRI to know fore sure.

MRI Results
After I see another sports medicine doctor and telling her my story she sends me for an MRI. Luckily I was able to get on the cancellation list as I was living close to the university Hospital and had a flexible(classes can wait) schedule.

When I got the results it was clear, torn ACL with some medial meniscus damage.

I tell you this story because I wish I had been able to read this blog post back then and understand better typical ACL Injury Symptoms.

ACL Injury Symptoms:

The ACL injury symptoms are listed in order of relevance. For example almost all people that injur their ACL to the point of tearing it feel a popping sound and have instability issues where as not all people have swelling and pain.

  • Popping Sound/Feeling
    • When you injur your ACL one of the most common ACL Injury Symptoms is the sound or feeling of popping. This sound is quite literally your ACL popping like an overstretched elastic band. It is almost always followed by the injured person falling to ground.
  • Swelling in Knee
    • A very common symptom is that of significant swelling in the knee. Most people when they tear their ACL also cause significant amounts of other damage in their knee and the combination results in severely swollen knees. However, as was my case there was very little swelling in the knee. For me my right(injured knee) was more swollen than my left but not by as much as most people say it would be after injuring their ACL.
  • Instability after injury
    • When you have an ACL injury one of the most unique and telling sypmtoms is instability in your knee. The ACL is a key ligament that controls your knees movement. When you have injured your ACL you will find your leg “giving out” when you go to do various activities. For some people it can be as simple as walking or jogging. For me my knee would give out when I was skiing after my ACL injury.
  • Moderate to severe pain
    • Right after the injury you will feel moderate to on some occasions severe pain especially on the outside or back of the knee. This is where the ACL attaches and the feeling of pain will be coming from those areas.
  • Limited movement
    • Limited movement will be a symptom of an injured ACL since the swelling of the knee, especially the swelling inside the knee, will reduce your knees range of motion.

ACL Injury Symptoms Summary

When you injury your ACL you will almost always feel or hear a pop, fall to the ground, may or may not be able to walk after but likely cant return to the activity you were doing. The swelling and pain will both be moderate to sever and you will likely experience moments of instability.

The Top 5 At Home Exercises
I did that helped get me walking 4 days after surgery

Click Here to see the exercises


  1. Jon Haver says:

    I as thinking after I wrote this that other people may have had a similar experience with minimal swelling or some other difference which resulted in a mis-diagnosis.

  2. i had the exact same process – injured my knee in january, didn’t get the MRI until july. however, in january, my doctor said that he suspected a slightly torn ligament, not fully torn, and that a surgeon would not operate on a slightly torn ligament because it could heal itself. i’m not sure what it actually was, because i continued to have small injuries to the knee about 4-6 months after the injury, so they may have caused the final, full tear. by the time i got my MRI, the acl was completely gone.

  3. david hull says:

    I had the exact same scenario and even went back to playing rugby… I done the injury in March, knew my knee wasn’t quite right but physio said Medial ligament so I rested it and came back after 4 weeks. My knee would give way every so often. When I finally decided to go to a sports physio at the end of may he sent me straight to a surgeon and I got an MRI. Just had my surgery in September and so far doing really well..

  4. My 17 yr old daughter may have had a misdiagnosis too; I wish I had insisted on her having an MRI immediately. She plays soccer at a premier level and was playing when she dislocated her kneecap. Went to a knee specialist specializing in athletic injuries and did an xray but did not do an MRI. He did not feel that she had done any other damage beside the kneecap; rested the knee and did physical therapy for 2 weeks. She had just been cleared to begin LIGHT practicing again. Her first day back at practice, her knee went out (no pop noise) and began to swell immediately. Went back to doctor, had an MRI and now it was a torn ACL. He also discovered that her kneecap was not all the way back in place. He recommended ACL surgery and a lateral release. I just wish that he had done an MRI at the first visit, then we would have been sure about whether or not the soft tissue s had not been compromised with the dislocation.

  5. Do you have much post op pain in the knee? I’m having ACL surgery next week and getting a bit nervous now…tear happened playing football when a player fell into left knee at speed and my leg was planted. This happened end of July and I’m off work since and will be off until after Xmas.

  6. Pauls Toutonghi says:

    Thank you for this great blog! 5-days out from ACL surgery, I have to say that reading this is both informative and comforting. Seriously. This is a great public service.

  7. Hi Ashley, iam 14 and it sounds like i have done the same thing as you have done. i injured my leg playing rugby in november last year and by the sounds of it you will have to have an operation on your leg.i have had one operation on my leg and i will be having another one as well. my second operation will be on the 28th january. the rehab also takes a long time, i will not be able to play rugby again for about 8 months but i hope to be doing athletics again by March (not looking hopefull) when i first saw the doctor in december it took about half a month to get the first operation out the way, i had this operation on the 3rd of january.

    I hope i have helped you. get better soon :)

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