Knee pop - ACL tear?

I've heard some say tearing the ACL is painful, others have said they didn't even know for a little while.

Definitely get it x-rayed.

My knees pop all the time and have just about my whole life so for me it's just the way it is.

 

Surely it depends on the severity of the tear? Anything substantial, and you would be rolling around on the floor in pain. And if you try to stand on it, well, you won't. Saw a guy get carried off the soccer field with an ACL tear the other weekend. People 15 feet away heard it "pop". He will be hobbling around for at least 3 months, likely 6. Your pop may simply have been tissue squeezing an air pocket or muscular action causing tissue to move over a bump and snapping into place...a lot of people's elbows click or snap for the same reason. If it was an ACL tear, you are lucky in that it seems like most of the ligament is still attached.

 

Having had a major ACL and MCL injury, I'm somewhat qualified to answer. But, I'm no orthopaedic surgeon. Always best to get a professional opinion when in doubt.

First, if it's a tear (complete or partial), there will be hemorrhaging. And, that means swelling. So, that's the first tell-tale sign. If there's no swelling, there's VERY mild damage (if any at all). Second, soreness. Without it, you're probably fine. Icing will help both swelling and soreness, of course, but a serious injury will have other symptoms. Third, I might disagree with the comment that it's painful. Mine wasn't, despite the severity of the injury. Many can function without pain and have reasonably good stability even without an ACL. Although, bracing would certainly be helpful and prevent additional injury to the meniscii. Some have even torn it without knowing! Fourth, the stability test will give you a better indication. An orthopaedic guy can test it quickly. Or, more crudely, you could test the lateral strength by doing some light lateral cuts on it. I wouldn't recommend this approach, though, because it has the potential to damage other ligaments as well as the meniscii if the ACL is indeed torn. Fifth, if problems persist, an MRI is more useful than an x-ray. The soft tissue injuries don't show up well on x-rays, although hemorrhaging does. So, the x-ray might indicate a need to do an MRI. But, I generally would just get the MRI. You'll learn more from it, anyway.

CW

 

You should be fine. However, if you have any remaining concerns, contact a specialist to at least have a physical exam.

Good luck.

CW

 

I had (have) a partially torn MCL from getting speared by a ball-crazed dog. I had no idea I had damaged anything. After a few months I noticed some problems running and some instability snowboarding. The doc sent me for an MRI and, sure enough, there it was.

Some can get on just fine by knowing it's there and not overdoing certain activities but a thorough exam and MRI will give you the full picture.

 

Sometimes once the knee has suffered damage just a change in barometric pressure will effect it. The knee will feel like it could give out at any moment until the barometric pressure changes again. Then the perceived strength will once again return to the knee. Probably if you are under 55 this won't be an issue however...
CH

 

I formerly practiced physical therapy. The typical mechanism of injury for an ACL tear is when the foot is planted and there is a twisting motion at the knee joint. A full thickness tear will normally have substantial swelling and substantial pain when the injury occurs. An external test to verify an ACL tear is the anterior drawer. This needs to be done before swelling occurs or after swelling has subsided for accurate results. The more definitive way is a MRI which notes soft tissue structures such as the ACL, PCL, MCL, LCL, meniscus, and articulating cartilage.

The popping the original poster experienced felt/heard could have been a number of things:

1. A full or partial thickness tear of a ligament ( ACL, PCL, MCL, LCL ).

2. A stretching of the aforementioned ligaments.

3. A meniscal tear

4. Air that was being forced through the synovial capsule similar to the noise/sensation one gets when popping their knuckles.

From the original posters subsequent posts it appears it may be the latter.

An individual does not need to have the ACL reconstructed. There are fabulous braces on the market that provide more than adequate stability. John Elway played without an ACL. Some injuries stretch but do not tear the ACL. They create instability and can be corrected through a procedure called thermal shrinking. This procedure heats up the ligament and shrinks it making it more taught.

Ways to self identify a possible ACL tear is difficulty with fully extending the knee, instability, an abnormal gait pattern and/or persistent swelling.

To make sure there isn't a significant problem it is always best to visit the primary care physician.

I hope this helps with some insight into ACL injuries.

 

Costanza had that.