What kind of injury do I have to my leg/knee?

I was playing softball and running to first base... felt a pop on the backside of my leg down in the general area behind my knee and on the back outside portion of my knee (not the MCL or LCL from what I can tell).

There wasn't any acute pain associated with the pop and I didn't hear anything, just felt it. There doesn't appear to be any swelling or discoloration -- just some difficulty in moving it, as it is pretty sore. As of now, the joint doesn't feel unstable, either.

Could this be a lower hamstring injury or is it something to me knee? Any ideas?

It could be a number of things, and I鈥檒l be upfront with you that any sort of accurate diagnosis over the internet is almost completely out of the question. But from what you said I鈥檒l give you my 2 cents.

Your report of a 鈥減op鈥?indicates something broke. Considering that you were engaged in running bases, an explosive, high force activity, at the time certainly would support the 鈥測ou broke something鈥?theory.

Considering the area (the distal posteriolateral thigh), your reports of good knee stability, and a lack of swelling/discoloration ligamentous damage can likely be ruled out.

Likewise, lack of swelling and discoloration, and no mention of any clicking, catching or buckling likely rules out a meniscus tear.

So let鈥檚 go back to the area. Your lateral hamstring, the biceps femoris, runs right about where your 鈥減op鈥?was, and lots of people end up 鈥減ulling a hammy鈥? With what you鈥檝e said, that鈥檚 what I would say you鈥檝e got--- a 1st degree biceps femoris strain. Signs and symptoms would be pain and pain potentially limiting your active range of motion and strength, but no true loss of strength. If it was a 2nd degree strain you鈥檇 have the pain, but would also notice some significant muscle weakness.

Alternatively, if you鈥檝e had a history of hamstring strains this could have been an adhesion (scar tissue) breaking.

In either event, ice is your friend. Ice the area down (stick a bag of frozen peas on it) for 20 minutes, wait an hour or two, then repeat. Rest it for a while. No strenuous exercise. Walking would be ok, and probably good for it, so long as it鈥檚 a nice relaxed pace. Take some ibuprofen or other anti-inflammatory over the counter medication to keep any inflammation down.

Again internet 鈥渄iagnosis鈥?= not really worth much. Still, I hope this helps. If the pain hasn鈥檛 gone away in a few days, go see your physician.

Have a good one.

A couple of quick things come to mind. You may have just popped it out of place quickly and then it returned causing the ligaments to stretch briefly which would explain the pain around the knee. Another possibility is a common cyst that popped behind your knee called a Baker's cyst. If this is the case, no harm caused, just some discomfort.

Go to WebMD and use the interactive symptoms checker. Pretty cool, not funded by Big Pharma, just useful advice and suggestions about whether/when to see a doctor.