fixed gear knees

So heres the deal with my knees.  For my entire life I have had no problems with them.  I figured I was like robocop or something, indestructible if you will.  Polo has been really hard on them.  Really its two to three hours of grinding on my knees as hard as possible.  There was however one instance that triggered my knee troubles.  While playing polo, I collided with another gentleman's pedal bike and rammed both knees into his bike.  I'm not quite sure how I managed to hit both of my knees, but I do know I hit the right on harder.   So we continued to play on, (shake it off son) after a bit there was another collision where my front tire was taco'd.  And hey its not like I go around crashing, but it happens,  those boys in Manty go balls out.
       So,  my knees are injured and my bike is down.  What do I do?  I borrow a fellows  bike to finish the two games.  The only bike available for me had an extremely high gear and was way to short for me.  So my legs are pushing hard and not getting anywhere near the proper extension.    "Dig deep"  I hear from I team mate.  And I do.  I finish the night out with aching knees.    Mistake.   I should have stopped right away. 
      That was three or four weeks ago and my right knee in particular is f'ked.   I am deeply concerned that I have caused myself permanent damage.
   I did find this tidbit today,

"Across the board, it is universally accepted by medical experts that high-gear, low-cadence pedaling has a high likelihood of causing knee pain and permanent injury. The main preventative measure as well as primary remedy for that problem is low-gear, high-cadence riding, which is only possible with the ability to change to appropriate gears throughout a ride. Fixed-gear riders are unable to avail themselves of that remedy, and because of that, they experience more frequent and higher pressures on the knee than a rider on a bike with gears."

Here is my take,  I have been riding brake-less for three plus year and for what??  I through a front brake on and it is much nicer.  Forget that whole macho brake-thing.  I like my new brake.

Now all I need is a larger cog ;)