MCL injury and wearing a Knee Brace

Hi,

I searched the forums to see if this topic had been covered and couldnt find anything so here goes.  Last winter I tore my MCL while snowboarding (freak accident) and my Dr said I need to wear a DonJoy Defiance III knee brace for sporting events for the next year or so.  I've run and biked w/out it and it still hurts so I need it for that.  Swimming is also tough, I end up not kicking as much. 

My question - does anyone have any experince w/ this kind of brace and if it would be allowed during the swim portion because it has hard metal/alloy?  and could it pose a risk if someone bumped or kicked me?  Thanks