Knee support advice?

I am an old guy (36) with a history of sore knees and a partial ACL tear. Sometimes I can go weeks without any problems, but others (like now) my knees are killing me from doing drills in someone's guard.

Can anybody recommend a good knee support or pad for BJJ? Any opinions on padded vs. open patella? Are there some that allow more flexibility than others (e.g., so I can still do a triangle)?

I have been looking at wrestling knee pads, but I have no background in wrestling and don't know if these are flexible or not.

Thanks!

edited because posted wrong link:

http://www.mma.tv/TUF/index.cfm?ac=ListMessages&TID=385793&FID=1

Thanks for the link. I think I'll try the Asics gels.