Although my right knee joint has decided to be a bit difficult...
I honestly think the indoor tracks are really bad for knees.
I have bad knees but they never bother me as much as they do when I run on indoor tracks.
I am mixed on this. On one hand I don't have to deal with the elements and uneven surfaces, but on the other hand I have idiots who play basketball who decide to congregate in the lane I want to run in. I feel like plowing them over and having them thrown out, since I am faculty at the college I run at, but cooler heads prevail.
Also I haven't decided whether a banked or unbanked track is the best. I ran on unbanked tracks and had lots of foot and knee problems, but on a banked track I had problems with speed because I always was nervous hitting the high bank.
As it gets colder outside, I just deal with running on the indoor track and treadmills.