Bridge pose is great for working the quadriceps, abdomen, and lower back. It can be sometimes difficult for those with knee issues. A great alternative to try is doing your "bridge" on the wall. It puts less stress on those ligaments around and within the knee.
To do this: Position yourself around a foot away from the wall on your back with the feet pressed against the wall. Your shins should be parallel to the floor, so adjust accordingly. With feet pressed against wall, lift pelvis up like you would in bridge and adjust so that the shins remain parallel to ceiling. Keep your head on the ground, but tuck that chin to the throat to work that thyroid gland. You can use your hands to press against the lower back to deepen or stabilize your position. Stay in it for 5 to 10 good breaths and come down. Repeat as desired. When done, counter the pose by bringing knees to chest and rock side to side. Great inversion with less stress on the knees...but still working that body in the right places!