Patellofemoral syndrome is pain at the front of your knee, around your
kneecap (patella). Sometimes called "runner's knee," it's more common in
people who participate in sports that involve running and jumping. Pain
usually causes a dull, aching pain in the front of your knee. This pain
can be aggravated when you walk up or down stairs, kneel or squat.
Sitting with a bent knee for long periods of time can also cause aggravation to the area.