Kneecap Injury What Injury Of The Knee Is Associated With Pain Behind The Kneecap And The Inability To Fully Extend The Leg?

What injury of the knee is associated with pain behind the kneecap and the inability to fully extend the leg? - kneecap injury

I think I hurt my leg when sprints in football. I had not played for a while, and I think that was the cause. Is it an Achilles tendon injury?