What do you think is wrong with my knee? a little over two months ago, i fell really hard on my knee playing basketball. it swelled a little, but never bruised. it still swells sometimes when i run on it and hurts when working out and playing basketball.

Understanding : Understanding that i would like more info to answer more accurately, i am concerned that you can't fully bend or extend your knee you may have fractured your knee cap or torn your patellar (or less likely) your quad tendon. To clarify, can you fully extend or flex? Does pain limit the flex/ext? Or is flex/ext not possible in any circumstance? Other considerations include torn, unstable meniscus and ligament tear. I recommend evaluation by a local orthopaedic surgeon at your earliest convenience.