An x-ray of the kneecap would be helpfull.
Swelling, tenderness to touch, discoloration, painful movements...just a few to name.
You can't instantly tell that your finger is fractured, as with me, because right now i am suffering with a fractured middle finger. There are some symptoms assoicated with it though. In my case my...
You will will a lot of swelling, and it will no signs of recovery after the first few days. See a Doctor as soon as possible.
An obvious deformity; otherwise an x-ray is needed to know for sure.
Waffles.
If it swollen, painful if you try to move it and it feels quite numb.