I am a 22 yr old male.
About 14 yrs ago I damaged my Meniscis whilst playing Soccer, since then i have had many knee problems as i played contact sports such as Rugby until the age of 19.
In the last month i have noticed a "bone" on top of my left patella (knee cap), it is about 10mm long (down) and 5mm wide (across). When feeling it, it appears as if I have "chipped" the bone, as it feels like there is the "hole" from this bone next to it.
It does not cause me any pain, but it is SOLID, and can be noticed on the surface. I dont know how long i have had it for!
At the moment the only pain I have is on a tendon (I think) on the outside of my left knee, running up about 20cm of my leg. But i do think it is unrelated.
I have searched the internet but cannot find anything similar to what i have on my knee cap.
You may have chipped a part of your patella or been born with an extra piece that was dormant until this time in your life...Our son was born with three knee caps...When he was 19 years old he was operated on and two of them were removed...If it bothers you then have it checked out...Otherwise don't worry about it....Good luck with all the sports...Take care...