Lump on tendon at knee...?

[SynthiaL]

I ran for years, had an accident in 1996, crushed right leg, femur is now a metal rod (inside the bone), and there is nerve damage/some numb spots, but I haven't had many problems, until I twisted my knee the other day while jogging, lots of pain, went to the doctor, he said I had cartilage damage under the kneecap and to give up jogging and just swim for exercise. Ok, but my knee really feels weird, and now I noticed a lump on the tendon just above the knee, in the back, about a half inch under the skin surface, feels like it is attached to the tendon at the outer edge of the leg, it is the size, shape, texture, density of a pinto bean. It doesn't hurt to move it - but it can't be moved much. Any ideas?
Thanks
Synthia

[Heidi]

Is this lump painful? Does it hurt to push on or is that where the pain feels like it is coming from when weight bearing or moving the leg?

What activities or movements do cause pain?