A method of persuation or intimidation that originated from the I.R.A. (Irish Republican Army) where a person is held down and someone takes a 2x4 piece of wood with a nail stuck through it and beats the victims knees with it untill they rip his/her knee cap off or permanently damage it so they can never walk again and undergo serious pain and agony.

The act of breaking someone's kneecaps to prevent movement.