in the rubbery cushions of the knee joint (menisci).
Breaks (fractures) of
the kneecap, lower portion of the femur, or upper part of the tibia or fibula.
(See an illustration of the
structures of the knee.) Knee fractures most commonly are caused by abnormal force,
such as a falling on the knee, a severe twisting motion, severe force that
bends the knee, or when the knee forcefully hits an object.
dislocation. Pieces of bone or tissue (loose bodies) from a fracture or dislocation may get caught in the joint and
interfere with movement.
Grinding may occur with joint movement because of other conditions,