Where can a knee cap shifting out of place go?

Lateral knee: A knee cap that subluxes or dislocates will almost always do so laterally and will sit on the lateral plateau of the tibia. It will be painful but generally a forceful contraction/flexion of the knee will pop it back into place, and it will bump against the lateral knee and cause pain, swelling and a possible bone bruise. Expect lots of swelling in the knee after a dislocation or subluxation.

Lateral : Nearly all knee caps that shift out of place (dislocate), go to the outside (lateral) side of the knee.

Laterally.: If the kneecap is dislocating, it usually dislocates to the lateral side of your knee ( the outside part of your knee).