Luxating patella

Luxating patella (plural luxating patellas or luxating patellae) is a condition in which the patella (kneecap) moves out of its normal position in the centre of the kneecap. In humans, the problem is commonly called trick knee.

Luxating patellae can occur in dogs and less frequently, cats. In canines, it is associated with small and miniature dog breeds and is believed to be genetically linked, although it can also be caused by injury ("blunt trauma").