Luxating patella (or trick knee, subluxation of patella, or floating patella) is a condition in which the patella, or kneecap, dislocates or moves out of its normal location. Patellar luxation is a common condition in dogs, particularly small and miniature breeds. The condition usually becomes evident between the ages of 4 to 6 months. It can occur in cats as well, especially the Domestic Shorthair. It also occurs in humans, where it can be associated with damage to the anterior cruciate ligament.