Definition of Patellar Luxation
Patellar luxation, commonly called a “slipped knee cap,” refers to dislocation or displacement of the patella bone from the knee joint. This is one of the most common canine knee problems. Patellar luxation can exist at birth or be acquired later on. Genetic and developmental factors can contribute to luxating patellas by altering the alignment of the shin and thigh bones as they meet at the knee. Trauma to the bones or tissues surrounding and supporting the knee can also cause patellar luxation. Most cases are probably hereditary. Patellar luxation is prevalent in miniature and toy breeds, although larger breeds can be affected. Luxating patellas cause mild to excruciating pain. Affected dogs become lame in the rear and may develop an odd skipping gait. They often have trouble standing up and are reluctant to run or jump.