Causes
Mostly congenital/genetic, due to an abnormal alignment of the joint. Predisposed breeds: Yorkshire Terrier, Chihuahua, Poodle, Pomeranian, Bichon. It can also be traumatic.
Diagnosis
Physical examination (the vet feels how the patella moves and grades it from I to IV) plus X-rays.
Treatment
Mild grades: weight control, appropriate exercise, joint supplements and monitoring. High grades or those with pain: corrective surgery, which has a good prognosis.
Prevention
Buy puppies from responsible breeders, avoid excess weight, and limit jumps from a height in predisposed breeds.

