Until very recently, cats were not thought to be affected by hip dysplasia. Well known in many dog breeds as an inherited disorder, cats were felt to be free of the condition. New information and research has shown that this disease does indeed exist in the cat and is likely an inherited disorder. No single gene is thought to be responsible for hip dysplasia in either the dog or the cat, but rather a complex interplay of several genetic factors is involved. We do know that if a cat or dog is found to have hip dysplasia, then both its parents must be either affected or carriers of the defect. Using new information, cat breeders are able to develop breeding programs to minimize the incidence of this problem in their breed.
Hip dysplasia is a disease of the hip joint. “Dysplasia” is a word that means abnormal development of a tissue. The hip is a ball and socket type of joint. The “ball” is the top of the femur (called the “head”) which fits into the “socket”, the depression in the pelvis called the acetabulum. A normal joint has a close fit of the femur’s head into the acetabulum, so that the joint functions smoothly and efficiently. The large muscles of the hip and pelvis help hold the joint in place and allow it to function properly.
In hip dysplasia, parts of the hip joint are abnormally shaped, so that the fit of the ball into the socket is poor. This allows the head of the femur to move easily out of the joint to some degree (called “subluxation” = dislocation). Over time, chronic changes develop in the bones of the hip joint from this abnormal movement and degenerative joint disease may result. In most cases, both hip joints are affected although one may be more severe than the other. Many cats with hip dysplasia go undetected. Due to their small size and the fact that cats are not exercised as much as dogs, along with their natural agility, they may have hip dysplasia and still function normally. In some cats, hip dysplasia is found incidentally when they are x-rayed for another reason. This disease is not obvious at birth, but develops as the young kitten grows.
Some cats with hip dysplasia, especially the more severely affected, will have obvious symptoms and experience pain. ..... [Read complete article]