by Ben J. Character, DVM
Hip dysplasia is a common and controversial skeletal condition that affects many dogs. Any of the large breed dogs (dogs weighing greater than 50 lbs.), and occasionally, a smaller breed dog can have problems with this disease. Commonly affected breeds include the German Shepherd, Labrador Retriever, Rottweiler, and Golden Retriever.
The root of the problem is a deformation of the hip joint. The joint is a “ball and socket” joint. The femur has the ball portion, and the pelvis supplies the socket. Normally, the ball rests very far into the socket (70-80% of the ball is in the socket). In the dysplastic hip, the socket is very shallow which prohibits the ball from resting in the socket properly (i.e., less than 50% of the ball rests in the socket). This produces an unstable joint. When the joint is unstable, it allows the joint to sub-luxate (almost become dislocated) many times over the course of a day. This instability produces the arthritis associated with hip dysplasia.
Hip dysplasia has been recognized as a disease entity for a long time. The exact cause is a major issue of debate. There are definitely genetic and environmental components involved in the cause of this disease.
Genetically speaking, dogs with bad hips are more likely to have puppies that will have bad hips. The Orthopedic Foundation for Animals (OFA) is a registry system for adult dogs (greater than 2yrs old) to assess the conformation of the hip joints. Parents that are OFA certified are less-likely to have puppies with dysplastic hips, but they can not guarantee puppies with normal hip joints
Because parents that have good hips can still result in puppies with bad hips, there must be environmental factors that contribute to hip dysplasia. These environmental factors may include improper mineral balance in the diet of puppies, extra-ordinary stress on the joints during key growing phases, and growing too fast. In theory, if growth of the skeletal system is faster than growth of the muscular system, the result will be an unstable joint. This is similar to constructing a building without an adequate foundation, where the muscular foundation is not developed enough to provide stabilization of the bony structures.
For more information on hip dysplasia prevention and treatment, feel free to contact us.