What Is Hip Dysplasia in Dogs?

The word "dysplasia" means abnormal growth or structure. If your dog has canine hip dysplasia, the leg bone and pelvic (hip) bone don't fit like a ball into a catcher's mitt because the cup formed by the pelvic bone is too shallow. The leg bone slides out of the pelvic socket and may dislocate. Painful arthritis can develop in your dog. Dysplasia can occur in one or both of your dog's hips. Dysplastic hips are one type of degenerative joint disease (DJD) in dogs.

Key facts about hip dysplasia in dogs

• Canine hip dysplasia is a form of arthritis.
• Overfeeding makes hip dysplasia worse.
• Using joint supplements early in your dog's life can decrease the severity of hip dysplasia.
• Once your dog has hip dysplasia, he or she should swim rather than run.

Which dogs are most at risk for hip dysplasia?
Large breed dogs are prone to hip dysplasia, including St. Bernards, German Shepherds, Labrador Retrievers, Golden Retrievers, and Rottweilers. Genes, nutrition, and environment contribute to the development of canine hip dysplasia.

Anatomy of the hip and hip arthritis
The hip, or coxofemoral joint (from coax for hip and femoral for the femur thigh bone), is where the spine and upper body meet the leg. Three bones fuse together to make the hip bone: the sacrum, which embraces the lower spine; the ilium which forms the portion we sit on; and the acetabulum, which forms the sides. The acetabulum has a deep groove like a catcher's mitt into which the top of the large thigh bone, the femur, sits. This is a ball and socket joint, and the head of the femur rotates like a ball within the hip (acetabular) socket. The femur is held in the socket by hip muscles and by the round ligament that directly attaches the femur to the acetabulum. The bones are covered with cartilage, bathed with synovial fluid, and sealed inside a synovial membrane. The cartilage and synovial fluid work to cushion movement so that the bones don't jar together when your dog runs or jumps.

Effect of hip dysplasia on dogs
Canine hip dysplasia is a problem for dogs and their owners because it causes severe pain and immobility. If your dog has hip dysplasia, he or she will struggle to get up, to climb stairs, to get into a car, and to squat to urinate and defecate. Many dogs lose their good natures because of immobility and pain. The relationship you have with your dog deteriorates because your dog won't feel like playing, and it becomes an effort to do anything with your dog since he or she needs to be lifted and carried.

Genetic predisposition to hip dysplasia
There are over 400 dog genetic diseases, and canine hip dysplasia is one of the most significant. It is a polygenetic disease, meaning more than one gene is involved. Some breeders certify their dogs have good genetics by submitting X-rays to the Orthopedic Foundation for Animals (OFA) or to the University of Pennsylvania Hip Improvement Plan (Penn HIP). Dogs certified as good or excellent by OFA or Penn HIP are less likely to produce puppies carrying genes for hip dysplasia.

3 tips to prevent hip dysplasia in dogs
1. Stop breeding dogs that have hip dysplasia: Efforts to stop breeding dogs with hip dysplasia have benefited several breeds. In German Shepherds, for example, after five years of selection the incidence of hip dysplasia decreased from 55% to 24%. In Labrador Retrievers, the incidence decreased from 30% to 10%. These efforts have meant that fewer families will have the painful chore of caring for their beloved dog that aches so much her or she can hardly walk.
2. Avoid overfeeding your dog: Diet has a profound effect on hip dysplasia. In fact, diet is so important that major dog food manufacturers now market diets specifically for large-breed puppies most prone to develop dysplasia. These diets have fewer calories because research has proven that the less these puppies weigh, the less likely they are to develop dysplasia. Puppies fed 25% less than their littermates had markedly less hip dysplasia as adults; and those pups that eventually developed dysplasia did so at a later age. Thinner pups had more pain-free years than the chubby pups. Keeping your pet's weight on the light side so that the ribs can be felt helps prevent your dog from developing dysplasia, and helps him or her move more easily if it does develop.
3. Exercise young dogs with moderation: Puppies can be predisposed to develop joint disease if they are asked to do more than they should, such as jumping high or running long distances. Don't have your puppy jump higher than his or her elbow until he or she is at least one year of age. If your puppy jumps on his or her own, do not panic, but do not encourage it either. Design training and agility equipment so that bars are at the level of the elbow until your puppy has adult bone and muscle structure. Because hip dysplasia develops in puppies, protecting them while they're young makes sense. Swimming is one of the best exercises for dogs because it builds muscles without stressing joints.

Do cats get hip dysplasia?
Cats don't develop hip dysplasia very often, but they frequently develop joint problems. The most common locations for joint problems in cats are the elbows and ankles.