Hip Dysplasia in Dogs: Causes, Symptoms, and Tests
Normal hips are rated Excellent, Good, or Fair, depending on how closely they match the ideal. Dysplastic hips are rated Mild, Moderate, or Severe. If the findings are not clear, the hips are rated Borderline.
In a dog with mild hip dysplasia,the X-rays will show mild subluxation (increased space in the joint) with the hip ball partway out of the socket. There are no changes associated with degenerative arthritis.
In a dog with moderate hip dysplasia,the hip ball is barely seated into a shallow acetabulum. Arthritic changes begin to appear. These include wear and flattening of the femoral head, a rough appearance to the joint surfaces, and the beginning of bone spurs.
In a dog with severe hip dysplasia,the head of the femur is completely out of the joint and arthritic changes are marked. Once arthritis is noted, the condition is irreversible. But even with arthritis, some dogs are not lame. The onset of lameness is unpredictable, and some dogs may go most of their lives with dysplastic hips but no lameness. Others develop lameness as puppies.
The OFA maintains a hip dysplasia registry for purebred dogs. An OFA-certified radiologist will review hip X-rays taken by your veterinarian and, if the conformation of the hips is normal for the breed, certify the dog as Excellent, Good, or Fair and assign him an OFA number. As an optional step, you can have the OFA number added to your dog’s AKC registration papers.
Dogs must be 24 months of age or older to be tested. Some female dogs will show subluxation when X-rayed around an estrus cycle, so OFA recommends not X-raying females around a heat period or within three to four weeks of weaning a litter.
The OFA registry is closed. That means if the dog is found to have hip dysplasia, the information remains confidential unless the owner marks off on the application that all results may be made public.