Feline Hip Dysplasia
When you hear people talk about Hip Dysplasia and that radiographs have been taken most people are referring to dogs. But this problem also applies to cats in general. Hip Dysplasia is a hereditary defect in the socket joint (in the pelvis) which means that it is not as deep as it normally should be. Because of this the ball does not fit exactly in the socket joint and the surfaces begin to rub against each other, causing the cartilage to degenerate. Then the joint surface is made up solely of bone (the cartilage having been worn away) leaving a bone-against-bone joint surface which is painful for the cat. The problem is that the body cannot renew the cartilage, and the body tries to repair the damage by increasing bone production which only serves to make the problem worse. Cats in general are very good at not showing pain and can suffer from HD without limping at all. Instead they may move more carefully or less than cats normally do, and may also avoid jumping. Cats with a mild degree of HD may not suffer at all.
Many scientist believe that many of the changes in the hip joint are directly related to laxity or looseness in the hip joint, and that the key factor may be the genetic component that produces the laxity or looseness.
Clinical Signs:
The first clinical signs associated with hip dysplasia may be very subtle. The immature cat may have an occasional limp in the affected rear limb. There may be difficulty rising from a sitting position, reluctance to jump, or the appearance the they are "loose" in the rear limbs.
Laxity and malformation of the joint allows the joint to sub-luxate, which is a partial dislocation. It is this sub-luxation that eventually causes the problems associated with hip dysplasia.
If both hips are dysplastic there may be no noticeable lameness. At this point there may be little to no degenerative joint disease (DJD) also known as arthritis.
The other presentation occurs later in life and there will usually be a definite lameness. The lameness can be in one hip or both. By this point DJD or arthritic changes have usually began due to the chronic or continuous sub-luxation.
Hip laxity can be detected on physical exam by performing a maneuver that produces a sign called the "Ortolani sign". The Ortolani sign tests for the sub-luxation that is characteristic of hip dysplasia. An Ortolani sign should not be considered negative until it has been performed with the cat under sedation.
A positive Ortolani sign indicates that there is laxity in the hip and that hip is either already dysplastic or has a high chance of becoming dysplastic in the future. This means a radiograph is in order.
Katzen tests for FHD by the Pennhip method. We will not breed with any cat with a ‘borderline’ or lower.
The grading protocol under this system is as follows:
Good: good hips, no anomalies
Borderline: not quite perfect structure, but not pronounced dysplastic
Grade 1: the mildest form of dysplasia
Grade 2: moderately affected hips
Grade 3: badly affected hips
This information does not replace Veterinary advice nor care. If in question please see your Veterinarian.
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