Dog Owner's Home Veterinary Handbook.pdf - Mr. Walnuts

398 •DOG OWNER’S HOME VETERINARY HANDBOOK
Luxating patella is usually an inherited developmental defect. Rarely, it is
acquired through trauma.
Medial luxation is more common. It occurs in toy, miniature, and large
breeds, and is apparent in some puppies when they begin to walk. In others it
appears later. The patella may slip in and out of place, resulting in a gait that
is sometimes normal and sometimes not. When the patella is out of place, the
affected leg is usually carried with the stifle joint bent and the foot turned
inward. The condition is bilateral in about 25 percent of cases.
Lateral luxation occurs in large and giant breeds at 5 to 6 months of age. A
knock-kneed stance is the most noticeable sign. The foot often twists outward
as weight is placed on the limb. Both knees are almost always involved.
In the early stages, luxating patella may not be painful. But pain can
increase as the grooves are polished smoother by the slipping action of the
kneecap and as arthritis develops in the joint.
The diagnosis of luxation is made by attempting to push the patella out of
the trochlear groove. The degree of luxation is graded 1 to 4, depending on
how easy it is to dislocate the patella and whether the patella returns spontaneously
to the trochlear groove. This manipulation should only be done by
breeders or veterinarians experienced in this technique. Preliminary veterinary
screening for medial patella luxation should be done on dogs of toy and small
breeds at 6 to 8 weeks of age, before these pups are sent to their new homes.
Treatment: A Grade 1 luxation may never worsen, and these dogs may
need only medical treatment to deal with any pain that develops. For other
dogs, though, surgery to deepen the trochlear groove and repair any loose or
torn ligaments is usually recommended. The specific operation depends on
the age of the dog and the type of luxation.
The OFA maintains a patellar luxation registry and issues certificates to all
dogs who palpate normal at 12 months of age or older. The GDC maintains a
medial patella luxation registry for breeds in the Terrier Group and also issues
certificates to dogs who palpate normal at 12 months of age or older. The
GDC is attempting to accumulate information on patella luxation based on
palpating patellas when dogs are X-rayed for hip dysplasia. This GDC registry
is now merged with OFA.
Dogs with genetically determined patella luxation should not be bred.
ELBOW DYSPLASIA
Elbow dysplasia is a common cause of front-leg lameness in large-breed
dogs. Breeds predisposed to elbow dysplasia include the Golden Retriever,
Labrador Retriever, English Setter, English Springer Spaniel, Rottweiler,
German Shepherd, Bernese Mountain Dog, Chow Chow, Chinese Shar-Pei,
Newfoundland, and others.