Illusion Japanese Chin Information Luxating Patellas

What is a luxating patella?

The patella, or knee cap, should be located in the center of the knee joint. The term "luxating" means out of
place or dislocated. Therefore, a luxating patella is a knee cap that moves out of its normal location.

What causes this to occur?

The muscles of the thigh attach directly or indirectly to the top of the knee cap. There is a ligament, called
the patellar ligament, which runs from the bottom of the knee cap to a point on the tibia (shin bone) just
below the knee joint. When the thigh muscles contract, the force is transmitted through the patella and
through the patellar ligament and results in extension (straightening) of the knee joint. The patella stays in
the center of the leg because the point of attachment of the patellar ligament is on the midline and because
the patella slides in a groove on the lower end of the femur (the thigh bone).

The patella luxates because the point of attachment of the patellar ligament is not on the midline of the tibia.
It is almost always located too far medial (toward the middle of the body). As the thigh muscles contract,
the force is pulled against the groove on the inner side of the femur. After several months or years of this
abnormal movement, the inner side of the groove wears down and the patella is free to move out of the
groove or dislocate. When this occurs, the dog has difficulty bearing weight on the leg. It may learn how to
kick the leg and snap the patella back into its normal location. However, because the side of the groove is
gone, it dislocates again easily.

Does a luxating patella cause any long-term problems for my dog?

Some Japanese Chin can tolerate this problem for many years, some for all of their lives. Since the joint
surfaces are very slick and bathed in a slippery joint fluid, there is usually little or no discomfort early in the
process. However, this abnormality predisposes the knee to other injuries, especially torn cruciate ligaments.
Also, with advancing age, the joint may become arthritic and painful. The bones may actually curve in
response to the abnormal location of the kneecap..

Diagnosis

This condition only affects the rear legs. Some of the things you may notice are: back toes pointed in, dog
sometimes carries one of the back legs, or occasionally does a skip-hop on one of the back legs, difficulty
straightening the knee, back legs appear bowed or dog walks with a limp. Your vet can palpate your
Japanese Chin patellas without anesthesia and it takes only a minute or two. It usually does not cause the
dog discomfort. Once you know your dog has Luxating Patella, the next vital piece of information is the
grade of abnormality.

Here is a very brief rundown of the grades of luxation:

Grade 1 - Almost normal, and often little or no noticeable gait abnormality. The patella can only be moved
out of place manually with the leg extended. Luxation resolves spontaneously when pressure is removed.

Grade 2 - Patella goes out of place when the joint flexes and generally stays out until pushed back in place
manually or dog can usually put it back into place by straightening the leg. Or the Patella can be forced out
of place. These Japanese Chin usually have a normal gait.

Grade 3 - Patella is luxated most of the time but can be pushed into place with the limb in extension.

Grade 4 - Patella is out of place all of the time and can be pushed back into place manually. This grade is
almost always the result of truama and is uncommon.

Treatment Options

**You will need to make an informed decision about your Japanese Chin's treatment depending on the
grade of luxation and the age and general health of your Japanese Chin. All Japanese Chin with luxating
patellas can benefit from taking the following steps:

Convervative Treatment:

**Watch your Japanese Chin weight. By keeping her at a lean, healthy weight, you are doing much to
lessen the strain on her knee ligaments.
**Be careful of allowing her to exercise on slippery floors. Put down area rugs on smooth floors so she can
have a good grip and not fear having one of her back legs slip.
**Never encourage begging tricks or jumping.
**Don't allow her to jump down off of things. If you allow your Japanese Chin on the couch or bed, put in
an intermediate "step" of a low footstool and teach her to always go up and down this way.

Most Japanese Chin with this condition will learn to limit their activities by themselves. But some of the
young boisterous ones will need to be taught what behavior they should not do to prevent further
deterioration.

Surgery

Surgery should only be performed if your Japanese Chin has a persistent lameness or if other knee injuries
occur secondary to the luxation. If the Japanese Chin shows no symptoms of pain and is only limping
intermittently, surgery is usually not recommended. This can also depend on the age of the dog. There are
different corrective surgeries out now depending on the degree of luxation. The traditional corrective
surgery involves (usually done on Grades 3 & 4) deepening the groove in the femur and/or realigning the
tendon. The surgery itself will often cause arthritis to set in and the recovery time is long, involving weeks
of crate rest for the Japanese Chin followed up by physical therapy. There are new surgeries being done that
are highly successful in treating Grade 2-3 luxation in younger Japanese Chin. They are a lot less invasive
than the traditional surgery and the Japanese Chin is usually walking within a day or two with weeks of
home physical therapy.

The methods used for surgical repair depend on how far the process has gone before intervention. Surgical
repair may include any or all of the following:
**1) The point of attachment of the patellar ligament is cut from the tibia and transplanted to its proper
location to correct the in correct alignment.
**2) The groove in the femur is deepened so the patella will stay in place.
**3) The capsule around the joint is tightened. This last step is important because the joint capsule will have
stretched during the period of luxation.

If the surgery is performed before arthritis occurs, the prognosis is excellent. Your Japanese Chin should
regain full use of its leg. However, if arthritis has already occurred, the joint will still be somewhat painful,
especially in cold weather