Commonly found in small and toy breed pets, patellar luxation may also affect large breed pets.

I have a 1 year old Chihuahua that has been diagnosed with a patellar luxation. What is this and what can be done about it?

Patellar luxations are commonly found in small and toy breed pets although this condition may also affect large breed pets as well. This disease occurs in the stifle joint (knee joint) where the knee cap no longer glides in the normal groove of the femur, the upper bone of the knee joint. As a result the knee cap may be displaced from this groove and become luxated to one side or the other. There are two types of luxations that occur; medial and lateral. These terms refer to the direction the patella (knee cap) moves in relation to the body. Medial patellar luxations cause the patella to move toward the inside of the leg, while lateral luxations cause the patella to move towards the outside of the leg. Medial luxations are more frequently observed than lateral luxations.
The most commonly observed sign witnessed by pet owners is intermittent weight bearing lameness, where the pet is reluctant to bear weight on one of the hind limbs. This condition may be the result of trauma but more commonly is caused from congenital and developmental abnormalities. Most patients with this condition have associated musculoskeletal abnormalities that result including bone deformities, joint instability and degenerative joint disease. The severity of the luxation is usually graded on a scale of I to IV. Clinical signs usually worsening with the higher grade luxations.
Diagnosis is made by through a thorough physical examination. X-rays may be needed to detect other musculoskeletal abnormalities and evaluate the severity of damage caused from the luxation.
Treatment depends on the severity of the disease and clinical symptoms. Medical or conservative management can be attempted in less severe cases of luxations. Medications such as anti-inflammatories, chondroprotective agents (medications for joint mobility), pain medications and exercise restriction (Rest). In more severe cases, surgery may be required to correct the underlying defect that is causing the luxation to occur. There are many surgical techniques that are used to correct this condition which are determined from the severity of disease present.
Because other diseases may cause similar clinical signs it is important that a Veterinarian examine the pet to help eliminate this condition as the cause. If you believe your pet may be suffering from this condition, please see your veterinarian.