dog kneecap dislocation

It doesn’t take a medical degree to know that body parts should stay in their intended location. Some out-of-line anatomy, such as the knee is more devastating than others. At Oakhurst Veterinary Hospital we see out of place knees, also known as luxating patellas, on the daily.

A pet with a luxating patella is common, and sometimes this finding is no big deal. Other times, though, it can affect a pet’s comfort and ability to move. When a pet is diagnosed with a luxating patella, our veterinarians are equipped to help provide the best and most appropriate care for the situation.

Anatomy of the Knee

The patella, or knee cap, is a common cause of turmoil in the rear leg of the dog (and less commonly, cats). The patella is a small piece of bone that is embedded in a ligament that slides up and down the front of the knee.

Keeping the lower femur and upper tibia in an effective plane to create a smooth hinge-like action, the patella is meant to stay within a vertical groove on the front of the knee.

A luxating patella can occur due to trauma and other injuries, but they are very commonly diagnosed as congenital problems. Changes such as a longer than normal patellar tendon, abnormally formed tibia or femur, hip dysplasia, or even muscle changes in the quadriceps can lead to patellar luxation.

Small breeds such as toy poodles, Yorkies, and Chihuahuas are more prone to luxating patellas, but any breed or size of dog or cat can be affected.


Patellar luxations can be classified as medial (sliding to the inside of the leg) or lateral (sliding outward). They are also graded on a scale of one to four:

Grade 1 –  Patella is easily able to be luxated but returns to position easily and on its own

Grade 2 – The patella luxates in and out of joint on its own frequently, sometimes remaining out of place for periods of time and resulting in eventual joint changes

Grade 3 – The patella is out of place most or all the time, resulting in changes to the function of the limb. It can be put back into place manually, but will not stay.

Grade 4 – The patella is permanently out of place and results in a severe compromise in limb use

Treating the Luxating Patella

Pet owners often notice their pet may have a problem when a sudden rear-limb lameness strikes. Sometimes it seems to resolve quickly on their own as the patella returns to position. In other situations a luxating patella may be diagnosed on a routine wellness examination.

Many pets with patella luxation, particularly grade 1 or 2, do not require extensive treatment. Weight management is helpful to reduce strain on an already compromised joint. Joint support vitamins and supplements may also be recommended to help the abnormal joint and provide extra protection for other joints that may be overloaded as a result of patellar luxation.

When a luxating patella results in pain and/or decreased functionality, a surgical approach may be recommended. There are several ways to help correct a luxating patella, and the patient’s individual situation is taken into account when a recommendation is made. Surgical correction can have a dramatically positive effect on a pet who is severely affected by a luxating patella.

As far as out of place body parts go, a luxated patella is pretty benign. Because it has the potential to impact a pet’s quality of life, however, it should be addressed. If you suspect your pet might have a luxating patella, don’t hesitate to give us a call. Anything we can do to help your pet live a happier life is worthwhile in our book!