Patella Luxation

Description and Cause

This is an inward and outward displacement of the patella (kneecap) with inward luxation the most common. It can be genetic/congenital, developmental or trauma related but usually develops with age. It is most common in little dogs including Pomeranian, Yorkshire Terriers, Chihuahaus and Miniature and Toy Poodles. Patella Luxation has however also been seen in Labradors, Flat Coated Retrievers, Boxers and St Bernard’s.


This condition is usually noticed in dogs less than two years of age. Signs range from mild to severe, which are classified into four grades ranging from intermittent luxation to permanent luxation and include temporary or occasional lameness possibly accompanied by a 'hopping' motion. Eventually the dog may hold the leg permanently off the ground. If both legs are affected, the dog may adopt a crouched gait and posture, appear bow legged and may even walk on the forelegs with the hind legs completely off the ground. There is no joint pain unless secondary Osteoarthritis has developed. In dogs showing long-term symptoms of patella luxation, lameness may develop due to secondary cruciate ligament injury.

Diagnosis is by examination and x-ray.


Mild cases (low grades) can be managed conservatively when lameness is infrequent. This includes Physiotherapy and Hydrotherapy. Pain relief if required.

More severe cases (higher grades) may require surgery and post operative rehabilitation.


Medial Luxating Patella Repair can be performed. There are three steps to the surgery:

  1. The point where the patella ligament is attached is moved and surgically fixed to its proper location.
  2. The groove where the patella sits is deepened so the patella will stay in place.
  3. The capsule around the knee joint is tightened.

It is important to have this surgery performed before arthritis occurs in the joint. If there is no arthritis, the dog should regain full use of its leg. If there is arthritis in the joint already, the joint can still be painful, especially in the cold weather.