Patellar luxation, also known as a dislocated kneecap, is one of the more prevalent orthopedic conditions dogs face today. Patellar luxation occurs when the patella (kneecap) no longer stays in place, but instead shifts either towards the inner or outer knee, which can worsen if left untreated. It mostly affects smaller breeds like Terriers and Pomeranians, but there has been a rise in this condition in larger breeds as well. Trauma and genetics are the most common causes of patellar luxation.
Some smaller dogs can have a patellar luxation and not suffer from any pain or other symptoms. A more severe luxation, such as Grade 3 or 4, may need surgery in order to reduce pain and repair any damage in order to increase the function of the leg.