Patellar luxation

Patellar luxation is a genetically predisposed condition in which the dog's kneecap does not stay in its normal position. Dogs do not usually develop this at birth but it occurs as a result of misaligned growth of the femur and/or tibia during the first year of life. This condition can gradually worsen over the course of the dog's life.

The displacement of the kneecap can occur either towards the inside or outside of the knee joint. In small dog breeds, displacement towards the inside is most common.

There are different degrees of patellar luxation depending on whether the kneecap is periodically or permanently out of joint:

1. Grade 1: The patella may dislocate when the leg is extended but slides back into place immediately.
2. Grade 2: The patella detaches spontaneously when the joint is flexed and remains out of joint until it is manually repositioned after the joint is stretched.
3. Grade 3: The patella is permanently dislocated. It can be put back into place when the leg is extended but falls out again when bent.
4. Grade 4: The patella is permanently out of joint and cannot be put back into place.

NKK uses a scale of 0–3 to classify the degree of patellar luxation.

Prolonged inward and outward movement of the kneecap leads to discomfort or pain, cartilage destruction and early calcification in the knee. The condition can worsen over time if left untreated.

Symptoms of patellar luxation

The symptoms of patellar luxation can vary depending on the severity of the condition, but common signs include limping, a hopping gait, signs of pain such as panting or whining, and a decreased activity level. However, it is important to note that not all dogs will show symptoms, especially in cases of less severe patellar luxation. Therefore, regular veterinary check-ups are important to detect the condition early and prevent further complications.

When should you operate?

When it comes to treating patellar luxation, surgery may be necessary in cases where symptoms are severe or recurrent. This can be determined by several factors including the degree of patellar luxation, additional complications such as joint or tendon damage, the age and size of the dog, and the effectiveness of conservative treatment methods. In general, younger and smaller dogs often have better outcomes after surgery.

The vet will carefully consider all of these factors and discuss the treatment options with the owner to make the best decision for the dog's well-being. Early intervention and treatment is important to minimize the risk of long-term complications and improve the dog's quality of life.

Over 90% of dogs become completely limp-free after surgery.

Patella status

For the following dog breeds, the Norwegian Kennel Club has introduced requirements for documented patellar status when registering puppies:

• Affenpinscher (from March 1, 2021).
• Bichon Havanais (from 1 April 2016).
• Boston terrier (from 1 January 2023).
• Chihuahua short-haired and chihuahua long-haired (from 1 January 2016).
• Miniature Pinscher (from 1 April 2019).
• English Bulldog (from 1 July 2017).
• French Bulldog (from 1 July 2017).
• Griffon belge (from 1 March 2021).
• Griffon bruxellois (from 1 March 2021).
• Jack Russell Terrier (from January 1, 2019).
• Japanese chin (from 1 March 2021).
• King Charles Spaniel (from March 1, 2021).
• Kleinspitz (from 1 March 2021).
• Xoloitzcuintle (Mexican Hairless Dog), small and medium variety (from March 1, 2021).
• Mittelspitz (from 1 March 2021).
• Pug (from January 1, 2020).
• Papillon (from March 1, 2021).
• Petit brabancon (from 1 March 2021).
• Phalene (from March 1, 2021).
• Prague Rat (from March 1, 2021).
• Russian tsvetnaya bolonka (from January 1, 2017).
• Yorkshire Terrier (from August 1, 2021).

The examination must be performed by a veterinarian with an agreement with NKK when the dog is at least 12 months old and the result must be registered on DogWeb.

When using foreign dogs, a copy of the dog's patella certificate must be included with the registration application. The result of this certificate will be entered into DogWeb for countries that have identical examination routines to Norway, such as Sweden. For other countries, the result cannot be entered into DogWeb but can still be used as "known patella status" for registration of puppies.

Exemption for the use of foreign dogs can be applied for. A reasoned application must be submitted to the NKK after the breed club's approval before a decision is made. General exemption is granted for the use of frozen semen that was frozen before the restrictions came into effect and where the dog is no longer alive.

More information can be found at NKK's websites.

Please contact us if you have any questions about the disorder or to schedule an appointment for a preliminary examination or surgery.