Patellar luxation

Patellar luxation in dogs is a condition in which the kneecap (patella) slips out of its fixed position on the thigh bone. This is a common condition among several dog breeds. From August 15, 2013, the Norwegian Kennel Club began registering patella status centrally.

We print patella tests

Only veterinarians who have an agreement with Norwegian Kennel Club to issue patella certificates can perform the examination and register the results in DogWeb. At A-Vet, Elisabeth Bjørnestad is authorized to issue patella certificates.

The owners must bring a completed form from NKK with them when they visit the vet to have certificates issued.

Patellar luxation has a hereditary predisposition and is more common in certain breeds. Dogs are not usually born with the condition, but it develops 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.

The NKK classifies patellar luxation on a scale from grade 0 to grade 3, depending on whether the kneecap is periodically or permanently out of joint:

0. Grade 0: Normal (free from patellar luxation).
1. Grade 1: The patella is in place, but can be manually dislocated. It spontaneously slips back into its normal position.
2. Grade 2: The patella is easily dislocated manually or spontaneously. It is dislocated much of the time, but can be reduced.
3. Grade 3: The patella is permanently luxated and cannot be reduced.

Repetitive inward and outward movement of the kneecap can lead to discomfort or pain, cartilage damage, and the development of osteoarthritis in the knee. The condition can worsen over time.

Symptoms of patellar luxation

Symptoms vary with severity. At grade 1, the dog is often asymptomatic or exhibits only a brief “jumping” gait as the kneecap slips out and back. At grades 2–3, lameness and decreased use of the leg often become more apparent, and some dogs show signs of pain such as whining or reluctance to engage in activity. Because mild patellar luxation may cause few or no visible symptoms, a veterinary examination is important to assess the condition.

When should you operate?

When it comes to treating patellar luxation, surgery may be necessary in cases where symptoms are severe or recurrent. This is assessed based on several factors, including the degree of patellar luxation, additional complications such as joint or tendon damage, the dog's age and size, and the effectiveness of conservative treatment methods.

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.

Studies show that over 90% of dogs have a good to very good result 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 Frize (from 1 July 2025).
• 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).
• Eurasian (from June 1, 2025).
• 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).
• Pomeranian (from July 1, 2025).
• Prague Rat (from March 1, 2021).
• Russian tsvetnaya bolonka (from January 1, 2017).
• Yorkshire Terrier (from August 1, 2021).

This list may change over time — always check NKK's official overview for current requirements.

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 in 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 if the examination was performed in a country with examination routines that correspond to those in Norway, for example 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 website.

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