A luxating patella, sometimes referred to as a "slipping kneecap", is an orthopaedic condition that can affect dogs of many breeds, including the Cavalier King Charles Spaniel.

While many Cavaliers with a mild luxating patella continue to lead active, comfortable lives, more severe cases can cause pain, reduced mobility and arthritis over time. Because luxating patella has an inherited component, patella assessment is often included as part of a comprehensive health testing programme for breeding dogs.

This guide explains what a luxating patella is, how it is diagnosed, available treatment options and why screening is important for the long-term health of the breed.

What Is a Luxating Patella?

The patella is the kneecap. Under normal circumstances, it glides smoothly within a groove at the end of the femur (thigh bone) as your dog walks, runs and jumps. A luxating patella occurs when the kneecap slips out of this groove, either occasionally or permanently.

The kneecap may move:

• Towards the inside of the leg (medial luxation), which is the most common form in small breeds.

• Towards the outside of the leg (lateral luxation), which is less common.

The severity varies from dogs that show no obvious signs to those with significant lameness.

What Causes a Luxating Patella?

Several factors can contribute to the condition, including:

• An inherited predisposition.

• Abnormal limb alignment.

• A shallow groove that normally holds the kneecap in place.

• Differences in bone or muscle development.

• Injury or trauma (less commonly).

Because inherited factors are involved, responsible breeders include patella examinations as part of their overall health screening programme.

Signs and Symptoms

Some Cavaliers with a mild luxating patella may never show noticeable symptoms.

Others may experience:

• Intermittent limping.

• Skipping or hopping on one hind leg.

• Suddenly carrying one back leg for a few steps before walking normally again.

• Difficulty jumping onto furniture.

• Reluctance to climb stairs.

• Stiffness after exercise.

• Reduced willingness to play.

• Pain in more advanced cases.

These episodes may become more frequent as the condition progresses.

How Is a Luxating Patella Diagnosed?

Diagnosis usually begins with a physical examination.

Your veterinarian will:

• Observe your dog's gait.

• Examine the knee joint.

• Assess whether the kneecap moves out of position.

• Determine the severity of the luxation.

In some cases, X-rays or advanced imaging may be recommended to assess joint alignment, arthritis or surgical planning.

Understanding Patella Grades

Veterinarians commonly classify luxating patella into four grades.

Grade I

The kneecap can be manually moved out of place during examination but returns to its normal position immediately. Most dogs show few or no clinical signs.

Grade II

The kneecap moves out of position more easily and may remain displaced briefly before returning. Dogs often show intermittent skipping or hopping.

Grade III

The kneecap remains out of position most of the time but can be manually returned to the groove. Lameness is usually more noticeable.

Grade IV

The kneecap remains permanently displaced and cannot be returned to its normal position manually. This is the most severe grade and is often associated with significant limb deformity and reduced mobility.

Treatment Options

Treatment depends on the severity of the condition, your dog's age and the impact on their quality of life.

Conservative Management

Dogs with mild luxating patella may be managed with:

• Maintaining a healthy body weight.

• Appropriate exercise.

• Muscle strengthening.

• Pain relief when required.

• Regular veterinary monitoring.

Many dogs with Grade I or mild Grade II luxation remain comfortable without surgery.

Surgical Treatment

Surgery may be recommended when:

• Lameness is persistent.

• Pain affects quality of life.

• The kneecap frequently dislocates.

• Arthritis is progressing.

• Conservative management is no longer effective.

The surgical technique depends on the individual dog's anatomy and may involve deepening the groove that holds the kneecap, adjusting the attachment of the patellar tendon or correcting bone alignment. Most dogs recover well following surgery when appropriate rehabilitation is provided.

Long-Term Outlook

The prognosis depends on the severity of the luxation and whether arthritis has already developed.

With appropriate management:

• Many dogs remain active and comfortable for life.

• Surgery often produces excellent outcomes in suitable candidates.

• Maintaining an ideal body weight helps reduce stress on the joints.

• Early intervention may improve long-term mobility.

Regular veterinary reviews remain important.

Patella Screening and Responsible Breeding

Because luxating patella has an inherited component, many responsible breeders include patella examinations before breeding.

Screening helps breeders:

• Identify affected dogs.

• Make informed breeding decisions.

• Reduce the frequency of inherited orthopaedic disease.

• Improve the long-term health of future generations.

Patella assessment should be considered alongside other health tests, including cardiac examinations, MRI screening, DNA testing and eye examinations.

Can Luxating Patella Be Prevented?

Not completely.

However, responsible breeding practices can reduce the risk over time by selecting breeding dogs with healthy joints and comprehensive health screening. Maintaining a healthy body weight and providing appropriate exercise throughout life also supports joint health.

Frequently Asked Questions

Is a luxating patella painful?

Some dogs experience little or no discomfort, while others develop pain, particularly if the kneecap frequently dislocates or arthritis develops.

Can a dog live a normal life with a luxating patella?

Yes. Many dogs with mild luxating patella live full, active lives with little or no treatment. More severe cases may require surgery to restore comfort and mobility.

Does every dog with a luxating patella need surgery?

No. Treatment depends on the severity of the condition and your dog's clinical signs. Mild cases are often managed conservatively.

How is a luxating patella diagnosed?

Diagnosis is usually made during a veterinary orthopaedic examination. Imaging studies may be recommended for surgical planning or to assess associated joint changes.

Should breeding Cavaliers have patella examinations?

Yes. Patella assessment is an important component of a comprehensive health testing programme and supports responsible breeding decisions.

In Conclusion…

• A luxating patella is a kneecap that slips out of its normal position.

• Mild cases may cause few or no symptoms.

• More severe cases can result in pain, lameness and arthritis.

• Veterinary examination is required for diagnosis and grading.

• Treatment ranges from conservative management to surgery.

• Patella screening is an important part of responsible breeding.

Disclaimer

The information provided in the Cavalier Knowledge Centre is intended for general educational purposes only and is not a substitute for veterinary advice, diagnosis or treatment.