Patellar luxation
in dogs

What is a patellar luxation?

The patella, or kneecap, is a small bone at the front of the knee. It normally glides within a natural groove of the femur — the trochlear groove — as the leg bends and straightens.

In some dogs, various anatomical defects cause the patellar mechanism to be poorly aligned. The kneecap can then slip out of its groove and move towards the inside or, more rarely, the outside of the knee.

When the kneecap luxates, the dog feels discomfort or pain that prompts it to lift the leg temporarily. Once the kneecap has returned to place, it often resumes a perfectly normal gait.

It is this alternation between limping and normal walking that often characterises the condition in its early stages.

What are the symptoms?

The clinical signs vary considerably depending on the grade of luxation. Owners frequently report:

• episodes of intermittent lameness;
• a few strides taken on three legs;
• a skipping or hopping gait;
• discomfort that gradually worsens over time;
• reduced physical activity;
• difficulty running or jumping;
• stiffness after rest;
• permanent lameness in the most advanced cases.

Some dogs show very subtle symptoms for several years, while others quickly develop significant discomfort.

Why should this condition be taken seriously?

Even when the symptoms seem mild, patellar luxation should not be regarded as a simple, harmless quirk.

With each luxation, the joint is subjected to abnormal stresses that encourage inflammation, cartilage wear and osteoarthritis.

In some dogs, the gradual progression of the condition can also alter the growth or alignment of the bones of the limb.

Chronic luxation also increases the risk of cranial cruciate ligament rupture, a condition frequently associated with advanced patellar luxation.

How do we diagnose a luxation?

At Colvet, the diagnosis always begins with a full orthopaedic examination. We observe your dog's gait, assess the stability of the knee and determine how easily the kneecap can be moved out of its groove. This examination notably allows us to establish the grade of the luxation.

Radiographs are generally recommended in order to assess the alignment of the limb, look for any associated bony abnormalities and prepare for possible surgery.

As with all our orthopaedic examinations, we adapt our approach to the temperament and comfort of each animal in order to keep stress and discomfort to a minimum.

When should surgery be considered?

Not every patellar luxation necessarily requires immediate surgery. The decision depends in particular on:

• the intensity of the symptoms;
• how often the episodes of lameness occur;
• the grade of the luxation;
• the dog's age;
• how the condition has progressed over time;
• any joint changes already present.

When the luxation causes regular discomfort, encourages the onset of osteoarthritis or risks leading to gradual deterioration of the limb, surgical correction is generally recommended.

What does the surgery involve?

The aim of surgery is to allow the kneecap to regain a stable, natural path within the knee. Depending on the abnormalities present in each patient, several surgical steps may be combined:

• deepening of the trochlear groove;
• realignment of the patellar mechanism;
• adjustment of the soft tissues;
• correction of certain bony deformities where necessary.

Each procedure is planned individually according to the anatomy and the specific needs of your companion. There is no single technique that suits every dog.

What results can be expected?

In the great majority of cases, surgery brings a significant improvement in the comfort and function of the limb. The aim is to:

• eliminate or greatly reduce the episodes of lameness;
• restore a more natural gait;
• slow the onset of osteoarthritis;
• lastingly improve quality of life.

The prognosis is generally excellent when treatment is provided before significant joint damage develops.

Understanding before deciding

At Colvet, we know that surgery always raises many questions. We take the time to explain to you exactly what is happening in your animal's knee, to review the radiographs with you and to discuss the expected benefits as well as any limitations of the treatment.

Our aim is for you to fully understand your companion's condition before making a decision. Because good surgery always begins with an accurate diagnosis and clear information.