Patellar Luxation in Dogs: Causes, Diagnosis & Treatment

Patellar luxation, also known as luxating patella, is a common condition affecting a dog's knee, specifically the hind limbs. It can cause pain and impact your dog’s mobility, often appearing early in life, typically before six months old. Though it can affect any breed, certain small and toy breeds are particularly prone to this disorder. Early recognition and responsible care help manage this condition and improve your dog’s quality of life.

Understanding Patellar Luxation

Patellar luxation occurs when the kneecap (patella) slips out of its normal position within the femoral groove. Normally, the patella is held securely by the ridges of the femur, allowing smooth movement of the knee. In dogs with shallow or malformed grooves, the kneecap may dislocate either intermittently or permanently, leading to discomfort and mobility issues.

Luxation can be medial (towards the inside of the leg) or lateral (towards the outside), with medial luxation being more common in small breeds. This condition is sometimes called "floating kneecap syndrome" because the patella can feel loose or unstable.

Breeds Prone to Patellar Luxation

While any dog can develop patellar luxation, it is particularly prevalent in small and toy breeds. This includes but is not limited to:

• The English Bulldog
• The Cairn Terrier
• The Labrador Retriever
• The Jack Russell
• The Maltese Terrier
• The Yorkshire Terrier
• Toy and Miniature Poodles (Toy Poodle, Miniature Poodle)
• The Boston Terrier
• The Chihuahua
• The Pomeranian
• The Pekingese
• The Papillon
• The Cavalier King Charles Spaniel

Causes and Risk Factors

Patellar luxation in dogs is generally considered a congenital and inherited skeletal defect where the alignment of the leg bones leads to instability in the knee joint. Environmental factors such as trauma or injury to the knee can also contribute. Maintaining a healthy weight is vital, as obesity increases stress on joints and can worsen symptoms or trigger luxation in predisposed dogs.

Recognising the Severity: Grading Patellar Luxation

Veterinary specialists grade patellar luxation on a scale from 1 to 4 based on the frequency and permanence of the kneecap dislocation:

• Grade I: The kneecap can be manually moved out of place but returns to normal by itself, often with no lameness.
• Grade II: The kneecap occasionally slips out on its own and needs manual reduction or movement of the joint to re-align.
• Grade III: The kneecap is usually dislocated but can be temporarily pushed back into place.
• Grade IV: The kneecap is permanently dislocated and cannot be repositioned manually, often causing significant pain and lameness.

Diagnosing Patellar Luxation

Your vet will perform a physical examination to feel the kneecap and assess its stability. They will enquire about the frequency of limping or signs of discomfort you've noticed. Diagnostic imaging such as X-rays may be used to evaluate the structure of the knee, detect deformities, and plan treatments effectively. Early diagnosis is key to preventing progression and joint damage.

Treatment Options and Management

The management of patellar luxation depends on its severity:

• Mild cases (Grade I): Monitoring the condition may suffice. Your vet may recommend weight management, joint supplements, and physiotherapy to strengthen muscles supporting the knee.
• Moderate to severe cases (Grades II-IV): Surgery is typically recommended to realign the kneecap and correct underlying anatomical issues. Surgical techniques vary but aim to deepen the femoral groove, realign tendons, and stabilise the patella.

Post-surgery, proper rehabilitation including controlled exercise and physiotherapy helps optimise recovery. Home modifications like ramps or steps can ease movement. Always consult your vet for tailored advice and avoid unnecessary strain on affected joints.

Promoting Responsible Ownership

If you are considering getting one of the breeds prone to patellar luxation, look for reputable breeders who screen for genetic conditions to reduce the risk. Early veterinary check-ups and maintaining your dog's ideal weight are crucial to managing health.

When to See a Vet

If your dog shows repeated limping, hesitation to jump or climb, skipping on a hind leg, or obvious pain in the back legs, seek veterinary advice promptly. Early intervention can improve outcomes and prevent further joint damage.

Summary

Patellar luxation is a dislocation of the kneecap affecting mainly small and toy breed dogs, causing a range of symptoms from mild skipping to severe lameness and arthritis if untreated. It is often inherited but can be worsened by obesity or trauma. Early diagnosis, appropriate treatment, and ongoing management are essential to keep your dog comfortable and active.