Patellar luxation in dogs: symptoms and how to help

Patella dislocation in dogs is an orthopedic condition in which the patella — a small bone of the knee joint, also known as the kneecap — moves from its normal position and causes instability throughout the region. The problem can affect dogs of different sizes, but it is more frequent in small breeds, according to a study published by the Federal University of Rio Grande do Sul. The condition can be of genetic or traumatic origin and requires caregivers’ attention to ensure the animal’s welfare.

What is Patella Luxation?

Dislocation occurs when a bone moves partially or completely within a joint, leaving its usual anatomical position. In the knee, this change involves the patella, also called the kneecap. The patella has an important role in the movement of the knee, as it functions as a kind of pulley for the muscles responsible for the extension of the joint. During this movement, it slides through the trochlear groove, a depression located in the femur.

When the dog’s patella leaves the place, it fails to properly follow the movement within that groove, which impairs the pet’s ability to extend the knee, causing symptoms such as lameness and discomfort. The condition can be classified according to the direction of displacement: medial or lateral.

Types of patellar dislocation

The medial patellar dislocation occurs when the patella moves to the inner part of the knee or to the other posterior limb. It represents about 75 to 80% of cases involving the region and is more common in dogs of mini and small breeds, according to Alieve and Marcelo Meller (2018).

The lateral patellar dislocation occurs when the patella moves to the outside of the knee or to the opposite side of the other limb, presenting a greater occurrence in large dogs, according to Hulse (1981) and Alam et al. (2007).

The dislocation of the patella can affect one or both of the dogs’ knees. When only one joint is affected, the frame is called a unilateral dislocation. When both knees present the alteration, the picture is classified as bilateral dislocation. In both cases, the dog with dislocation feels a lot of pain and needs to receive veterinary help as soon as possible.

Causes of Patella Luxation

Patella luxation in dogs can arise for different reasons. Usually, the condition is congenital and ends up being triggered by hereditary factors. This means that the dog is born with some anatomical alteration that favors displacement or predisposes it. Some animals may also develop patella dislocation from traumatic origin, through fractures or impacts in accidents or falls.

Congenital patellar dislocations are related to anatomical deformities that cause a misalignment in the patella region. Although dislocation is not always present at the time the dog is born, the changes that will be responsible for it accompany the animal from birth.

According to Denny (2006), patients with congenital patella dislocation usually have bone deformities and musculoskeletal abnormalities, such as alteration of the angle of inclination (staff thigh), lateral rotation and curvature of the distal femur, shallow trochlear groove with the medial trochlear crest and lateral rotation and looseness of the femoro-tibial joint.

Symptoms and clinical signs

In the early grades, some dogs with patellar dislocation may not show any noticeable clinical signs of the condition. In more advanced stages, however, displacement can provoke symptoms such as lameness (missing), paw stiffness, difficulty moving and reduction in physical activity, as well as pain, irritability and apathy. These signals may vary in intensity depending on the severity and frequency of the displacement.

It is important to observe the behavior of the animal, as the pain can lead to changes in habit, such as avoiding climbing stairs or jumping. If the guardian notices any change in the gait or behavior of the dog, he or she should seek a vet for evaluation.

Treatment and care

The treatment of patella dislocation depends on the severity of the alteration. More conservative approaches include the use of medications and physiotherapy, but in some cases surgical procedures are indicated to correct the positioning of the kneecap. The choice of treatment should be made by a professional, considering the degree of dislocation, the age of the animal and the presence of other conditions.

Without proper care, the recurrent displacement of the patella favors joint wear and increases the risk of complications, such as osteoarthritis and chronic pain, impairing the welfare and quality of life of the animal. Therefore, early diagnosis and veterinary follow-up are essential to prevent the progression of the disease.

If you suspect that your dog may be having patella dislocation, do not hesitate to seek professional guidance. The Boca no Trombone Portal will continue to bring information about saúde e bem-estar animal to keep you well informed.

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