Patellar luxation is a prevalent orthopedic condition in dogs, characterized by the dislocation of the patella (kneecap) from its normal position in the femoral groove. This condition is classified into two primary types: Medial Patellar Luxation (MPL) and Lateral Patellar Luxation (LPL).Veterinary Digital X-ray imaging diagnosis can clearly understand the severity of dislocation, misalignment, deformation, arthritis, etc.

Medial Patellar Luxation (MPL):
MPL is most commonly observed in small and toy breeds, such as Pomeranians, Chihuahuas, and Yorkshire Terriers. It is typically associated with genu varum, a condition where the limbs display a bow-legged appearance. In MPL, the quadriceps muscle group exerts a medial pull on the patella, which, combined with the inward angulation of the distal femur and proximal tibia, predisposes the patella to dislocate medially. Chronic MPL can lead to degenerative joint disease and significant alterations in limb conformation.

Lateral Patellar Luxation (LPL):
LPL, while less common, is more frequently seen in larger breeds like the Labrador Retriever, Saint Bernard, and Great Dane. It is often associated with genu valgum, a condition where the limbs exhibit a knock-kneed appearance. In LPL, the lateral pull of the quadriceps and the outward angulation of the femur and tibia contribute to the lateral displacement of the patella. This condition can also be seen in small breeds as a late-stage complication of chronic MPL, where progression leads to bidirectional instability.

Pathophysiology and Clinical Implications:
Both MPL and LPL are the result of complex interactions between genetics, abnormal limb development, and muscle imbalances. The severity of the condition is graded from I to IV, with higher grades indicating more severe and persistent luxations. Clinically, affected dogs may exhibit lameness, gait abnormalities, or even intermittent skipping during locomotion.

The relationship between patellar luxation and genu deformities is crucial for both diagnosis and treatment. Surgical interventions, such as tibial tuberosity transposition, trochleoplasty, and corrective osteotomies, often target the underlying anatomical deviations that contribute to the luxation. Early detection and appropriate intervention are essential to prevent long-term complications, such as osteoarthritis and chronic pain.