PATELLA LUXATION: Patella Luxation is one of the most common orthopaedic condition in dogs. It is a condition that allows one (or both) kneecaps to easily displace out of their normal position.
Sometimes referred to as "small dog syndrome" it affects a variety of breeds, Yorkies, Chihuahua, Pomeranian, Miniature Poodles and the Japanese Spitz, the incidence in larger breeds has been on the rise over the last ten years.
The patella, or kneecap is a small bone buried in the tendon of the extensor muscles (these are the quadriceps muscles) of the thigh. The patella normally rides in the groove within the femur (thigh bone) in the knee.
The patellar tendon attaches on the tibial crest, which is a bony prominence located on the tibia (shin bone) just below the knee. The quadriceps muscle, the patella and its tendon form the "extensor mechanism" and are normally well- aligned with each other.
Patella Luxation (dislocation) is a condition where the knee cap rides outside the trochlean groove when the knee is flexed. It can be further characterised as medial or lateral depending on whether the knee cap rides on the inner or outer aspect of the stifle respectively.
Signs and Symptoms
SIGNS & SYMPTOMS: Symptoms associated with Patella Luxation vary greatly with the severity of the disease. Most dogs affected by this disease will suddenly carry the limb up for a few steps (skip) and may be seen shaking or extending the leg prior to regaining its full use.
Patella Luxation can affect both knees resulting in loss of function.
Over time the knee cap may luxate more and more often out of its groove, eventually exposing areas of bone which can then lead to arthritis and the associated pain.
ORIGINS: Patella Luxation can occur from traumatic injury to the knee, and there is some evidence to suggest that it can also be hereditary. Affected dogs can appear normal at birth but should they carry the gene defect then the problem can arise later in the dogs development.
PROGNOSIS: In mild or moderately affected animals prognosis following orthopaedic or soft tissue surgery is often good.
BREEDING: If you are a serious breeder or a conscientious occasional breeder, it is wise to have your dogs graded and to reflect on the suitability of using any affected dogs in your breeding programme.