This is defined as medial or lateral displacement of the patella from its normal anatomic position in the femoral trochlea. Patella luxation may vary from not causing a detectable lameness to being severely disabling. Pets may change from showing no sign of being affected, to needing surgical correction. Anatomic abnormalities may worsen as a pet grows and ages. If not corrected early continued abnormal strains on muscles, bones and tendons can lead to a worsening of the condition and may require more extensive orthopedic surgery to correct for the condition. Correct surgical correction at an early age may fully prevent deterioration of the joint from the condition.
Normal Stifle Patellar Luxation
Most pets with patellar luxation have the problem because of genetic inheritance. Medial patellar luxation is greater then 75% of the luxations, and usually occurs in small to medium sized dog breed and some cats. Larger dogs are less likely to have patellar luxation, but those affected may have medial or lateral luxation and are more likely to be disabled without surgical correction.
This is one of the most common stifle (knee) abnormalities in dogs. It is likely that both knees are affected.
Clinical signs depend on severity. Lameness will also vary with amount of degenerative arthritis, chronicity of disease, and occurrence of other stifle joint abnormalities (e.g., cruciate ligament rupture). As with many joint conditions smaller dogs tend to tolerate the condition more than larger dogs.
You may detect a persistent or intermittent abnormal hind limb carriage and function. Patellar luxation is classified into grades IIV.
Grade Ipatella can be manually luxated; patella reduces when pressure is released
Grade IIpatella can be manually luxated or can spontaneously luxate with flexion of the stifle joint; patella remains luxated until it is manually reduced or the patient extends the joint and derotates the tibia in the opposite direction of luxation.
Grade IIIpatella remains luxated most of the time but can be manually reduced with the stifle joint in extension; flexion and extension of the stifle joint result in reluxation of the patella.
Grade IVpatella is permanently luxated and cannot be manually repositioned.
The medical and surgical recommendation to patellar luxation depends on numerous issues including grading, clinical signs, the pet's age and other health issues.
All pets should be on a nutritional supplement that contains glucosamine and other supplements known to help the joints. We recommend the Vetri-Science line of products, specifically Glycoflex 1, 2 or 3. Pet's should be kept to a lean body weight and/or should be assisted in weight loss if overweight.
Surgery should be considered on all pets that show clinical signs. Corrective surgery has a high rate of success. There is a high rate of degenerative joint disease that may occur if the condition is not treated. The patient will be at risk for worsening of the grade of luxation and for other injuries, particularly for cranial cruciate injury if the condition is not surgically addressed.
Surgery to correct may be as simple in young, mildly affected pets as only a soft tissue corrections called a lateral imbrication. Typical corrections include orthopedic correction of the distal femur to deepen the trochlear groove.
In pets that have greater limb deformity may need transposition of the tibial tubercle. Pets with the greatest deformities may need corrective osteotomy to correct for severe deformities. Surgery may be performed on one or both legs but that is determined based on individual needs.
Most patients that have had surgery are kept overnight to recover but are released the next day. We use updated pain management protocols to help patients be as comfortable as possible before, during and after surgery and when at home.
Post surgical patients tend to carry the leg when moving fast, but at a walk may be toe touching or starting to bear weight within a few days. Pets must be kept quiet and kept from being active for 2-4 weeks depending upon the surgery required, their size, age and other factors. They should be afforded to walk on surfaces with good traction such as carpeting or grass.
Physical therapy will generally include walking the pet slowly. Once started, short distances are allowed. Gradually the distance is increased. If only one leg was corrected, when the patient is using the corrected leg and is favoring the non-corrected leg, the second leg should be completed.