What Is The Patella
The patella or knee cap is a small piece of bone, covered in cartilage, that lies within the patellar ligament. This ligament runs from the quadriceps muscles to the tibia and allows the knee to flex and extend with muscle movement. The patella sits in a groove in the top of the femur which helps hold it in place.
What Is A Patella Luxation
Patella luxation is when the knee cap pops out of the normal groove it typically sits in. More commonly the knee cap moves to the inside of the knee; this is called a medial patella luxation.
What Causes A Patella Luxation
Most small breed dogs are born with conformational abnormalities that result in a patella luxation. These include a shallow groove in the femur and a slight bow to the leg which encourages the luxation to happen. In congenital cases, the luxation is often bilateral although one leg may be worse than the other. Common breeds include the Maltese, Yorkshire Terrier, Pomeranian, and any other small/toy breed. Less commonly, patella luxations can be seen in large breed dogs.
Symptoms Of A Patella Luxation
Most dogs have an intermittent skip or limp seen in the affected leg. When the patella luxates, the dog will usually hold the leg up and then can be seen kicking or extending the leg in an attempt to put the patella back in place.
Patella laxations can be associated with other knee injuries including cranial cruciate ligament tears, meniscal injuries, and arthritis. Dogs with these other diseases or large breed dogs usually have a more consistent or severe limp.
Grades Of Patella Luxation
Luxations are graded on a scale of 1 to 4, based on their severity. The higher the grade of luxation, the more time the patella is out of place/luxated and the harder it is to reduce/correct the luxation.
How Are Patella Luxations Treated
Unfortunately, there is no medical treatment to correct a luxation. Anti-inflammatories and pain medications are used to control the discomfort from the patella being out of place. Dogs that limp from a patella luxation usually require surgical correction. Surgery involves two primary procedures performed simultaneously. These include deepening the groove the patella sits in (trochleoplasty) and re-aligning the quadriceps mechanism. The later is accomplished by moving the bone of the tibial crest, where the patellar ligament inserts, laterally and securing it in place with metal pins.
Recovery From Surgery
Dogs spend one night in the hospital following the procedure. Patients are discharged with anti-inflammatories, pain medications, and directions for at-home rest and rehabilitation. Total recovery time is approximately 8 weeks.
Outcome After Surgery
Most dogs with grade 1 to 3 luxations have successful surgeries that return the patella to a normal position. This allows the pets to return to an active lifestyle. Grade 4 luxations are much more challenging to correct and may require additional procedures (femoral osteotomies) and/or multiple surgeries. The higher the grade of luxation, the greater the risk of surgical complications (ie, recurrent luxation).
At Elite Veterinary Surgery, this surgery is completed by a board certified surgeon who has undergone extensive training in the procedure. Patients receive multi-modal pain control including injectable medications, oral medications, a local nerve block, and topical therapies. Patients recover in our 24-hour care facility and are monitored by a full team of doctors and technicians. During all times of the recovery process, you and your dog have immediate access to the surgeon who performed the surgery.