Patella Luxation (MPL Surgery)
Patella Luxation (Knee Cap Luxation)
The patella (knee cap) is a small bone in the knee joint like ours that can dislocate itself in dogs and cats. The kneecap glides in a groove in the femur in a normal joint. The patella is attached to the quadriceps muscle on the femur and then to the tibia via the patellar tendon. Any alignment changes where the quadriceps and patellar tendon are not in a straight line can cause it to luxate or dislocate out of the femoral groove. Due to several causes such as a shallow femoral groove, loose ligaments, and/or a femoral bone twist, the patella may be dislocated out of the groove and cause lameness, pain and arthritis. Although this is a disease typically of small breed dogs, large breed dogs can also be affected.
How is patella luxation diagnosed?
You, your family veterinarian, and Dr Jha (Board Certified Surgeon) will use several diagnostic tools to confirm a patella luxation in your pet friend. You may notice lameness mainly with a “skipping gait” in your dog and your dog lifting the affected leg intermittently. Your primary care veterinarian will detect pain and a dislocated patella on physical exam. We complete the diagnostic process by performing a thorough orthopedic and neurological examination, follow up x-rays under sedation or general anesthesia. In many dogs we recommend a CT scan to diagnose the complex causes of patella luxation and plan for surgical correction. An experienced surgeon can palpate the knee joint with patella luxation and generally be able to tell the grade of luxation and recommend the level of treatment needed. Patella luxation is divided into grades I,II, III, and IV. Grade III and IV generally need a surgical correction and in some instances a patella luxation of grade II can also benefit from surgical treatment.
How is patella luxation treated?
Medical management and rehabilitation is rarely recommended if your dog has long lasting lameness and is refractory to medical management due to patella luxation. Grade III and IV patella luxation can results in severe lameness and may cause rupture of the Cranial Cruciate Ligament.
The reshaping of the bone and aligning the quadriceps muscle to patellar tendon is the main principle we follow to bring a dislocated patella back in the femoral groove.
- Tibial tuberosity transposition
- Deepening of femoral groove
- Tightening of the soft tissue
- Corrective osteotomy of the femur