What Is TPLO Surgery?
 TPLO Surgery, or Tibial Plateau Leveling Osteotomy is a procedure typically done to repair a rupture of the cranial cruciate ligament in a dogs knee.

Unforunately for dogs, their knees are designed in such a way that there is constant stress on the cruciate ligament, which is the ligament which holds the joint between the femur (the upper leg), and the tibia (the lower leg) together.

As you can see in the image below, the angle between the femur (the bone on top), and the tibial slope (the slighty curved top portion of the bottom bone) is not perpendicular to the tibia. During activity the femur actually slides backwards down the tibial slope, forcing the tibia forward, placing contact stress on the cruciate ligament. The risk of cruciate ligament tear increases if your dog is overweight, has an excessively steep tibial slope, or during intense exercise such as jumping. TPLO surgery relieves the tension on the cruciate ligament by chaning the angle between the femure and the tibial slope to an angle of approximately 2 to 14 degrees. This slight angle prevents the femur from sliding back on the tibial slope, reducing stress on the cruciate ligament.

When is TPLO Surgery Necessary?
Cruciate ligament ruptures typically in older, large breed, and overweight dogs, and any damage to the ligament or meniscus requires surgery. The severity of symptoms depends on several factors:
*  If the meniscus is torn. Meniscal tears are very painful; if your dog tears his / her meniscus, it is likely the leg will be completely lame. In other words, your dog will hold the leg up and will not place any weight on the leg. If your dog has a high pain threshold (such as bulldogs), it is possible they will still be weight bearing. If you hear a persistent audible clicking noise coming from the knee, it is very likely your dog has torn their meniscus.

•   The severity of the cruciate ligament damage
•    Your dogs overall weight and health

Signs of lameness can very from acute discomfort and disuse of the leg to intermittent signs of discomfort. If your dog occasionally holds their leg off of the ground and appears to be "searching" for the floor with his foot, this is a sign of ligament damage.

Definitive diagnosis of ligament and meniscus damage can only be done by physical evaluation by a qualified TPLO surgeon. The knee joint will be manipulated and tested for stability.

Upon diagnosis, your surgeon will schedule an appointment to take X-rays while your dog is under sedation. These xrays will be used to measure your dogs tibial slope and for planing the surgical repair.

What Is Done During TPLO Surgery?
TPLO surgery is generally a very techincal yet relatively fast surgery, lasting from 45 to 90 minutes

During TPLO surgery, the surgeon will:

•  Remove and repair the torn pieces of the cruciate ligament
•  Remove any torn peices of meniscal cartilage (fix the meniscus). Every attempt to save as much of the meniscus is made.
•  Cut a curved portion in the top of the tibia, including the tibial plateau. This is the osteotomy portion of the surgey.
•  Based on measurments taken from xrays, the surgeon will rotate the tibial plateau, leveling the tibial slope.
• A stainless steel plate will be screwed into the tibial plateau and the base of the tibia to hold the osteotomy in place while the bone heals.

A tear in the cruciate ligament typically results in some degree of lameness in the leg. Early identification and application of TPLO Surgery can reduce the chance of arthritis, cartilage damage such as meniscal tears (the meniscus is the cartilage padding between the bottom end of the femur and the top end of the tibia).