TPLO - Tibial Plateau Leveling Osteotomy

A Technique for Treating Ligament Damage in Dogs and Cats

You've just been told by your veterinarian that your dog is limping on his / her rear leg because he / she has a torn anterior cruciate ligament in the knee [stifle]. He has recommended surgery. What are your options?

Just as in human medicine, Veterinary medicine has board certified specialists, and while you trust your doctor, a second opinion is always indicated, and should never be thought of as an insult to your regular veterinarian.

As to the injury [torn ligament], it is the same injury seen in human athletes ["football knee"]. There are two ligaments inside the dog's knee which cross, thus the name "cruciate" ligaments. These ligaments provide stability for the knee when the dog walks. If the anterior cruciate tears [by far the most common knee injury], the shin bone moves forward when the dog walks. This causes pain, and can damage the cartilage [meniscus] inside the knee. Over the years many techniques have been developed and used to stabilize the stifle.

However, the majority of large dogs [over 50 pounds] whose stifles were repaired by conventional methods, while initially doing well, developed arthritic changes within six months, as though no surgery had been performed.

In 1995, a new technique was developed which would allow for large dogs to have a 90+% chance of returning to preinjury function without the development or progression of arthritic changes. This procedure, now performed by "licensed" surgeons, is called Tibial Plateau Leveling Osteotomy [ TPLO ].

To better understand this technique, we must understand that artificially created ligaments can only achieve about 30% of the strength of the original ligament. Therefore we must now consider a different way to look at the anterior cruciate deficient stifle. We no longer look at the elimination of the forward movement called the "anterior drawer sign" and address our attention at a more active model.

With the absence of a ACL, the thigh [femur] slips off the back of the shin bone [tibia] forcing it forward when the dog walks [cranial tibial thrust]. The purpose of TPLO surgery is to eliminate the cranial tibial thrust by changing the angle of the top [plateau] of the tibia. thus preventing the femur from riding off the back of the tibia and forcing it forward. To accomplish this, the tibial plateau must be cut, rotated, and held in place with stainless steel plate and screws. This now creates a level surface, and the femur no longer falls off the back of the tibia.

While this procedure was first developed for use in large dogs [over 50 pounds], new equipment is now available for small dogs and cats [even as small as 5 pounds].

In summary, the advantages of this procedure over previous conventional methods is:
• Quicker recovery, full weight bearing usually within 2 weeks
• No need for a postoperative dressings.
• Greater than a 90% chance of return to preinjury function [household pet, working and show].

It is therefore, at this time considered by the majority of surgeons to be the ideal procedure for cruciate deficient stifles on dogs and cats.