Tibial Plateau Leveling Osteotomy or TPLO, is a well established procedure performed on dogs to stabilize the stifle (knee) after a rupture of the Cranial Cruciate Ligament (CrCL). This surgery is typically performed in larger, active dogs. Approximately ninety percent of dogs undergoing the TPLO procedure will experience a faster recovery time than traditional knee stabilizing surgeries, will regain pre-injury activeness and range-of-motion, and will have minimal post-operative side effects. Tibial plateau leveling osteotomy, TPLO, is a specialized surgery and should be performed by a board certified veterinary surgeon.
Dogs that suffer an injury to the cranial cruciate ligament will lose stability of the knee joint. The result is a reduction in mobility and range of motion, and the progression of chronic arthritis begins. The TPLO, tibial plateau leveling osteotomy, is used to resolve cranial tibial thrust, resulting in a stable stifle joint during weight bearing. In essence this means that the cranial cruciate ligament normally prevents the tibia from sliding forward. When the cranial cruciate ligament is torn this movement needs to be prevented. A TPLO procedure effectively “levels” the top surface on the tibia (shin bone) so forces are shifted forward and the tibia no longer slides forward with respect to the femur (thigh bone).
The TPLO surgery begins by cutting out the ruptured ends of the cruciate ligament. An examination of both the medial and lateral menisci is then performed through an open arthrotomy or via arthroscopy. Up to fifty percent of the dogs that tear the cruciate ligament will also suffer from a torn medial meniscus. This occurs because the shift of the tibia forwards pinches and damages the medical meniscus. This action will tear the caudal or back part of the meniscus and flip it forward. During the TPLO procedure, every effort is made to save the majority of the uninjured meniscus, only removing the damaged portions. Either an arthroscopy (examination and cleaning of the joint by a camera), or arthrotomy (cleaning of the open joint) is performed. Arthroscopy or an open arthrotomy performed before the tibial plateau leveling osteotomy will allow for a clear view of the injury and the ability to clean the joint of debris. The surgeon performing the TPLO, will make a curved incision at the top of the tibia bone, including the tibial plateau. The tibial plateau is turned along the curved cut made at the top the tibia in order to align the slope. A surgical plate and screws are placed to keep the tibial plateau in the correct position for healing. For optimal healing, the degree for the tibial plateau following TPLO should be set between two and fourteen degrees. A five degree slope is the most recommended setting for veterinarians performing successful tibial plateau leveling osteotomy procedures. Post-operative radiographs (x-rays) of the affected knee will allow evaluation the success of the TPLO procedure, and will ensure the degree of slope to the tibial plateau is optimal for healing. Because the TPLO is an osteotomy (bone cutting and moving procedure), a qualified orthopedic surgeon also has the ability to make some additional corrections to a malformed knee during the procedure that may prevent future problems for the patient as well.