The CCL is one of the most important stabilizers of the knee. It prevents hyperextension, limits internal rotation, and prevents the tibia (shin bone) from sliding forward each time the leg bears weight. When the CCL is damaged, the result is an unstable knee. This instability results in pain and inflammation. Over time, debilitating arthritis develops.
Rupture of the cranial cruciate ligament (CCL, which is known as anterior cruciate ligament, ACL, in people) of the stifle joint (=knee) is one of the most common orthopedic injury in dogs. It may happen acutely as the result of a true traumatic injury (as in humans when we go skiing for example); however, this is not the norm. Most commonly it happens as a result of slow deterioration of the ligament as a dog ages. Minor trauma (that would not damage a normal ligament) finally causes it to tear completely.
The TPLO-procedure is based on investigation of the biomechanics of the dog’s knee: In contrast to the human knee, the dog’s knee has a downward slope of the tibia that exacerbates the instability in a knee with a torn CCL. In contrast the human knee does not have this slope.
You can compare this to your car standing on a hill or on a flat parking lot. On the parking lot, you won’t need to use the hand-brake, however, on a hill the car would roll without it. The hand-brake is resembled by the cruciate ligament in the dog. The TPLO procedure flattens the shin bone by rotating it – putting your car from the hill on to the flat parking lot. This makes the hand-brake (i.e. the cruciate ligament) obsolete. Hence, the TPLO provides stability to the knee during weight-bearing by altering the slope of the tibia without actually replacing the ligament.
For more information on the TPLO procedure, please click on the PDF logo, or contact us at 303-678-8844 for a free phone consultation with a surgeon.