Trauma to the equivalent ligament in humans is common, and damage most frequently occurs during some form of sporting activity (including football, rugby and golf). The nature of the injury is very different in dogs. Rather than the ligament suddenly breaking due to excessive trauma, it usually degenerates slowly over time, rather like a fraying rope.
This important difference is the primary reason why the treatment options recommended for cruciate ligament injury in dogs are so different from the treatment options recommended for humans.
In the vast majority of dogs, the cranial cruciate ligament (CrCL) ruptures as a result of long-term degeneration, whereby the fibres within the ligament weaken over time.
We do not know the precise cause of this, but genetic factors are probably most important, with certain breeds being predisposed (including Labradors, Rottweilers, Boxers, West Highland White Terriers and Newfoundlands). Supporting evidence for a genetic cause was primarily obtained by assessment of family lines, coupled with the knowledge that many animals will rupture the CrCL in both knees, often relatively early in life. Other factors such as obesity, individual conformation, hormonal imbalance and certain inflammatory conditions of the joint may also play a role. Uncorrected CrCL deficiencies have been associated with meniscal damage and degenerative joint diseases such as osteoarthritis.
TTA is a surgical procedure designed to correct CrCL deficient stifles. The objective of the TTA is to advance the tibial tuberosity, which changes the angle of the patellar ligament to neutralize the tibiofemoral shear force during weight bearing. A microsaggital saw is used to cut the Tibial Tuberosity off then a special titanium cage is used to advance the tibial tuberosity. A titanium plate is used to hold the tibial tuberosity in position. By neutralizing the shear forces in the stifle caused by a ruptured or weakened CrCL, the joint becomes more stable without compromising joint congruency.