Heather K. Streppa, DVM, MS
Diplomate American College of Veterinary Surgeons
The cranial cruciate ligament is the primary restraint against cranial drawer and hyperextension. Rupture is typically a manifestation of a degenerative condition in the dog (very rarely traumatic). Almost 100% of partial tears progress to a complete tear within 1 year and up to 60% will occur bilaterally.
Non-surgical management generally does not result in good long-term function. Many procedures have been developed to address cruciate instability. A lateral fabello-tibial suture can provide extra-capsular support, but in larger, more active dogs, failure is common. The tibial plateau leveling osteotomy (TPLO) results in neutralization of the cranial shear force that develops and has been shown to have good long-term outcomes in these patients.
The Tibial Tuberosity Advancement (TTA), developed in 2004, advances the tuberosity so that the patellar tendon is perpendicular to the tibial plateau, neutralizing tibiofemoral shear force during weight-bearing. The advanced tuberosity is held in place with a cage, fork and tension band plate (titanium or stainless steel).
The recovery period is similar to that for the TPLO procedure and reported complication rates are comparable. As with the TPLO, the TTA results in good, long-term function in any active dog and availability of implants allows the procedure to be performed in small breeds as well. When deciding between a TTA and TPLO, there are very few patient factors (excessive tibial torsion or tibial slope) that make the TPLO a more appropriate option. The TTA procedure itself is less invasive, takes less anesthesia time and the titanium implants are typically less reactive. NVS will soon be offering both procedures. Please feel free to contact me, or one of the other surgeons, for more information.