There are many different types of surgeries to stabilize knees with torn ACLin dogs and cats. The surgical procedures available can be categorized based on different principles such as ligament replacement versus angle correction (osteotomy) technique.
The angle correction surgeries include TPLO (tibial plateau leveling osteotomy), and TTA (tibial tuberosity advancement). These techniques are performed in large breed dogs over 40 to 50 lbs, and most athletic patients.
The ligament replacement technique also called lateral suture stabilization, mimics the function of the torn ACL and it is placed in the same orientation of the normal ACL. This surgery is indicated for patients that are small (less 40 lbs), old and less active.
HOW DOES THE TPLO (TIBIAL PLATEU LEVELING OSTEOTOMY) PROCEDURE WORK?
Tibial Plateau Leveling Osteotomy (TPLO) involves making a cut into the tibial bone (shin) and rotate the top of the bone until stability is achieved. Once the desired rotation is obtained, a bone plate with screws is placed. With this technique, the ligament is not necessary, therefore it does not need to be replaced. The plate and screws could be removed once the bone has healed if there is any rejection or infection.
TPLO technique is a superior procedure over the ligament replacement because it does not rely on scar tissue like the ligament surgery, however biomechanical changes. The perceived advantage of the TPLO is the superior long term outcome with minimal progression of arthritis.
Regarding potential complications of TPLO, which are rare, include implant rejection, failure of bone union and infections. To prevent complications the procedure should be performed by a boarded surgeon.
HOW DOES THE TTA (TIBIAL TUBEROSITY ADVANCEMENT) WORK?
Tibial Tuberosity Advancement (TTA) as the TPLO surgery requires a cut along the shin bone.
The TTA achieves the same mechanical stability of the TPLO and the bone cut is stabilized with bone plate and screws. The advantages and disadvantages of the TTA are similar to the TPLO.
IS THE TPLO SUPERIOR TO THE TTA?
The decision to perform TPLO versus TTA is based on the surgeon’s experience and opinion, and no publications can support one surgery versus the other. TTA and TPLO achieve the same outcome in stabilizing the knee with a deficient ligament by making a cut in the bone and using bone plates.
HOW DOES THE PROSTHETIC LIGAMENT WORK?
The ligament replacement procedure is performed by placing a fake ligament (monofilament nylon), from the upper bone (femur) to the lower bone (tibia) in similar orientation to the natural ACL. The stability of the knee is obtained by the organized scar tissue that develops around the joint. The main disadvantage of the surgery includes failure of prosthetic ligament, infection and need for additional surgeries. For this procedure, the bone is not cut and no specialized equipment is needed.