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For video animation of TTA procedure start video at 6:06 |
Purpose |
The Tibial Tuberosity Advancement procedure seeks to eliminate tibial translation and tibiofemoroal shear force by positioning the patellar tendon perpendicular to the shear forces in the stiffle
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Understanding the problem |
This concept if strictly based on the laws of motion and forces found in physics. When a dogs paw is loaded with weight and force from the patellar tendon, the dog is doing work on the ground. Newtons 3rd law of motion states that with every action there is an equal and opposite reaction. Therefore the normal force coming from the ground dose work on the dog, and theoretically should balance out the forces. Although, since a dogs stifle is orientated at 135 degrees, the normal force opposes the initial patellar tendon force on an angle, resulting in a tibiofemoral shear force ( in the direction of tibial translation), which is accommodated for in a normal pet stifle by the CCL. In the typical joint, the angle formed between the Tibial Plateau and the patellar tendon is about 115 degrees when the leg is in a normal standing position. By performing the TTA procedure and advancing the Tibal Tuberosity, the slope of the tibial plateau is anatomically orientated at 90 degrees to the patellar tendon on weight bearing, thus leaving he sum of the vector forces 0 and there is no longer tibial translation.
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How to fix ithttp://scah.us/the-surgery.pml
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1. The ruptured cruciate ligament is removed and medial meniscus damaged is assessed.
2. A drill guide is placed on the tibial tuberosity, the holes are the attachment site for the plate 3. The tibia tuberosity is cut and advanced forwards. 4. A plate is screwed in place. The lower end attaching to the tibia and the upper end attaching to the advanced tibial tuberosity. 5. An advancement cage is placed in the osteotomy site and screwed in place 6. The procedure is complete and the surgical site is sutured up *** Refer to video below found under the visual header of this page for TTA animation*** |