The TTA or Tibial Tuberosity Advancement Procedure is based on the research that the patellar ligament can stabilise the joint if it is at a 90-degree angle to the tibial plateau. During weight bearing, the femur slides down the tibial plateau caudally. The anterior cruciate ligament (ACL) acts against this downward force. The surgery changes the biomechanics of the stifle joint (redirecting the strong muscular forces of the muscles on the front of the thigh) so that stability is created without applying an artificial physical restraint across the joint. This technique offers more advantages than other surgical techniques by being less invasive and faster to perform. The patients undergoing this procedure do not need to wear any form of bandage when going home. By advancing the tibial tuberosity in an ACL deficient knee, the patellar ligament is adjusted perpendicular to the tibial plateau. This eliminates the tendency of the femur to move downward over the sloped plateau. The patellar ligament is one of the toughest ligaments in the body, and it is completely controlled by one of the biggest muscles in the body, the quadriceps muscle on the front of the leg. Dogs having a steeper slope are more predisposed to rupturing the ACL. The TTA aims to correct for this slope by adjusting the angle between the tibial plateau and the patellar ligament. By advancing the tibial tuberosity, we can overcome the abnormal front to back motion called tibial thrust, and also tend to overcome the tendency for pivot shift or rotation of the tibia relative to the femur.  Current thought is that this procedure leads to less arthritic change in the joint.  This procedure can be successfully done on any size dog, and is currently the treatment of choice by many surgeons.