Radiographic, Ultrasonographic and Shear Elastosonographic Changes in Patellar Ligament in Dogs Undergoing Tibial Plateau Leveling Osteotomy

This study aims to evaluate the morpho-functional changes in the patellar ligament in dogs undergoing tibial plateau leveling osteotomy (TPLO) during the first six months of the postoperative follow-up and correlate the radiographic and conventional ultrasonography changes in the patellar ligament with its elastic properties. Dogs with a unilateral cranial cruciate ligament (CCL) rupture who underwent TPLO were enrolled. The patients were subjected to radiographic, ultrasonographic and elastosonographic evaluations of the patellar ligament before surgery (T0) and 1 month (T1), 2 months (T2) and 6 months (T3) after surgery. The radiographic and ultrasound thicknesses of the patellar ligament were recorded at three points: proximal, central and distal. A color map of strain elastosonography with superimposed B-mode images was used to evaluate the elasticity (hardness and softness) of the ligament. Twenty-two dogs completed the trial. At T0, the patellar ligament showed statistically reduced radiographic and ultrasonographic thicknesses compared to those at T1, T2 and T3. Additionally, the patellar ligament in the distal portion was statistically thicker in comparison to the proximal and central points at T2 and T3. At T1, T2 and T3, there was an increase in hardness and a reduction in softness of the patellar ligament compared to that at T0. The elastosonographic analysis and the radiographic and ultrasonographic thicknesses of the patellar ligament showed no correlation. The patellar ligament showed structural and mechanical alterations in the dogs undergoing TPLO, even six months after surgery.