Strain Elastography and B-Mode Ultrasound of the Quadriceps Femoral Muscle and the Femoro–Tibio–Patellar Joint of Healthy Dogs and Dogs with Cranial Cruciate Ligament Rupture

This study analysed alterations in the stifle and quadriceps femoris muscle of healthy dogs and dogs with cranial cruciate ligament rupture using ultrasound and strain elastography.B-mode ultrasound was performed bilaterally in the stifle and quadriceps femoris muscle of the animals from both groups, healthy animals (HA, <i>n</i> = 16) and diseased animals (DA, <i>n</i> = 10), using strain elastography with strain ratio measurement.The strain ratio means between infrapatellar fat pad/patellar ligament were 0.92 ± 0.29 in the right pelvic limbs and 1.1 ± 0.51 in the left pelvic limbs for group HA and 1.7 ± 0.9 in the right pelvic limbs and 1.8 ± 1.0 in the left pelvic limbs for group DA. As for the strain ratio between infrapatellar fat pad/cranial cruciate ligament, the means were 1.1 ± 0.36 in the right pelvic limbs and 1.1 ± 0.52 in the left pelvic limbs for group HA and 2.7 ± 1.2 in the right pelvic limbs and 2.6 ± 0.96 in the left pelvic limbs for group DA. The ratio in group DA increased, showing statistical significance in the mean comparison, thus indicating higher stiffness in the patellar ligament and CCL of diseased animals. The main B-mode ultrasound findings in the DA group include suprapatellar recess effusion, osteophyte proliferation, and meniscal alterations. Seven dogs had increased echogenicity in the vastus medialis muscle, which was associated with higher elasticity but potentially related to alterations, such as necrosis and inflammation.The increased cruciate ligament stiffness suggests its application as an early indicator of degenerative alterations.