Comparison of Ultrasonographic, Radiographic, Computed Tomographic, and Ex Vivo Measurements of Feline Femoral Trochlear Groove Depth

Patellar luxation is a common orthopedic condition in cats, and evaluation of trochlear groove depth is important to determine the need for trochleoplasty during surgical planning. This study compared radiography, ultrasonography, and computed tomography with ex vivo measurements, considered the reference method, for the assessment of trochlear groove depth in cats. Twenty-seven stifle joints from 15 healthy adult cats were evaluated. Trochlear groove depth was measured using skyline radiographic projections, ultrasonography with the stifle positioned at 45° and 90° of flexion, computed tomography, and ex vivo evaluation with the stifle flexed at 45° and 90°. Measurements obtained by radiography and ultrasonography with the stifle positioned at 90° did not show significant differences compared with the respective ex vivo measurements at 90°, whereas ultrasonography performed at 45° and computed tomography differed. The results obtained by radiography and ultrasonography at 90° suggest that these techniques provide reliable estimates of trochlear groove depth in healthy cats. These findings support the use of radiography and ultrasonography as reliable imaging methods for preoperative evaluation and surgical planning in cats with patellar luxation.