# Assessment of Femoral Trochlear Groove Depth in Canine Cadavers with Normal Stifle Joints Using Ultrasonography with the Joint Positioned at 45°, 90°, and Hyperextension, and Radiography in the Skyline Projection

## TL;DR

This study compares ultrasonography and radiography for measuring trochlear groove depth in dog cadavers, finding that ultrasonography aligns better with physical measurements.

## Contribution

The study identifies optimal ultrasonography techniques for accurate trochlear groove depth assessment in dogs.

## Key findings

- Ultrasonography showed greater agreement with caliper measurements than radiography.
- Optimal ultrasonography positions were maximal extension and 90° flexion of the stifle joint.
- Skyline radiographic projection had higher measurement variability.

## Abstract

Trochleoplasty is indicated in dogs with patellar luxation and aims to deepen the trochlear groove depth. Radiography and ultrasonography may assist in the preoperative assessment of trochlear groove depth; however, both techniques have limitations related to standardization. This cadaveric study aimed to compare trochlear groove depth measured using the skyline radiographic projection and ultrasonography at different stifle joint angles and anatomical regions, as well as to compare these findings with ex vivo measurements obtained using a caliper. Ultrasonography demonstrated greater agreement with ex vivo measurements than radiography. In addition, the skyline projection showed greater variability among measurements.

This prospective, analytical study aimed to measure and compare trochlear groove depth using skyline radiographic projection and ultrasonography at three stifle joint angles and four distinct anatomical regions, as well as to compare these findings with ex vivo measurements obtained using a caliper under the same conditions in canine cadavers without patellar luxation. A total of 67 limbs were evaluated. Ultrasonography demonstrated greater agreement with ex vivo measurements than radiography. Ultrasonographic assessment was considered appropriate for measuring trochlear groove depth with the stifle joint in maximal extension, with the transducer positioned distal to the patella, and at 90° of flexion, with the transducer positioned proximal to the patella.