Animal Medicine, Production and Health, Università degli Studi di Padova Scuola di Agraria e Medicina Veterinaria, Legnaro, Italy.
Clinic for Small Animal Surgery, University of Zurich, Zurich, Switzerland.
Vet Rec. 2019 Oct 12;185(14):443. doi: 10.1136/vr.105326. Epub 2019 Jul 10.
The purpose of the study was to evaluate the accuracy of a three-dimensional (3D) automated technique (computer-aided design (aCAD)) for the measurement of three canine femoral angles: anatomical lateral distal femoral angle (aLDFA), femoral neck angle (FNA) and femoral torsion angle.
Twenty-eight femurs equally divided intotwo groups (normal and abnormal) were obtained from 14 dogs of different conformations (dolicomorphic and chondrodystrophicCT scans and 3D scanner acquisitions were used to create stereolithographic (STL) files , which were run in a CAD platform. Two blinded observers separately performed the measurements using the STL obtained from CT scans (CT aCAD) and 3D scanner (3D aCAD), which was considered the gold standard method. C orrelation coefficients were used to investigate the strength of the relationship between the two measurements.
A ccuracy of the aCAD computation was good, being always above the threshold of R of greater than 80 per cent for all three angles assessed in both groups. a LDFA and FNA were the most accurate angles (accuracy >90 per cent).
The proposed 3D aCAD protocol can be considered a reliable technique to assess femoral angle measurements in canine femur. The developed algorithm automatically calculates the femoral angles in 3D, thus considering the subjective intrinsic femur morphology. The main benefit relies on a fast user-independent computation, which avoids user-related measurement variability. The accuracy of 3D details may be helpful for patellar luxation and femoral bone deformity correction, as well as for the design of patient- specific, custom-made hip prosthesis implants.
本研究旨在评估一种三维（3D）自动化技术（计算机辅助设计（aCAD））测量三个犬股骨角度的准确性：解剖外侧远端股骨角（aLDFA）、股骨颈角（FNA）和股骨扭转角。
从 14 只不同形态（长骨型和软骨发育不良型）的犬中获得 28 根股骨，将其平均分为两组（正常组和异常组）。对所有股骨进行 CT 扫描和 3D 扫描仪采集，以创建立体光刻（STL）文件，这些文件在 CAD 平台上运行。两名盲法观察者分别使用 CT 扫描获得的 STL（CT aCAD）和 3D 扫描仪（3D aCAD）进行测量，后者被认为是金标准方法。使用相关系数来研究两种测量方法之间的关系强度。
aCAD 计算的准确性良好，在两组中，所有三个角度的 R 值均大于 80%，均高于阈值。aLDFA 和 FNA 是最准确的角度（准确性>90%）。
所提出的 3D aCAD 方案可被视为一种可靠的技术，可用于评估犬股骨的股骨角度测量。所开发的算法可自动在 3D 中计算股骨角度，从而考虑到股骨的内在形态。主要优势在于快速、用户独立的计算，避免了用户相关的测量变异性。3D 细节的准确性可能有助于治疗髌骨脱位和股骨畸形矫正，以及设计特定于患者的定制髋部假体植入物。
