Objective: To evaluate the accuracy of 3 femoral craniocaudal radiographic techniques in assessment of femoral morphology using CT scans as the imaging modality of choice.
Methods: Candidates were assessed from September 2024 through October 2025, and those with a normal orthopedic examination were enrolled. Extended limb, sitting position, and horizontal beam radiographs and CT scans were evaluated for frontal plane alignment, with the following measurements completed by 2 investigators independently: anatomic lateral distal femoral angle (aLDFA), mechanical lateral distal femoral angle, anatomic lateral proximal femoral angle, and mechanical lateral proximal femoral angle. Angles were statistically compared (P < .05) between groups, and interobserver variability was evaluated.
Results: Femoral morphology of 25 dogs (50 femora) with body weights ranging from 14 to 45 kg was assessed. Horizontal beam was most accurate for anatomic lateral proximal femoral angle, mechanical lateral proximal femoral angle, and aLDFA, whereas extended limb was most accurate for mechanical lateral distal femoral angle, with each showing no significant difference from CT. Sitting position was not the most accurate for any measurement. All measurements demonstrated high interobserver agreement (intraclass correlation coefficient > 0.8 for all parameters).
Conclusions: Proximal and distal canine femoral morphology can be reliably measured by specific radiographic views in the absence of CT.
Clinical relevance: In the absence of a CT scan, horizontal beam is recommended for accurate assessment of proximal femoral morphology in planning of total hip replacement and also demonstrated superiority when considering aLDFA measurements used for patellar luxation surgery planning.
