Effects of Femur Position on Radiographic Assessment of Femoral Head and Neck Excision Completeness in Cats

Abstract

Objective The aim of this study was to determine the effect of femoral position on radiographic assessment of completeness of femoral head and neck excision (FHNE) in cats. Study Design The study included 20 femurs from adult cats. Complete FHNE was performed on 10 femurs and incomplete excision consisting of inadequate excision of the distal medial femoral neck was performed on 10 femurs. The lesser trochanter was maintained in all femurs. Each femur was positioned through a predetermined set of eight radiographic views about the long axis. Sensitivity (SE), specificity (SP) and accuracy were calculated for each femoral position. Results Craniocaudal views of the femur in external rotation (30° and 45°) had the highest SE, SP and accuracy (SE: 97.5% and 97.5%; SP: 92.5% and 95%; and accuracy: 95% and 96%, respectively) followed by external rotation of 15 (SE: 92.5%, SP: 87.5% and accuracy: 90%) relative to standard craniocaudal (SE: 57.5%, SP: 72.5%, accuracy: 65%) and lateromedial (SE: 2.5%, SP: 0%, accuracy: 1%) radiographic views. Conclusions Evaluation of craniocaudal radiographic views with the femurs in external rotation can increase the ability to assess the adequacy of the FHNE in cats.