Abstract
OBJECTIVE: To quantify the morphology of the humeral condyle in dogs with and without humeral intracondylar fissure (HIF). STUDY DESIGN: Retrospective case control. SAMPLE POPULATION: A total of 171 elbows. METHODS: Computed tomography (CT) scans of elbows were retrospectively analyzed. The population comprised three groups; non-chondrodystrophic control dogs (n = 44), Springer Spaniel control dogs (n = 27), and humeral intracondylar fissure (HIF)-affected dogs (n = 100). A condylar template was constructed on three-dimensional (3D) surface-rendered images with measurement of 10 parameters by three observers. RESULTS: A total of 171 elbows were analyzed. Angle A, representing the axial surface of the medial humeral condyle and angle B, representing the axial surface of the lateral humeral condyle were both significantly greater in HIF-affected dogs (p < .001). Length a (p = .007) and b (p < .001), representing the vertical distance between the most proximal and most distal points of the medial and lateral humeral condyles respectively, were also significantly greater in HIF-affected dogs. CONCLUSION: From the population sampled, HIF-affected dogs had both significantly greater vertical height as well as angulation of the axial surface of both the medial and lateral humeral condyle. CLINICAL SIGNIFICANCE: Greater angulation of the axial surfaces of the humeral condylar articular surface could create an intracondylar shear force orthogonal to the orientation of the fissure, predisposing to HIF formation.