Role of Elbow Incongruity in Canine Elbow Dysplasia: Advances in Diagnostics and Biomechanics

Elbow incongruity plays an important role in the development of elbow dysplasia and its diagnosis can be challenging. The objectives of this systematic review were to discuss elbow biomechanics and recent advances in the assessment of incongruity, to revise the diagnostic protocols suggested, debate advantages and disadvantages of measurements proposed to characterize the joint and improve screening. In spite of advances in the understanding of elbow incongruity, the exact mechanisms involved are not fully elucidated. The elbow is a complex joint and structures in contact differ in different phases of the gait cycle. Advances in the biomechanical field allowed new discoveries and a physiological type of incongruity was described. The next challenge is to unravel the dynamic incongruity. Radiology and computed tomography (CT) are nowadays the imaging tools more applied in clinical practice to quantify incongruity. But a CT standardized screening protocol is required. Most reported findings of incongruity were increased articular joint spaces. The proximity of joint structures and standardization of elbow positioning are identified as the main obstacles to a good interpretation. This review serves to highlight controversy between physiological types of cartilage covering described and pathological changes reported in arthroscopic studies. Radioulnar incongruity was reported more often than humer-oulnar incongruity, yet prevalence studies are lacking. Sensitive and reproducible methodologies are in development, which seem primordial to assess the phenotypic heterogeneity.