CTassessment of the influence of dynamic loading on physiological incongruency of the canine elbow

Abstract

To present a novel technique for loading of the canine elbow joint and to quantify changes in congruency with increasing load using computed tomography. Five pairs of thoracic limbs were mounted at a mid stance angle in a custom made jig. Elbow joints were loaded to 0, 33, 66 and 100% of total individual cadaver bodyweight. At each load computed tomography of the elbow was performed. Joint space measurement was performed on sagittal plane central, lateral and medial compartment images at humero-radial (R1 , R2 , R3 ), humero-ulnar (U1 , U2 ) and radio-ulnar loci. The effect of loading on joint spaces was assessed (P<0.05). With increasing load; for central an increase in R1 and radio-ulnar distance and decreased R3 occurred; for medial R1 increased; and for lateral R1 and radio-ulnar distance increased. The largest increases were seen in the lateral compartment. Significant changes in humero-radio-ulnar congruency occurred suggesting pronation of the radius with respect to the ulna was induced during loading. This movement may influence the load experienced by the medial coronoid process and could play a role in the aetiopathogenesis of medial coronoid process disease.