Evaluation of elbow incongruency using reconstructed CT in dogs suffering fragmented coronoid process

OBJECTIVES: A retrospective study was undertaken to evaluate elbow joint congruency in dogs suffering fragmented coronoid process (FCP). METHODS: Based on clinical, radiographic and computed tomographic (CT) examinations, elbows were divided into control and FCP groups. Standardised CT reconstructions were formatted in the frontal and sagittal planes. Humeroradial and humeroulnar joint space measurements were obtained from the Images and incongruencies were calculated by comparing the two measurements. RESULTS: Forty-two FCP and 29 control elbows were identified. No incongruencies were noted at the coronoid base. At the level of the coronoid apex, FCP elbows exhibited a significant radioulnar incongruency compared with controls (P < 0.0001), though incongruency was not identified in all cases. Comparing FCP and control elbows at the level of the apex, the humeroradial joint space was increased in FCP elbows (P = 0.0006) whereas no difference was noted in the humeroulnar space. CLINICAL SIGNIFICANCE: This study supports the hypothesis that joint incongruency is associated with FCP in dogs, though is not present in every case at the time of diagnosis. The precise mechanism of development of this incongruency cannot be determined from these data.