Computed tomographic evaluation of canine radioulnar incongruence in vivo.

OBJECTIVE: To compare radioulnar incongruence (RUI) of normal canine elbows and elbows with arthroscopically confirmed medial compartment disease in vivo using systematic computed tomography (CT) measurements.

STUDY DESIGN: Prospective comparison of RUI measurements in normal and dysplastic canine elbows.

SAMPLE POPULATION: Right elbows of 25 medium-large breed, adult dogs with medial compartment disease and 9 medium-large breed, adult dogs with no elbow disease.

METHODS: Transverse CT images of proximal radioulnar articulation were reformatted to dorsal and sagittal planes. RUI in 3 locations of the forelimb's medial coronoid was measured. Arthroscopy confirmed diagnosis of medial compartment disease in the diseased group. RUI measurements of the diseased and normal elbows were compared.

RESULTS: Cumulative statistical analysis of RUI in all planes revealed no significant difference between the normal and abnormal elbows (P = .61). The abnormal elbows had negative mean RUI at the mid (P = .56) and cranial (P = .24) coronoid regions that were not significantly different from normal elbows and mean positive RUI at the base coronoid that was significantly greater than in normal elbows (P = .00082).

CONCLUSION: Canine elbows with established medial compartment disease do not have significant RUI at the medial coronoid region at the time of diagnosis when compared with normal elbows.

CLINICAL RELEVANCE: If RUI is a significant factor in the pathophysiology of medial compartment elbow disease in the dog, it does not appear to be present at the time of diagnosis of disease. Ulnar or radial osteotomies do not appear to be indicated for restoration of normal radioulnar articular surface alignment.