Radiographic, computed tomographic, and arthroscopic diagnosis of radioulnar incongruence in dogs with medial coronoid disease.

OBJECTIVE

To characterize radioulnar incongruence (RUI) in large dogs with medial coronoid disease (MCD) and determine the agreement between radiography, computed tomography (CT), and arthroscopy.

STUDY DESIGN

Prospective observational case series.

ANIMALS

Twenty-four large-breed dogs under 3 years of age with confirmed MCD.

METHODS

MCD and incongruence were evaluated by radiographs and CT. RUI was measured along the ulnar commissure, mid-body, and apex of the medial coronoid process (MCP) by CT and arthroscopy. Joints with RUI ≥ 2 mm were considered incongruent. Variables recorded during arthroscopic treatment included type of MCD, RUI, and modified Outerbridge score. Agreement between the 3 diagnostic imaging techniques was evaluated, and the association between RUI and cartilage damage was analyzed.

RESULTS

Single fragmentation was the most common MCD according to CT and arthroscopy. RUI was associated with degenerative joint disease according to CT and with cartilage damage according to arthroscopy. RUI was diagnosed in 26% of elbows by radiography, in 35% of elbows by CT, in 78% of elbows according to CT measurements of RUI ≥ 2 mm, and in 57% of joints by arthroscopy. RUI was most commonly detected at the ulnar commissure with CT and at the apex of the MCP with arthroscopy. Imaging modalities were in poor to fair agreement with arthroscopy when evaluating RUI.

CONCLUSION

CT and arthroscopy provided similar detection of MCD and cartilage disease but disagreed in the assessment and localization of RUI.

CLINICAL SIGNIFICANCE

CT does not reliably predict arthroscopic assessment of RUI and associated treatment decisions for MCD.