Bone density of elbow joints in Labrador retrievers and Golden retrievers: Comparison of healthy joints and joints with medial coronoid disease

• Hounsfield units (HU) and bone density (BD) measurements were determined in normal and diseased canine elbow joints.
• HU and BD values in regions of the medial coronoid process (MCP) base and apex were related to medial coronoid disease.
• Labrador retrievers had higher HU and BD values than Golden retrievers.
• An increase in bone density in the MCP was found in older animals.
• Fairly good sensitivity and specificity values were determined for the MCP base and apex.

The aims of this study were: (1) to determine the inter-observer repeatability of particular regions of the canine elbow joints; (2) to assess the effect of age, bodyweight and breed on bone density in healthy young dogs; (3) to compare Hounsfield units (HU) and bone density (BD) measurements between normal elbow joints and diseased elbow joints; and (4) to determine the sensitivity and specificity for HU and BD measurements in specific regions in the canine elbow joint. Regions with the highest repeatability were located at the medial coronoid process (MCP) base and apex, and at the level of the humerus, on the sagittal and sagittal oblique planes of the elbow joint. Age and breed were significantly associated with several regions of interest; conversely, none of the measurements were associated with bodyweight. Increased HU and BD values in the MCP base and apex regions are likely to be related to medial coronoid disease. Labrador retrievers had higher HU and BD values than Golden retrievers and an increase in BD was found in older animals. Cut-offs determined with receiver operating characteristic plots of the MCP base and apex suggested fairly good sensitivity and specificity (base: area under the curve 0.85, sensitivity 75.0%, specificity 88.8%; apex: area under the curve 0.89, sensitivity 80.0%, specificity 92.5%).