Comparison of the radius of curvature of the ulnar trochlear notch of Rottweilers and Greyhounds

Objective-To compare radius of curvature along the ulnar trochlear notch of Rottweilers and Greyhounds to determine whether morphologic differences ex ist that may contribute to the cause and pathogenesis of fragmented coronoi d process in Rottweilers. Sample Population-Paired elbow joints from 13 Rottweilers and 14 Greyhounds . Procedure-Elbow joints were radiographically scored on the basis of severit y of osteoarthritic lesions. The articular contour of each ulnar trochlear notch was digitized. The radius of curvature at defined points along the ul nar trochlear notch was compared between breeds. Results-Radius of curvature of the ulnar trochlear notch was not a constant function of are length in either breed but had a consistent characteristic appearance in both breeds. Radius of curvature was greatest at each end of the ulnar trochlear notch and had 2 peaks in the midportion of the notch i n both breeds. These peaks occurred farther distally in the notch and were larger in Rottweiler ulnae than Greyhound ulnae. A significant difference i n mean radius of curvature was detected between breeds at these peaks. Grey hounds had significantly greater mean radius of curvature at the end of the medial coronoid process, compared with Rottweilers. Conclusions and Clinical Relevance Radius of curvature of the ulnar trochle ar notch is a complex function of are length in Rottweilers and Greyhounds. The waveform has a consistent characteristic appearance in both breeds. Al though significant differences were identified between breeds, associations between these differences and cause or pathogenesis of fragmented coronoid process in Rottweilers were not apparent.