Microcomputed tomographic analysis of the ulnar trochlear notch in medium- and large-breed canine cadavers with and without medial coronoid disease.

Medial coronoid disease (MCD) is a common disease often associated with thoracic limb lameness in medium- and large-breed dogs. The term MCD includes subchondral changes of the medial coronoid process (MCP), as well as pathologies of both cartilaginous surfaces. As there are only a few comprehensive and detailed studies on the trabecular structure of the medial coronoid, the goal of this study was to compare the trabecular structure of the ulnar trochlear notch of canine cadavers with and without MCD using different micro-computed tomographic (micro-CT) parameters. Fifty-eight elbow joints from 29 canine cadavers of MCD-predisposed and non-predisposed breeds (control group) were examined radiographically, macroscopically and by microcomputed tomography. The study included elbow joints of eight Labrador Retrievers (21.6-37 kg), seven Golden Retrievers (26.3-42 kg), seven Bernese Mountain dogs (31-47 kg) and seven dogs of non-predisposed breeds (19.7-52 kg) (control group). The final diagnosis of MCD was based on necropsy and micro-computed tomographic examinations. Micro-CT examinations were performed using XtremeCT II (Scanco Medical, Zurich, Switzerland) and the following parameters were examined: bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), trabecular number (Tb.N), connectivity density (Conn.D) and degree of anisotropy (DA). Twenty-four elbows of 44 elbows of the predisposed breeds (Labrador Retrievers, Golden Retrievers Bernese Mountain dogs) showed subchondral changes and lesions of the cartilage surfaces. The result of this study is a higher density (BV/TV) of the trabecular bone of the ulnar trochlear notch in elbows affected by MCD compared to the control group. The increased density due to trabecular reconstruction in the ulnar trochlear notch is likely the result of selectively increased loading during life.