Arthroscopic findings in 32 joints affected by severe elbow incongruity with concomitant fragmented medial coronoid process.

OBJECTIVE To report arthroscopic findings in dogs with severe elbow incongruity combined with fragmented medial coronoid process (FCP) and compare these findings in normal joints and congruent joints affected by FCP. STUDY DESIGN Clinical study. ANIMALS Dogs with elbow lameness (n = 40) and purpose bred dogs (5; controls). MATERIALS AND METHODS Arthroscopic features of 32 severely incongruent joints with concomitant FCP were compared with 32 congruent elbow joints affected with FCP and 10 normal joints. A radioulnar step of ≥ 3 mm on radiographs and computed tomography (CT) scans was the selection criterion for a severely incongruent joint. Intraarticular structures were visually assessed at various sites within the joint. Regions of interest were: the radioulnar transition, humeroradial and humeroulnar joint space, trochlear notch, primary and secondary lesions of the medial coronoid process, and radial head. RESULTS Incongruent joints had a radioulnar step and changes at the cartilage in the center of the trochlear notch, an irregular radioulnar transition, and an abnormal surface of the radial head. Coronoid pathology was present in every pathologic joint. CONCLUSION Arthroscopy allowed detection of several features that were signs or consequences of severe elbow incongruity or accompanying inflammation. After a prominent radioulnar step, cartilage changes involving the radial head and trochlear notch were most frequently seen.