In this prospective study, medial humeral epicondylitis was characterized based on anatomic, radiographic, and histologic observations in 60 European shorthair cats that died (or were euthanized) for medical reasons. Elbow instability was not noted in any cats. Radiographs of both elbows were taken using extended craniocaudal and extended and flexed mediolateral projections. Histologic samples from normal elbows and those with new bone formation at the medial epicondyle were compared. Radiographic evidence of medial humeral epicondylitis including chronic degeneration, mineralization, and metaplastic bone formation were noted in 6 cats (10%); 2 had histologic evidence of ulnar nerve displacement and epineural fibrosis. Results suggested that medial humeral epicondylitis is common in cats and has potential clinical sequelae. Active pronation and supination are important movements in cats, especially for climbing and hunting. Whether this predisposes cats to epicondylitis is unknown. Early stage epicondylitis may be overlooked in cats, particularly in the absence of soft tissue mineralization on radiographs.
CommentaryThis prospective study examined 60 deceased cats with no history of orthopedic disease. Radiographs were taken of the elbows and intricate histologic evaluation was performed. In more severe cases of medial epicondylitis, cartilage defects, local mineralization and thickening of the joint capsule, and compression with degenerative changes in the ulnar nerve were seen. Inflammation was not seen, which is consistent with the human version (ie, tennis elbow), in which inflammation is only present in the early stage. This analysis by the University of Zurich lends more precise information on the pathology of elbow arthritis in cats. The effect of joint disease on the ulnar nerve is fascinating. Early diagnosis and treatment with disease-modifying agents, weight loss, and NSAIDs would be beneficial to these suffering patients.—Jonathan Miller, DVM, MS, DACVS
SourceMedial humeral epicondylitis in cats. Streubel R, Geyer H, Montavon PM. VET SURG 41:795-802, 2012.