Primary flexor enthesopathy of the canine elbow: imaging and arthroscopic findings in eight dogs with discrete radiographic changes.

OBJECTIVE To describe the radiographic, ultrasonographic, computed tomography (CT), magnetic resonance imaging (MRI), and arthroscopic findings in eight dogs with elbow lameness caused by primary flexor enthesopathy. STUDY DESIGN Clinical study. ANIMALS Eight client-owned dogs. METHODS In all dogs, lameness was localized to the elbow by clinical examination. Radiographic examination, ultrasound, CT and MRI were performed prior to arthroscopy. In seven dogs, surgical treatment and subsequent histopathology were performed. RESULTS Primary enthesopathy of the medial epicondyle was diagnosed in eight dogs (13 joints) by combining the minimal radiographic changes with specific ultrasonographic, CT, MRI and arthroscopic findings at the medial epicondyle. In all joints, any other pathology could be excluded. Histopathology of the affected tissue revealed degeneration and metaplasia in the flexor muscles. CONCLUSIONS Primary flexor enthesopathy at the medial epicondyle is an unrecognized condition and is a possible cause of elbow lameness in the dog. Diagnosis is based on specific imaging and arthroscopic findings. CLINICAL RELEVANCE The most important cause of elbow lameness in dogs is medial coronoid disease. Often this condition presents with minimal radiographic and arthroscopic changes. In these cases, primary enthesopathy of the medial epicondyle should be considered as a differential diagnosis, in order to make the correct treatment decision.