Purpose or Case Report: The fishtail deformity of the distal humerus is a rare entity that most often develops as late sequela of a pediatric elbow fracture. The observed morphologic changes that define this diagnosis have been attributed to vascular compromise of the lateral trochlea and subsequent resorption or failure of development of the trochlear ossification center (dependent upon the skeletal maturity of the patient at time of initial injury). The purpose of this exhibit is to demonstrate the imaging features that will allow radiologists to confidently diagnose a fishtail deformity of the distal humerus and to understand the pathogenesis behind the morphologic appearance. We will also discuss prognosis and management, knowledge that will allow the radiologist to be of additional value in multidisciplinary discussions.
Methods & Materials: The imaging evolution of the developing fishtail deformity will be demonstrated via several patient cases starting from initial injury with follow up through the development of the fishtail deformity. Multiple imaging modalities will be utilized to demonstrate the findings. A literature review was also performed to describe the pathogenesis that results in the development of the fishtail deformity.
Results: This educational exhibit will provide a description of the specific imaging findings of the fishtail deformity of the distal humerus on multiple modalities (radiographs, CT, MRI) using recent cases from our institution. We will identify the types of trauma that can predispose a patient to develop this deformity, the at-risk patient population, and the pathogenesis behind the morphologic changes that occur. We will also describe the common symptomatology with which these patients present, prognosis, and the most commonly employed treatment options.
Conclusions: Early identification of a fishtail deformity of the distal humerus by the radiologist can ensure appropriate management is sought prior to a patient sustaining irrevocable damage to the elbow joint. An understanding of the pathogenesis behind the development of the deformity can aid the radiologist in identifying at-risk patients and help guide image interpretation.