Post-traumatic disturbance of the epiphysis of the humeral trochlea: a spectrum of pathology

BACKGROUND: Hegemann disease and fishtail deformity are classified as growth disturbances in the physeal plate of the humeral trochlea. It is questionable if these 2 diseases should be considered as 2 distinct conditions. The aims of this study are to (1) point out similarities between both conditions, (2) discuss etiology, and (3) provide diagnostic tools. METHODS: In a multicenter prospective cohort study, 19 patients with growth disturbance of the humeral trochlea were included. Assessment consisted of a detailed history, physical examination, and standard radiographs in 2 directions. The radiographs were evaluated for skeletal age, carrying angles, and trochlear notch angles. Statistical analysis was performed using Stata. RESULTS: A total of 19 patients were included: 2 males (11%) and 17 females (89%). The mean age of the patients was 12.8 years. In 17 patients (89%), a traumatic injury of the elbow was reported, before presentation. Decreased trochlear notch angle (<104°) was seen in 16 patients (84%). Accelerated closure of the growth plate of the affected elbow was seen in all skeletally immature patients. CONCLUSIONS: The main risk factor for both Hegemann disease and fishtail deformity is an injury of the elbow with open growth plates. Imaging studies support the hypothesis that both diseases are likely to be a continuum of the same process. Therefore, we propose to use 1 nomenclature for this pathologic process: post-traumatic disturbance of the epiphysis of the humeral trochlea.