Reliability of a New Radiological Parameter Named the Modified Tönnis Angle for the Evaluation of Acetabular Dysplasia in Adults

Abstract

Objectives: To evaluate the reliability of Tönnis angle and modified Tönnis angle on pelvic radiographs in adults. Methods: Conventional anterior-posterior pelvic radiographs of patients were selected from the picture archiving communication system (PACS) in the department of medical radiology of the Second Hospital of Shandong University. Tönnis angle and modified Tönnis angle were measured. All measurements were performed by two experienced observers who worked independently of each other. These measurements were performed again after one month. They were performed digitally using tools of the PACS. Reliability of Tönnis angle and modified Tönnis angle was assessed by intraclass correlation coefficients and Bland and Altman plot.