The acetabulum in Perthes’ disease: Inter-observer agreement and reliability of radiographic measurements

摘要

Background and purpose — Perthes’ disease leads to radiographic changes in both the femoral head and the acetabulum. We investigated the inter-observer agreement and reliability of 4 radiographic measurements assessing the acetabular changes. Patients and methods — We included 123 children with unilateral involvement, femoral head necrosis of more than 50%, and age at diagnosis of 6 years or older. Radiographs were taken at onset, and 1 year and 5 years after diagnosis. Sharp’s angle, acetabular depth-width ratio (ADR), lateral acetabular inclination (LAI), and acetabular retroversion (ischial spine sign, ISS) were measured by 3 observers. Before measuring, 2 of the observers had a consensus meeting. Results — We found good agreement and moderate to excellent reliability for Sharp’s angle for all observers (intra-class correlation coefficient (ICC) 0.80 with consensus, ICC = 0.46–0.57 without consensus). There was good agreement and substantial reliability for ADR between the observers who had had a con...