Hip sonography: thirty-four years of experience in Italy

Abstract

This paper provides a review of the years of experience of hip sonography since the first ultrasound (US) course in Italy in 1987. Clinical and US findings were correlated in 1,000 newborns examined consecutively in a study in 1991. Developmental dysplasia of the hip (DDH) was present even in the absence of clinical signs, including the Ortolani sign. The percentage of US diagnosis of DDH in newborns was 2.8%, while instability according to the Ortolani test was present in 0.75%. After recommendations from the American Academy of Pediatrics against universal US screening, early diagnosis decreased from 74.4% in the period 1992–2002 (43,418 hips examined) to 52.7% in 2013–2014 (5,598 hips examined). In order to answer the question of whether early treatment of DDH has better outcomes, the acetabulum maturation was studied in 93 type III hips. The statistical analysis showed a strong dependency (P < 0.001) between the alpha-angle gain and the age at which treatment was started. The first 2 weeks of life is the optimum time for early diagnosis and treatment; after 6 weeks of life, treatment is less effective and the results are less predictable. Furthermore, the role of the labrum and its morphological changes was analyzed in 86 unstable dysplastic hips (13 type D, 49 type III and 24 type IV) in patients with an average age of 53 days (range 1–134 days) at DDH diagnosis and the beginning of treatment. The labrum was never inverted and underwent a statistically significant increase in echogenicity and dimensions with a frequency of 97% and 96% respectively, suggesting the labrum’s stabilizing role. Abnormal findings such as in achondroplasia, cleidocranial dysplasia, other rare osteochondrodysplasias and in coxa vara are underlined. Uncommon findings such as incomplete acetabular bony rim and eccentric position of the femoral head nucleus are also described.