Hip dysplasia and ultrasound imaging of whole populations: the precautionary principle revisited

Screening for developmental hip disorders has been with us for almost 40 years. Twenty years ago Cliff Roberton famously called it a “mess”.¹ The paper by Roovers et al² published in this issue reports the findings of an observational study to determine whether a strategy of universal ultrasound screening carried out after the newborn period is “more effective” than a strategy based on clinical examination alone. Before considering the implications of this report for policy and practice, it is worth rehearsing some of the challenges facing those who have sought to evaluate this “mess” over the last 40 years.

Developmental dysplasia of the hip (DDH) refers to a spectrum of developmental hip disorders including partial or complete displacement of the femoral head from the acetabulum—that is, developmental displacement of the hip, previously called congenital dislocation of the hip (CDH). Ultrasound imaging of the largely cartilaginous newborn hip, first introduced in the 1980s and pioneered by Graf, has contributed to a paradigm shift in what we mean by CDH. Neonatal hip instability has become synonymous with the outcome it was meant to signal, and dysplastic or shallow hips in the newborn have been added to the disorders for which screening is considered desirable, despite there being only limited understanding of their significance for later hip development.³

When introduced in the 1960s, there was an expectation that early recognition through clinical screening combined with abduction splinting would prevent impaired hip growth and development, serious abnormalities of gait, and premature degenerative changes in the hip joint. To …