Background Developmental dysplasia of the hip (DDH) diagnosed in early infancy (<10 weeks of age) is usually successfully treated with abduction harnessing. Later diagnosis carries an increasing risk of need for surgical treatment and poorer outcomes. Methods For all children born in Scotland 1997/98 to 2010/11, we compared the risk of surgery for DDH by age three years. We compared risks for children born before and after implementation of improved DDH detection pathways. Under usual care in Scotland, all babies undergo clinical examination of the hip (Ortolani/Barlow tests) by a non-specialist examiner as part of the newborn and 6-8 week examinations. Babies with positive examination findings and those at higher risk due to DDH risk factors are referred for further investigation. Two areas of Scotland (NHS Lothian and Fife) independently introduced improved DDH detection pathways between 2002/03 and 2004/05, employing a specialist physiotherapist and paediatrician respectively to increase awareness of DDH, train staff undertaking newborn physical examinations in hip examination, and improve access to expert hip examination and ultrasound scans. We used a logistic regression model of first surgery for DDH by age 3 as recorded in national hospital discharge records on an area by period interaction to estimate the difference-in-difference. Findings Among 777,375 live births in Scotland in 1997/98 to 2010/11, 918 children underwent first surgery for DDH by age three years; 1.18 (95% CI 1.11-1.26) per 1,000 live births. The risk of surgery for babies born in the post-introduction period (2005/06-2010/11) compared to the pre-introduction period (1997/98-2001/02) halved in the intervention areas (NHS Lothian and Fife combined) but remained unchanged elsewhere in Scotland. The ratio for the difference in change of risk was 0.46 (95% CI 0.31-0.70). Interpretation Implementation of enhanced DDH detection pathways can substantially reduce late diagnosis of DDH and associated requirement for surgical correction. Current models of care based on non-specialist clinical hip examination are associated with unacceptably high rates of late DDH diagnosis.