Relative Risk and Incidence for Developmental Dysplasia of the Hip

Abstract

Objective: To determine the incidence and associated risk factors of developmental dysplasia of the hip (DDH) in a modern population without universal screening.

Study design: Children with DDH were identified from the Manitoba Centre for Health Policy's Data Repository by the use of International Classification of Diseases diagnosis codes as well as physician billing tariffs for surgical procedures for DDH for all children born between 1995 and 2012. To identify the outpatient-treated patients, ultrasound scans and radiographic imaging for DDH were reviewed for 2004-2012. Overall incidence was calculated on the basis of birth rate for the province per year. Relative risks of sex, first born, breech position, clubfoot deformity, multiple gestations, as well as regional health areas were analyzed with χ² tests.

Results: We identified 1716 cases of DDH of 258 499 newborns. The incidence of DDH was calculated at 6.6/1000 newborns. Late-presenting DDH was detected in 2.2/1000 newborns. Female first-born children, clubfoot deformity, and breech position were associated significantly with an increased risk. Children with DDH born in rural areas of the Northern and Central part of Manitoba presented at a later age than those who are born in the urban areas (P < .0001) CONCLUSION: This study shows the need for improved early detection and awareness at well-baby clinics of risk factors and regional differences for DDH.

Keywords: Manitoba; hip dysplasia; late-presentation; risk factors.