A limping child

A 15 month old girl was referred to the orthopaedics department by her general practitioner with an abnormal gait and a tendency to fall over more than her peers. There was no history of trauma or family history of note, and she was otherwise well. She was born by uncomplicated spontaneous vaginal delivery at term and began walking independently aged 13 months. The midwife had commented to the mother during neonatal examination that the left hip was “a bit clicky,” but this had not been investigated further. On examination she walked, apparently pain free, with a left sided lurch. Her left leg was 2 cm shorter than her right leg. Hip instability tests were normal. The general range of motion in the left hip was good, but abduction was limited and the telescope test was positive. A plain radiograph of the pelvis was obtained (fig 1⇓). ### 1. What is the diagnosis? #### Short answer Left sided developmental dysplasia of the hip. #### Discussion Developmental dysplasia of the hip (DDH) covers a spectrum of disorders, from mild dysplasia of the acetabulum without displacement to subluxation, dislocation, and aplasia of the joint.1 2 3 4 The incidence of true DDH is probably 1.3-5 per 1000 live births, but it depends on the definition used and the population studied, although evidence suggests that neonatal hip instability is found in 34-55 per 1000 live births.5 6 7 The features of DDH develop during the antenatal period and the early years of life and have been associated with several factors. Rarely, “teratological” hip dysplasia and dislocation occur in utero, but most children have only subtle signs …