D-line is the diagonal line drawn 45° from the junction of H-line and P-line. P-line is Perkin’s line, drawn perpendicular to the H-line at the superolateral margin of the acetabulum. 18 H-line is Hilgenreiner’s line, drawn through the top of the triradiate cartilages bilaterally. International Hip Dysplasia Institute classification for severity of developmental dysplasia of the hip (not requiring the presence of an ossific nuclei). The priority is differentiating between neonatal hip instability, acetabular dysplasia and subluxation or dislocation of the hip, as severity of involvement (Figure 1) determines the treatment required to obtain a concentric reduction.įigure 1. To properly triage the referral, access to the radiological images is required to ensure that the radiological interpretation is correctĪdapted from Department of Orthopaedics, Referral guidelines: Developmental dysplasia of the hip – DDH, Melbourne, Vic: Royal Children’s Hospital, 2020, Available at.Surveillance anteroposterior pelvis X-ray at 12 months of age if child previously investigated for DDH (because of incidence of late‑presenting DDH).Screening ultrasonography if risk factors present in child aged 6 months.Hip ultrasonography if aged ≤6 months (paediatric ultrasonography service if possible).Hip examination to check for instability with Barlow’s and Ortolani’s tests.Intrauterine packaging deformities (eg plagiocephaly, foot deformities or torticollis).Developmental dysplasia of the hip: Referral guidelines 6 This, combined with an understanding of the risk factors, will help in the early diagnosis and management of children with DDH (Table 1). Establishing the diagnosisĪs previously stated by Williams, ‘repeated, carefully performed clinical examinations of the paediatric hip from newborn to walking age remain the best method for early detection of DDH’. The emphasis of this article is on the management of DDH in infancy and the early years management of DDH during adolescence and adulthood is not included. 4ĭDH and its sequelae continue to have a major impact on healthcare, with the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) reporting that nearly 7% of total hip replacements in Australia are directly attributable to DDH. 3 Management of this wide continuum of pathology requires careful consideration, because management varies greatly as the age of the child increases. Presentations can vary from an infant born with a fixed, irreducible dislocated hip through to mild acetabular dysplasia only diagnosed in adulthood. The wide spectrum of pathology affecting this process is named developmental dysplasia of the hip (DDH). Postnatally, the sphericity of the femoral head and deepening of the acetabulum are expected to increase progressively through childhood. Teleologically, it is possible that a temporarily increased hip range of motion in the third trimester is required to accommodate the lower limb within the limited intrauterine space. This trend reverses after birth, with the acetabulum deepening, femoral head coverage increasing and hip morphology improving. The embryonic acetabulum begins as a deeply set cavity that almost entirely encloses the femoral head but gradually becomes shallower as birth approaches. The human acetabulum is shallower at birth than at any other time during development.

Normal hip frogleg xray