Hip arthrogram in developmental dysplasia of the hip: A review.

The hip arthrogram is an invaluable tool in the management of developmental dysplasia of the hip (DDH). The pathological findings seen on arthrogram in hips with DDH were first described by Severin and Leveuf in the 1940s. These findings were later shown to correlate with findings at open reduction, and in more recent years, on magnetic resonance imaging (MRI) studies as well. The medial sub-adductor technique is most commonly used to perform hip arthrograms. The neutral antero-posterior, frog leg and Salter position views tend to be the most informative; however, arthrography also provides the opportunity for dynamic assessment and stress views. The structures that can be assessed in detail during hip arthrograms include the cartilaginous femoral head; the labrum, limbus and neolimbus; the bony and cartilaginous acetabular roof; intra-capsular structures like pulvinar, ligamentum teres and transverse acetabular ligament; and extra-capsular structures like the psoas shadow and capsular constriction. Measurements made on arthrogram, such as medial dye pool and femoral head coverage, help guide intra-operative decision-making and can have prognostic value as well. While some authors propose that the best indicator of outcome is the quality of the initial reduction, others have demonstrated that outcomes cannot be predicted accurately based on initial post-reduction arthrograms due to the phenomenon of "docking", and that interval arthrograms and/or MRI studies can help in decision making. Finally, it must be remembered that arthrographic findings should be interpreted in conjunction with clinical findings, with the aim being to achieve a reduction that is both safe and stable. This review paper summarises the existing evidence on hip arthrography for DDH.