The Value of Axial Imaging to Check Reduction after Anterior Approach Open Reduction for Developmental Dysplasia of the Hip

Abstract

Background: There are still many controversies regarding the diagnosis and management of developmental dysplasia of the hip (DDH). Axial imaging is routinely used after closed or open reduction to confirm reduction has occurred. In this study, we aimed to determine the rate of early re-dislocation or failure of reduction after anterior approach open reduction (AOR), to establish whether there is a true need for routinely performing post-operative axial imaging.

Methods: We retrospectively reviewed radiographs, operation notes and post-operative CT scan images of our AOR cases from September 2018 to June 2020. The CT scan images were reviewed to check the post-operative reduction and congruency. The ‘posterior neckline’ and the ‘modified Shenton line’ were used to assess reduction. The related literature was also reviewed.

Results: Thirty patients were included. The post-operative CT scans confirmed that all cases had reduced congruent hips. The CT scans did not change future treatment plans for any patient in this cohort and did not predict late re-dislocation.

Conclusions: The rate of early re-dislocation or failure of reduction after AOR was negligible. Traditional routine axial imaging after this operation is therefore unjustified and has no value in predicting possible late re-dislocations. It also comes at the cost of extra radiation to the child and expense for the health system. We recommend stopping the routine use of post-operative axial imaging and using it selectively for specific indications, including teratologic and neuromuscular hips, bilateral DDH, and after revision surgery, in addition to closed reductions and medial approach open reduction.