Background: Axial imaging is typically obtained following operative reduction of developmental dysplasia of the hip (DDH) to confirm a concentric reduction. Although the utility of axial imaging has been studied following the index reduction, its value following spica cast exchange remains unclear. Methods: This single-center study included all children 2 years or younger with idiopathic DDH who underwent closed or open reduction between 2012 and 2023. Patients with concurrent osteotomies or dysplasia secondary to syndromic/neuromuscular causes were excluded. Institutional protocol during this period consisted of 3 months of immobilization with a spica cast exchange at 6 weeks for all closed or medial open reductions. Axial imaging (CT or MRI) was typically obtained after both the index procedure and cast exchange to confirm reduction. A retrospective review was conducted to assess how often axial imaging directly altered clinical management, defined as an unplanned return to the operating room or a documented change in management based on imaging findings per the treating surgeon’s notes. Minimum follow-up was 1 year. Descriptive statistics were used to summarize patient characteristics and arthrogram findings. Results: The cohort included 91 patients (124 hips): 92 (74%) hips underwent closed reduction, and 32 (26%) underwent open reduction. The median age at index reduction was 7.7 months, with 52% (n=47/91) above 6 months old. Of those with preoperative radiographs (n=98), most hips were IHDI grade 3 (29%, n=27) or 4 (39%, n=38). Axial imaging changed management in 3% of hips after the index reduction (4/92 closed reductions, 0/32 open reductions). Among 124 hips receiving axial imaging at cast exchange (92=MRI, 32=CT), only 1 hip was dislocated (<1%). Analysis of a separate cohort of 12 hips that did not receive axial imaging at cast exchange suggests that an adequate arthrogram (no medial dye pool and deep concentric reduction) is sufficient to confirm reduction. Conclusions: Axial imaging at the time of spica cast exchange rarely alters clinical management and should not be routinely obtained unless otherwise indicated by a concerning intraoperative arthrogram. Level of Evidence: Level IV—retrospective case series.
Beck et al. (Mon,) studied this question.