Predictive value of post-reduction gadolinium-enhanced magnetic resonance imaging in detecting avascular necrosis after closed and open reduction for developmental dysplasia: A minimum 5-year follow-up study

Purpose: We aimed to investigate whether globally decreased enhancement on post-reduction gadolinium-enhanced magnetic resonance imaging can predict avascular necrosis after open or closed reduction for developmental dysplasia of the hip. Methods: We retrospectively analyzed 83 patients (94 hips) who underwent open or closed reduction, with a minimum 5-year follow-up. There were 79 females (84%) with a median age of 7.2 months (interquartile range, 4.8–12). Femoral head enhancement on post-reduction gadolinium-enhanced magnetic resonance imaging was evaluated, and the most recent radiographs were graded using the Kalamchi and MacEwen avascular necrosis classification. Logistic regression was employed to identify predictors of avascular necrosis, and diagnostic performance was calculated. Results: Of the 94 hips, 51 (54%) exhibited normal enhancement, 20 (21%) had asymmetric enhancement, 11 (12%) had focal decreased enhancement, and 12 (13%) showed global decreased enhancement. At the final follow-up, 63 hips (67%) had no avascular necrosis, and 31 (33%) developed avascular necrosis: 13 (14%) Grade 2, 7 (7%) Grade 3, and 11 (12%) Grade 4 severe avascular necrosis. Multivariate analysis revealed no significant association between globally decreased enhancement, age, type of reduction, or abduction angle with the development of any avascular necrosis or severe avascular necrosis. Sensitivity was low for hips with any avascular necrosis (13%) and severe avascular necrosis (36%), while specificity was 87% and 90%, respectively. Conclusions: Globally decreased enhancement on post-reduction gadolinium-enhanced magnetic resonance imaging does not necessarily indicate long-term avascular necrosis development following closed or open reduction for developmental dysplasia of the hip. Treatment decisions should not solely rely on this finding. Further research is needed to improve imaging accuracy and assess whether modifying treatment in response to enhancement patterns can reduce avascular necrosis risk. Level of Evidence: Diagnostic, level 3 retrospective cohort.