Perinatal and gestational factors associated with Pavlik harness outcomes in developmental dysplasia of the hip: a retrospective cohort study.

Introduction: Perinatal and gestational factors contribute to both the pathogenesis and prognosis of developmental dysplasia of the hip (DDH). However, data regarding the association between these factors and Pavlik harness treatment outcomes remain scarce. This study aimed to assess the associations between perinatal/gestational factors and Pavlik harness treatment outcomes, and to preliminarily establish a predictive model incorporating these factors to inform early treatment optimization for DDH. Methods: Perinatal and gestational data, along with treatment outcomes, were collected from children diagnosed with DDH through screening in Tianjin, China, between 2013 and 2023, who were treated with the Pavlik harness. All analyses were performed at the patient level. A multivariable logistic regression model was developed to identify perinatal and gestational factors independently associated with treatment outcomes. Receiver operating characteristic (ROC) curves were constructed to evaluate the model's discriminative ability, and a nomogram was developed for outcome prediction. Internal validation was performed using bootstrap resampling with 200 iterations. Results: Among 792 children (910 hips) included, low Graf classification, higher maternal education level, cephalic intrauterine position, parity > 1, maternal combined vitamin A and D supplementation during pregnancy and regular maternal milk consumption during pregnancy were significantly associated with higher treatment success rates. The overall prediction model, integrating Graf classification with the five perinatal and gestational factors, achieved a bootstrap-corrected C-index of 0.781, with significantly higher diagnostic accuracy than any single factor or alternative combination (AUC = 0.796, Conclusion: Several perinatal and gestational factors were independently associated with Pavlik harness treatment outcomes in DDH. The nomograms developed in this study may serve as preliminary decision-support tools for predicting treatment outcomes and facilitating the selection of more appropriate clinical management strategies, particularly for Graf types IIc and D/III. Given the observational study design, these findings should be interpreted as exploratory associations rather than causal determinants, and external validation is warranted before clinical implementation.