A clinical study of hip arthrography combined with MRI to assess acetabular development after early treatment of DDH in children

A clinical study of hip arthrography combined with MRI to assess acetabular development after early treatment of DDH in childrenBackground： Developmental dysplasia of the hip (DDH) is one of the most common skeletal muscle diseases in children. Even after successful early conservative treatment, there is a high risk of residual acetabular dysplasia (RAD) in the affected hip, which may require secondary surgery. The current study suggests several prediction indexes for clinical reference, but if the hip with the poorer future outcome can be identified at an earlier stage by several prediction indexes, and thus a second surgery can be performed earlier, the greater the developmental potential left for the child.Purpose： The purpose of this study was to find a more stable and accurate early RAD prediction model by hip arthrography combined with MRI and a combination of multiple indexes for the prediction of RAD after early treatment.Patients and Methods： From December 2020 to December 2021,13 children who met the inclusion criteria were included, with a total of 21 hips ( 8 cases of bilateral DDH ). According to the exclusion criteria, the remaining 15 hips were statistically analyzed. The acetabular cartilaginous angle (ACA) and femoral head coverage (FHC) were measured on the initial closed reduction arthrography X-ray, and the cartilaginous acetabular index (CAI) and cartilaginous center-edge angle (CCE) were measured on the MRI after the initial closed reduction. The AI in the 1-year follow-up X-ray was compared with the corresponding normal AI range in Chinese children and divided into satisfactory and unsatisfactory groups. ICC was used to assess intra-observer and inter-observer consistency for the same index. Independent samples t-test and χ 2 test were used to compare the two groups for measurement and count data, respectively, and differences were considered statistically significant at P < 0.05. The receiver operating characteristic ( ROC ) curve was drawn to evaluate the diagnostic efficacy of CAI, CCE, ACA, FHC, and different combinations of each index on prognosis, and the area under the curve ( AUC ) was calculated.Results： The ROC curve of each early prediction index showed that the AUC values of CAI and CCE were between 0.5 and 0.7 when using a single cartilaginous index to evaluate short-term prognosis, which was at a low level; The AUC values of ACA and FHC were between 0.7 and 0.9, which was in medium level. The combination of multiple indexes can improve the diagnostic efficacy, and in the analysis of the combination of both indexes, CAI combined with ACA had the highest AUC value of 0.893, which was at a medium level. When the three indexes were combined, the CAI+CCE+ACA combination had the highest AUC value of 0.946, achieving a high level. The maximum AUC value of 0.982 was obtained when all four indexes were combined, achieving a high level of diagnostic efficacy.Conclusion： The combination of multiple indexes and multiple imaging examinations can form a comprehensive and systematic prediction model, which can significantly improve the accuracy of single index prediction, and our validated "ACA+FHC+CAI+CCE" is a reliable prediction model. The model can predict early acetabular developmental outcomes after closed reduction and provide guidance for possible secondary orthopedic surgery

儿童发育性髋关节发育不良早期治疗后髋臼发育评估：髋关节造影联合磁共振成像的临床研究
背景：发育性髋关节发育不良（Developmental Dysplasia of the Hip，DDH）是儿童最常见的骨骼肌疾病之一。即使早期保守治疗成功，受累髋关节仍存在较高的残留髋臼发育不良（Residual Acetabular Dysplasia，RAD）风险，可能需要二次手术。目前研究提出了若干预测指标供临床参考，但若能通过多预测指标更早识别预后较差的髋关节并提前实施二次手术，将为儿童保留更大的发育潜力。
目的：本研究旨在通过髋关节造影联合磁共振成像（Magnetic Resonance Imaging，MRI）并结合多指标，建立更稳定、准确的早期RAD预测模型，以评估DDH早期治疗后的RAD情况。
患者与方法：2020年12月至2021年12月期间，纳入13例符合纳入标准的儿童，共涉及21个髋关节（其中8例为双侧DDH）。根据排除标准，最终对15个髋关节进行统计分析。在初始闭合复位造影X线片上测量髋臼软骨角（Acetabular Cartilaginous Angle，ACA）和股骨头覆盖率（Femoral Head Coverage，FHC）；在初始闭合复位后的MRI上测量软骨性髋臼指数（Cartilaginous Acetabular Index，CAI）和软骨性中心边缘角（Cartilaginous Center-Edge Angle，CCE）。将1年随访X线片中的髋臼指数（AI）与中国儿童相应正常AI范围比较，分为满意组和不满意组。采用组内相关系数（ICC）评估同一指标的观察者内及观察者间一致性。计量资料和计数资料分别采用独立样本t检验和χ²检验，差异有统计学意义的标准为P＜0.05。绘制受试者工作特征（Receiver Operating Characteristic，ROC）曲线以评估CAI、CCE、ACA、FHC及各指标不同组合对预后的诊断效能，并计算曲线下面积（Area Under the Curve，AUC）。
结果：各早期预测指标的ROC曲线显示，单一软骨指标评估短期预后时，CAI和CCE的AUC值介于0.5~0.7之间，处于较低水平；ACA和FHC的AUC值介于0.7~0.9之间，处于中等水平。多指标联合可提高诊断效能：双指标组合分析中，CAI联合ACA的AUC值最高（0.893），处于中等水平；三指标组合中，CAI+CCE+ACA组合的AUC值最高（0.946），达到较高水平；四指标联合时AUC值最高（0.982），诊断效能达较高水平。
结论：多指标联合及多影像学检查相结合可形成全面系统的预测模型，显著提高单一指标预测的准确性，本研究验证的“ACA+FHC+CAI+CCE”是一个可靠的预测模型。该模型可预测闭合复位后早期髋臼发育结局，为可能的二次矫形手术提供指导。