Background: This study aimed to compare the early outcomes between closed reduction (CR) and open reduction (OR) in children aged 6-24 months with developmental dysplasia of the hip (DDH) who could be reduced safely and stably by the closed method.Methods: We retrospectively reviewed the medical records of 77 patients who underwent CR or OR treatment for DDH from August 2012 to October 2017. Fifty-one patients (56 hips) underwent CR, while 26 (29 hips) underwent OR. The demographic data, International Hip Dysplasia Institute classi cation, and acetabular index (AI) before reduction were analysed. The centre-edge angle (CEA), AI, Alsberg angle (AA), Reimer's migration index (RMI), and height-to-width index (HWI) of the epiphysis were compared between the CR and OR groups at the nal follow-up. The percentages of avascular necrosis (AVN), residual acetabular dysplasia (RAD), HWI < 0.357, RMI > 33%, AA > 81˚, and coxa magna > 15% of the normal side were calculated.Results: At the nal follow up, the mean AA in the CR and OR groups were 77.66˚ (60˚-89˚) and 81.97( 73˚-91˚) (p=0.001), respectively, and there were 32.14% and 58.62% of the hips with an AA > 81( p=0.019). The frequency of coxa magna > 15% of the normal side was higher in the OR group (60.9%) than in the CR group (6.5%) (p<0.001). There was no difference in the improvement of AI, CEA, HWI, and RMI at the nal follow-up. The percentages of RAD, HWI < 0.357, RMI > 33%, and AVN were not statistically different. Conclusion:In children aged 6-24 months with DDH, if a stable and safe CR can be obtained but with a widening joint space, an OR may not bene t acetabular remodelling more than a CR procedure, and thus, CR should be attempted.

Objective For pediatric lateral condylar fractures (LCFs) of the humerus, it is often hard to determine the stability of the fracture based on the Song classification, especially for those categorized as Song stages 2 and 3. This study aims to define the characteristics of cartilage injury and assess the stability of LCFs classified as Song stages 2 and 3 on post‐traumatic magnetic resonance imaging (MRI). Methods This was a retrospective study based on imaging data, conducted with a short follow‐up period. From January 2016 to May 2019, data of all patients with Song 2 and Song 3 LCFs treated at two institutions were collected. Based on the inclusion criteria, a total of 62 patients with Song stage 2/3 LCF were included. All radiographs were selected for observation and classification for comparison by two observers, both experienced pediatric orthopedic surgeons. MRIs scans for comparison were analyzed in three consecutive coronal sections and cross‐sections. Patients were treated conservatively with casting or surgically with closed reduction and percutaneous pinning (CRPP). Results Altogether 62 cases between 1.5 to 9 years old were included. Reliability analysis revealed poor, moderate, or good agreement between the two observers (range, 0.149–0.633). Both observers showed moderate or good consistency (range, 0.413–0.611). Among the 62 patients diagnosed with Song stages 2 and 3 fractures on initial radiographs, only two patients (3%) had complete fractures with complete disruption of the cartilage hinge as seen on MRI. The hinge was generally located in the posterior‐inferior region of the distal humeral cartilage as indicated on MRI. There was no significant difference between Song stages 2 and 3 with regard to ratio of hinge to total values in any cross‐sections, nor was there any significant difference in the completeness of the coronal sections ( P > 0.05). Of the 62 patients treated, 50 were managed conservatively with casting and 12 underwent CRPP. Forty‐nine of the remaining 60 patients (97%) with incomplete fractures were managed conservatively, while the remaining 11 patients were managed with CRPP. All patients with incomplete fractures showed bone healing and no evidence of lateral condyle displacement on follow‐up radiographs. Conclusions The Song stage 2 or 3 classification is not entirely accurate and is inadequate at guiding treatment outcomes. The cartilage hinge was most likely located posteroinferiorly within the distal humeral epiphysis. According to our findings, conservative treatment with an effective cast or splint may be sufficient for bone healing in case of incomplete cartilage fractures.