Existed classifications of congenital proximal radioulnar synostosis (PRUS) mainly focus on osseous changes and do not cover all types of congenital PRUS, ignoring the role and developing status of the supinator. This study aims to explore the correlation between supinator development and radiographic deformity of congenital PRUS. Pediatric patients diagnosed with congenital PRUS in two pediatric Orthopedic centers were evaluated retrospectively. MRI and radiographic images of their bilateral forearms (including normal ones) were collected. The area of supinator, extensor carpi radialis longus (ECRL), extensor carpi radialis brevis (ECRB), brachioradialis (BRAR) muscle and extensor indicis (EI) muscle were measured on each forearm. The ratios of these muscles were calculated and regarded as an indicator of the developing status of supinator muscle. Twenty-seven congenital PRUS forearms of 16 patients (average 3.45 years) were included. A new MRI & X-ray classification system was proposed to cover all types of radiographic deformity and provide a comprehensive description of supinator development. This study revealed the relation between MRI measured supinator volume and radiographic deformity of congenital PRUS. Supinator muscles were observed in all congenital PRUS cases. A novel classification was proposed, providing a more comprehensive understanding of congenital PRUS.

Background: Displaced supracondylar femoral fractures (SFF) are difficult injuries to treat in children. Several techniques have been widely used but few studies have compared the merits and drawbacks of each surgical intervention in order to analyze clinical values. The aim of this study was to (1) evaluate postoperative and functional conditions after treatments with locking plate (LP) or external fixation (EF), (2) observe adverse events associated with these two techniques, and (3) evaluate the clinical value of these two techniques. Methods: Twenty-eight patients less than 14 years of age were included in this study with supracondylar femoral fractures. They underwent locking plate or external fixation in authors' hospital. The postoperative healing and functional outcome were elevated according to radiographic and clinical measures, including American Knee Society Score (KSS). Fisher's exact test and independent samples t test were used for statistical analysis. Results: All fractures healed without delayed union. The KSS scoring results of locking plate and external fixation groups were both excellent. The alignment of lower limbs was acceptable with knee valgus less than 2°for all involved patients. In addition, leg length discrepancy was less than 1 cm. No acute or severe complications were noted. There was significant difference in union time (p = 0.03), operating time (p< 0.001), intraoperative blood loss (p< 0.001), and limb length discrepancy (p = 0.04) between LP group and EF group. Conclusions: External fixation is superior than locking plate in terms of union, operation time phrases, and intraoperative blood loss. EF techniques are better options for treating displaced supracondylar femoral fracture in children. Level of evidence: Retrospective comparative study; level III.

Purpose Kirschner-wire fixation (KF) and external fixation (EF) for the treatment of displaced supracondylar femur fractures (SFFs) were demonstrated respectively in previous reports. However, there is no paucity of convincing information on better treatment options for children. The aim of this study was to show results of KF and EF in the treatment of paediatric SFFs according to clinical and radiological outcome. Methods A retrospective analysis including 22 displaced closed SFFs was performed. A total of 12 patients were treated with KF, other ten patients were treated with EF. All patients were followed up for at least 24 months. Demographic data, surgical outcomes and postoperative knee function using the Knee Society Score (KSS) scale were evaluated in this research. Results The patients in the KF group were significantly younger than in the EF group (p < 0.001). The KF group had superiority in operative time (p = 0.001), blood loss (p = 0.027) and length of hospital stay (p = 0.001). Clinical healing outcome did not differ between the two groups. The KF group achieved radiological union in a shorter period (p < 0.001), with a better range of movement (ROM) and KSS postoperative score. Conclusion Both KF and EF can achieve excellent outcomes for paediatric SFFs. KF has many advantages in younger children. Level of Evidence IV