The ossification center of the medial epicondyle of the humerus appears at the age of 5 to 7. The time when the epiphyses close varies by gender, approximately 15 years for females and 18 years for males. Medial epicondylar fractures of the humerus are common elbow fractures in children, accounting for approximately 12% of all elbow fractures in children. Their incidence rate is second only to supracondylar fractures and lateral epicondylar fractures of the humerus. This type of fracture is prone to occur in children and adolescents with unclosed epiphyses, with a high incidence at an age of 8 to 12 years old. The incidence rate in boys is three times that in girls, and about half of children with elbow dislocation are boys. In terms of diagnosis, since the epiphysis is not visible on X-rays before ossification, it is easy to miss a diagnosis based solely on plain X-ray films. In addition, anterior-lateral X-ray films often underestimate the actual displacement of the fracture fragment, whereas axial films or CT and MRI examinations can more accurately assess the displacement. Therefore, for children who are clinically suspected of having medial epicondylar fractures of the humerus or whose X-ray plain films show unclear displacement, it is recommended to perform axial X-ray, CT, or MRI examinations to confirm the diagnosis. At present, there is still controversy over the treatment plan for this injury, but the consensus is that conservative treatment can be adopted for fractures without apparent displacement. For those with significant displacement or accompanied by elbow dislocation, surgical treatment is required. At present, open reduction is mainly used in surgical treatment. For older children with nearly closed epiphyses, screw fixation can be chosen, whereas for younger children with unclosed epiphyses, Christie's needle fixation is more commonly selected. In recent years, ultrasound-guided reduction has been a research hotspot in the minimally invasive treatment of fractures. Due to its advantages, such as minimal trauma, dynamic monitoring, and reduced radiation exposure, it has been used to treat elbow fractures in some children. However, its application value in the treatment of medial epicondylar fractures of the humerus in children remains to be explored. Medial epicondyle fractures are common elbow injuries in children, ranking as the third most frequent among pediatric elbow fractures. For fractures with significant displacement, surgery is the preferred treatment to restore joint stability. Among surgical options, open reduction and internal fixation with Kirschner wires is a widely used technique that enables anatomical reduction and reliable fixation. In recent years, ultrasound-guided techniques have gained attention as a focus of minimally invasive fracture management in children, owing to their advantages, including the absence of ionizing radiation and dynamic monitoring. However, the application value of ultrasound in the treatment of medial epicondyle fractures remains to be validated.

To explore the differences in clinical efficacy between ultrasound-guided closed reduction (UGCR) Kirschner wire fixation and open reduction Kirschner wirefixation in the treatment of medial epicondyle fractures of the humerus in children.

A retrospective cohort study design was adopted to analyze the clinical data of 45 children with medial epicondylar fractures of the humerus admitted to Anhui Children's Hospital from August 2022 to August 2024, including 26 boys and 19 girls. The age ranged from 3 to 14 years old, with an average age of (9.07±2.93) years old. There were 17 cases on the left and 28 cases on the right. According to the surgical methods, they were divided into the open reduction Kirschner wirefixation group (24 cases) and the closed reduction Kirschner wirefixation group under ultrasound guidance (21 cases). The operation time, fluoroscopy frequency, elbow joint range of motion, and recovery speed were compared between the two groups. The last follow-up time was 6 months after the operation. The Mayo elbow score and the incidence of complications were recorded and compared.

There was no statistically significant difference in baseline data, such as age, gender, and fracture side, between the two groups of patients (P > 0.05). The operation time of the closed reduction Kirschner wirefixation group under ultrasound guidance (47.29±11.02) min was shorter than that of the open reduction Kirschner wirefixation group (63.46±20.10) min (P < 0.05). The number of fluoroscopy (2.86±0.74) times was less than that of the open reduction Kirschner needle fixation group (5.87±2.03) times (P < 0.05). The elbow joint motion angles of the ultrasound-guided closed reduction Kirschner wirefixation group and the open reduction Kirschner wirefixation group at 1.5 months, 3 months, 4.5 months, and 6 months after surgery were recorded, respectively. Repeated measurement data analysis showed that the recovery speed of the ultrasound-guided closed reduction Kirschner wirefixation group was better than that of the open reduction Kirschner wirefixation group (P < 0.05). At the 6-month follow-up after the operation, the flexion Angle (139.57±3.17) ° and the extension Angle (1.20±9.58) ° of the elbow joint in the closed reduction Kirschmann needle fixation group under ultrasound guidance were both better than those in the open reduction Kirschmann needle fixation group (136.00±4.22) ° and the extension Angle (9.26±15.02) ° (P < 0.05). At the 6-month follow-up after the operation, there was no statistically significant difference in the Mayo elbow score between the two groups (P > 0.05). During follow-up, no complications, such as loosening, withdrawal, neurotendon injury, or nonunion, occurred in either group of children. However, two cases in the open reduction group developed incisional infections, which resolved with dressing changes in the outpatient department and oral antibiotics. No infection occurred in the closed reduction Kirschner wire fixation group under ultrasound guidance.

This retrospective study preliminarily indicates that ultrasound-guided closed reduction with Kirschner wirefixation may have potential advantages, such as shorter operation time, less radiation exposure, faster recovery of elbow joint function, and fewer complications in the treatment of medial epicondyle fractures of the humerus in children. This treatment method has promising clinical application prospects and warrants further research and verification.