Introduction

Radial neck fractures in children are rare, accounting for 1-3% of all childhood trauma and 5-10% of elbow fractures [1]. The reported mechanism of injury is typically a fall onto an outstretched arm and extended elbow [2]. The most vulnerable age group for this type of injury are children aged 9-10 [3].
Several surgical treatment methods are available for children with radial neck fractures including a close reduction and in cast immobilization, a percutaneous pin reduction, elastic-stable intramedullary nailing (ESIN) and an open reduction with or without internal fixation [4]. The choice of treatment approach depends on the angulation of the radial head [5].
A severe displacement of the fracture can lead to a higher incidence of complications, such as a limited range of motion (ROM), pain, instability, neurovascular trauma, a premature physeal closure, cubitus valgus, radial head overgrowth, avascular necrosis and improper ossification [6–9]. Therefore, the treatment outcome depends on the injury type, treatment method and presence of complications.

Aim

The purpose of the study was to evaluate the clinical and radiological outcome of patients treated in our department with ESIN, regarding different radial head angulations and to search for risk factors of a poor outcome.

Materials and methods

A total of 26 consecutive patients treated for a radial neck fracture between October 1, 2020, and March 1, 2022, at a single department were included in the study. The patients’ age ranged from 5 to 16, with a mean age of 9.4 years. There were 18 girls and 8 boys. Twenty-three patients had an injury to the left limb and 3 to the right limb.
A radiological evaluation was performed before surgery, the next day after surgery and at the last follow-up visit. The radiographs were taken in anteroposterior and lateral projections. The angulation measurement was conducted by determining the angle between a line perpendicular to the articular surface of the radial head with a line drawn through the radial shaft axis. The Judet classification was used to classify the severity of the injury: Judet I – an undisplaced fracture, Judet II – angulation <30°, Judet III – angulation ranging 30-60°, Judet IVA – angulation ranging 60-80°, Judet IVB – angulation > 80°. All patients underwent a percutaneous reduction of the radial neck fracture, supervised by fluoroscopy. If the percutaneous method failed, a K-Wire assisted reduction (joystick) was performed. The diameter of ESIN was 60% of the width of the marrow cavity in the anteroposterior projection. If the final angulation of the radial head was >20° or both percutaneous and joystick reduction methods failed, an open reduction with ESIN stabilization was performed. Post surgery, the patients were immobilized in a sling or in a long arm cast for 2-3 weeks, depending on the concomitant injury and surgeons’ opinion about its impact on pain reduction.
Follow-up visits were scheduled at a 6-week interval post surgery. The implant was removed after approximately 6 months after injury based on bone union conformed on X-rays.
The elbow range of motion (ROM) was measured with a goniometer of the affected limb at the last follow-up. Based on ROM, the patients were assigned to three groups: group A (no limitation) – pronation/supination= 80-90°, flexion/extension= 0-150°; group B (mild limitation) – pronation/supination= 60-70°, flexion/extension= 10-130°; group C (severe limitation) – pronation/supination= <60°, flexion/extension= >10⁰/<130°.
The Mayo Elbow Performance Score (MEPS) was used to evaluate patients at the last follow-up, with scores ranging from 0 to 100 points. A score between 90 and 100 points was considered excellent, between 75 and 89 points good, between 60 and 74 points fair and less than 60 points poor.
The follow-up period ranged from 12 to 51 months, with a mean of 25 months. Possible complications, such as avascular necrosis, nonunion, proximal synostosis, heterotopic ossification, infection, and premature physeal closure were documented. The local Research Ethics Committee granted an exemption for this study.
The normal distribution of continuous values was analyzed using the Shapiro-Wilk test. Changes in radius neck angulation were analyzed using the Kurskal-Wallis test. An independent samples t-test was used to determine the two-sided probability of statistical significance. When the distribution was nonparametric, a Mann–Whitney U test was performed. Fisher’s test was used for categorical variables. Correlations were analyzed with Spearman’s rank correlation coefficient. A p-value <0.05 was considered significant. Statistical analyses were performed using MedCalc for Windows, version 15.8 (MedCalc Software, Mariakerke, Belgium).

Results

All patients achieved bone union. The time from injury to treatment was 1.31 days (range 0-18 days). The radial neck fractures were isolated in 16 patients. Ten patients presented concomitant injuries, Table 1. The injury severity according to the Judet classification is presented in Table 2.
Closed repositioning with ESIN was performed in 15 patients. The K-wire assisted method was used in 9 patients and an open reduction was conducted in 2 patients. Immobilization with a cast was used in 10 patients, with a sling in 14 patients and 2 patients had no immobilization post surgery. The implant was removed after 5.7 months (3.2-13.5).
The angulation before surgery was 42.4° (20.1° – 105.6°) and the next day after surgery was 6.9° (1.7°-19.3°), p = 0.0001. In 15 patients reposition was perfect (<5° angulation), in 6 good (5°-10°) and in 5 acceptable (11°-20°). Further correction associated with growth modulation was revealed and at the last follow-up angulation was 2.5° (0°-18.0°). The difference between postoperative measurement and at the last follow-up was statistically significant p = 0.001.
We found no avascular necrosis, proximal synostosis, heterotopic ossification, infection nor premature physeal closure in the evaluated group.
There was no nonunion, but one prolonged healing, due to a secondary injury. Bone union was achieved without additional procedures. The implant was removed after 5,5 months. One patient required early implant removal (3.2 months) due to a conflict of the end with the skin.
Two patients (5.5%) presented a reduced range of motion (more than 20 degrees) of the affected limb at the last follow-up. The patients ROM fulfilled the criteria of ROM groups as follows group A = 21, group B = 3, group C = 2, Table 2.
The average MEPS score was 97.7 points (85-100). There were 22 excellent results and 4 good. The patients with Judet IVB 50% had excellent and 50% good results versus 91% of excellent and 9% good results in other patients, Table 2. The difference in the MEPS score between Judet IVB (92.5 points) versus other patients (98.6 points) was statistically significant, p = 0.04674.
The difference of the MEPS score between Judet II, III and Iva combined with Ivb was not significant, p = 0.1760, however in Judet III 100 had 86.7% and in Judet IV (A and B) 60%, Table 2.
There was a tendency to a weak negative correlation of post-injury angulation and the MEPS score, however it was on the borderline of significance r = -0.37, p = 0.0631
There was no correlation with the MEPS result and the age of the patients; r = -0.23, p = 0.2680, nor with the number of days between injury and surgery; r = 0.1409, p = 0.4925.
There was no statistically significant difference in the MEPS, ROM, cast use and method used to treat between patients isolated versus those with concomitant injuries, Table 3.
However, severe limitation of ROM (group C) was only found in patients with concomitant injuries, Table 3.
There was no statistically significant difference in the MEPS, ROM, and the treatment method between patients immobilized in a plaster cast or in a sling, Table 4.
The reduction method was associated with an initial angulation of the fracture. There was no significant difference in the MEPS, ROM, concomitant injury and immobilization, Table 5.

Discussion

The treatment of a rare type of fractures is often challenging and is associated with controversies. In radial neck fractures most authors agree that a displacement of more than 30° angulations (Judet type III and IV fractures) should be surgically treated [1, 10–12].
However, we agree with a more recent idea that an angulation of more than 30° requires a reduction and surgical treatment for children under the age of 10 and more than 15° for children under the age of 10 [3, 5].
Our research was dominated by the Judet III type fractures and the Judet IV type fractures were much more seldom. However, in our case, we had 7 patients with Judet type II fractures, all of them with an angulation of over 20°, who were treated surgically. Five of them due to their age being over 10 and two who were treated operatively due to concomitant injuries. There are other authors who reported the surgical treatment of patients with an angulation below 30° [3].
The radiological outcome of our study was good and although not all patients had a perfect reposition, further growth modulation occurred. In our study, residual angulation did not exceed 19.3°. According to Métaizeau et al. angulation greater than 10-15° in children aged 12 or 20-30° in younger children will not remodel by growth [13]. According to Koca et al. any residual tilt greater than 20 is related with poor outcomes, which could affect functional results adversely [4].
We chose the MEPS score to evaluate the functional results of treatment as an easy way to evaluate functional factors based on everyday activities, such as combing hair or putting on a T-shirt to evaluate dysfunctions in everyday life [14]. It is a widely used questionnaire in the evaluation of radial neck fractures [4, 5, 10].
There was no MEPS below good. There was a tendency for a correlation of a worse MEPS score with a higher initial angulation and the MEPS score was lower in the Judet IVB group. This is in line with other studies concerning this issue [10, 12].
Complications of proximal radial head fractures include limited ROM, avascular necrosis of the proximal radius, early growth plate closure resulting in radial head deformities or affection of the length growth. The proximal radial epiphysis is mainly supplied by periosteal blood vessels running from distal to proximal; the fracture itself or dissection required for an open reduction may disturb the blood supply and may lead to avascular necrosis of the radial head or physeal closure [5]. It is suggested by Metaizeau that a closed reduction with ESIN stabilization allow to preserve the soft tissues and, therefore, decrease the risk of occurring complications [13]. In our study 2 patients experienced significant limited ROM, even though intensive rehabilitation was conducted. Both patients had concomitant injuries of the elbow.
We found in our study that this type of fracture is more common in girls, 69%. The higher prevalence in girls is in line with other authors. Krupa et al. [3] and Kistcher et al. [10] reported that this type of fracture concerns 57% of girls, and Koca et al reported 63%[4], Prathapkumar 64% [15]. However, reports of equal distribution can also be found [16, 17].
Another interesting finding was that most of our patients injured their left upper limb 88.5%. Such a difference can be found in other studies e.g. Kruppa et al., 68% [3] or Koca et al., 73% [4], however, there are studies reporting more equal distribution between limbs e.g. Klither et al. 57% [10, 17]. We did not find the exact reason for this difference; however, it may be associated with protection against the fall and strength of both arms. Unfortunately, we do not have data concerning which hand was dominant. It could be helpful in explaining this phenomenon.
The application of cast immobilization after ESIN stabilization is still controversial. Most authors apply long-arm cast immobilization for 2-3 weeks post surgery [3, 4, 11, 17, 18]. Klitcher et al. applied a long arm cast in some cases for 1 week to reduce pain. Only patients with associated injuries required longer immobilization in a long-arm cast for 2 to 3 weeks [10]. Although, it is obvious that in the case of an unstable fixation or a concomitant injury immobilization is necessary, in our department there are surgeons who do not find a positive effect of in cast immobilization in other situations. We used this study to evaluate this approach and we did not show positive or negative long-term effects of cast immobilization; however, the short-term results of this issue were not evaluated.
A huge benefit of the study is drawing attention to the issue of immobilization in a cast and an analysis of radial neck fractures in many aspects.
The limitation of this study is a small number of patients, which can be justified by the low prevalence of this injury. What is more, it is comparable or greater than most published studies concerning this issue [3–6, 15, 19]. Another limitation is lack of randomization in in cast immobilization. This issue needs to be evaluated more precisely with an analysis of the time of return to full ROM and pain assessment.

Conclusions

Closed reduction with the use of elastic stable intramedullary nailing can be considered a safe procedure with a low rate of complications. It provides good correction with the possibility of further radius axis remodeling. Patients with an angulation >80⁰ revealed a worse functional effect. In cast immobilization did not reveal a negative or a positive impact on the treatment result.

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