The Presence of Associated Injuries in Pediatric Radial Neck Fractures: A Systematic Review of the Literature and Meta-Analysis of Pooled Individual Patient Data

Abstract

Background: Pediatric radial neck fractures (pRNFs) can occur in isolation or in association with concomitant injuries. It is unknown whether the presence of associated injuries should influence the choice of treatment. The aim of this study is to assess the incidence of associated injuries in pRNF and their correlation with fracture angulation (Judet grade) or the patient's age (under or over ten years of age). Methods: A systematic literature review was performed following PRISMA-IPD guidelines, including case series on pRNF with a minimum of five cases of children until 16 years of age. The quality assessment included a risk of bias analysis and evaluation using the MINORS criteria. Individual patient data on age, Judet classification and associated injuries were extracted from the included studies and pooled for the meta-analysis. The correlation between the presence of associated injury and the patient's age or Judet classification was depicted in two forest plots. Results: A total of 20 articles published sufficient individual patient data (n = 371) on associated injuries. All but one were retrospective case series. Fifteen articles had MINORS scores of 8 or higher. The incidence of associated injuries was 33% (123 of 371 cases). Almost half of the associated injuries included an olecranon fracture (61/123). There was no correlation between Judet classification (p = 0.243) and incidence nor between patient age and the incidence of associated injuries (p = 0.694). Conclusions: Surgeons should be aware of potential associated injuries in over a third of pRNF cases, regardless of the patient's age or fracture angulation. Deduction of the trauma mechanism may be a more useful tool for assessing the potential presence of associated injuries than the most frequently used fracture classification or the patient's age. More research is needed regarding the requirements for enhanced diagnostic imaging, specific treatment or follow-up adaptations in children with pRNFs and associated injuries.

Keywords: elbow injury; pediatric trauma; radial neck fracture; radial neck trauma.

Figure 1

PRISMA-IPD guided search and specification of the inclusion of individual patient data for the analysis of the incidence of associated injuries (green rectangle). Mixed data: pRNF data published mixed with intraarticular fractures or data from adults (Mason classification was used).

Figure 2

The incidence of associated injuries in pediatric radial neck fractures in a pooled analysis of 371 cases.

Figure 6

The Chambers classification and Jeffery classification. In these classifications, a valgus trauma mechanism is recognized with several associated injuries depending on the trauma mechanism.

Figure 3

Distribution of cases among age categories and Judet grades (J). (A) A total of 67/205 patients under ten years of age had associated injuries, compared to 56/166 in patients over ten years of age (p = 0.694; forest plot is depicted in Figure 4A). (B) There is no significant difference between Judet grades for the incidence of associated injuries; p = 0.243; forest plot: Figure 4B.

Figure 4

(A) Forest plot of meta-analysis of pooled individual patient data for patient age. There is no significant difference in the occurrence of associated injuries in patient age groups of under ten years or over ten years of age (p = 0.694). (B) Forest plot of meta-analysis of pooled individual patient data for fracture angulation. The Judet grade is not a predictor of the occurrence of associated injuries; CHI square p = 0.243 [10,22,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43].

Figure 4

(A) Forest plot of meta-analysis of pooled individual patient data for patient age. There is no significant difference in the occurrence of associated injuries in patient age groups of under ten years or over ten years of age (p = 0.694). (B) Forest plot of meta-analysis of pooled individual patient data for fracture angulation. The Judet grade is not a predictor of the occurrence of associated injuries; CHI square p = 0.243 [10,22,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43].

Figure 5

Overview of the most frequently used fracture classifications for pRNFs. Note that in the Mason classification, there is an overlap with intraarticular fractures of the radial head in the same classification. A Mason grade two fracture may be an intraarticular fracture with a >2 mm displacement or an extraarticular radial neck fracture with angulation. No angulation range for distinction between the three Mason grades has been specified. Following the AO-PCCF, a pRNF is coded as 21r: 2 (forearm), 1 (proximal) or r (Radius) and, depending on its location in the proximal radius, as E (epiphysis), M (metaphysis) or D (diaphysis). A separate code is added to specify the fracture pattern and the severity: I: undisplaced; II: a displacement of less than half the shaft diameter; III: a displacement of more than half the shaft diameter. rs = radial shaft. mm = millimeters.

Figure 7

Most frequently described trauma mechanisms for pediatric radial neck fractures and explanation of potential biomechanic pathways of associated injuries. Note that the intact annular ligament may act as a fulcrum. An olecranon fracture may occur due to valgus compression or impingement on the olecranon fossa or as an avulsion of the triceps. Purple: medial collateral ligament (MCL); overlying orange muscle in valgus supination: pronator teres muscle; green shade overlying radial head: annular ligament.