Temporal variation in pediatric supracondylar humerus fractures requiring surgical intervention

Abstract

Background: Pediatric supracondylar humerus fractures commonly require surgical intervention and hospital admission, which is costly and consumes significant health care resources. There are few data regarding temporal characteristics (month, day and hour of injury) of this particular pediatric fracture. We wished to investigate the month, day of the week, and time of occurrence of these fractures to guide appropriate use of health care resources and prevention strategies.

Methods: This study was a retrospective review of clinical records and radiographs of 353 children with operative supracondylar humerus fractures in a temperate climate region over 6 years. Date and time of injury and demographic data (gender, age, laterality) were extracted. Variation in month, weekday, and time of injury was analyzed using circular analysis, cosinor analysis, probability distributions and topographical distribution.

Results: There was a statistically significant increase in the number of fractures during the summer with a peak in early July. When analyzing by month and day of the week, a peak was seen Thursday-Saturday during May-July and middle of the week September-October. Weekdays demonstrated a higher proportion of fractures occurring in the morning and at school. The injuries occurred in the am in 37 and the pm in 241; detailed data were known in 227 with 37 between 0000 and 1159, 51 between 1200 and 1559, and 139 between 1600 and 2359 h. The peak time of injury was 1800 h.

Conclusions: The increase in supracondylar humerus fractures in the spring through autumn in temperate regions indicates that education campaigns reinforcing fall prevention and landing surfaces should be done in the early spring. The hourly data support the need for dedicated early morning operating rooms to care for these fractures.

Level of evidence: Prevalence study, retrospective cohort, Level II .

Keywords: Month; Supracondylar humerus fracture; Surgery; Time of injury; Weekday.

Fig. 1

Occurrence of pediatric supracondylar humerus fractures by month. This distribution was statistically significant (Rayleigh z = 27.95, p ≪ 0.001), with a peak occurrence on July 10 (arrow). Using cosinor analysis, the data can be fit to a curve represented by the equation: number of fractures = 29.5 + 16.5 cos (30t − 188), where t = the time in months (1 = January, 2 = February, etc.) (r² = 0.76, p = 0.002)

Fig. 2

Topographic contour representations of operative supracondylar humerus fractures in a weekday by month visualization. The month is on the x axis and the weekday on the y axis. The lowest contour (fewest fractures) is black and the highest contour (most fractures) is white. Note the peaks in May–July Thursday–Saturday, and September Tuesday–Thursday

Fig. 3

Time of injury for supracondylar humerus fractures. a Time of occurrence for 181 children with operative supracondylar humerus fractures (black bars). Circular analyses results in an average time of ~1640 h (solid arrow); however it does not account for the asymmetric data. When analyzing the proportion of fractures by probability distributions, a better fit (solid line) was the Johnson S_B distribution [10] with a peak time of injury at 1800 (dashed arrow). This was highly significant with a goodness of fit p = 0.99 (Kolmogorov–Smirnov test). Mathematical details of this fit are shown in “Addendum”. b Similar methods were used to analyze the time of day in two hour increments for the data in the present study (black squares) and that from Kuala Lumpur [2] (gray triangles). An excellent fit distribution was the Johnson S_B for both sets of data (solid black and solid gray lines for the present study and Kuala Lumpur respectively). The peak hours of injury in the present study were 1600–1800, and in Kuala Lumpur 2000–2200. These fits were highly significant with goodness of fits p = 0.94 and 0.95 for the present study and Kuala Lumpur study (Kolmogorov–Smirnov test)

Fig. 4

Peak occurrence of pediatric fractures using cosinor analysis. The data come from the present study of supracondylar humerus fractures (solid squares, solid black line best fit; July 10 peak, solid black arrow) as well as pediatric elbow fractures in Malmö, Sweden [4] (open rhomboids, long hatched black line best fit; July 30 peak, long hatched black arrow), pediatric elbow fractures in Ejsberg, Denmark [6] (gray circles, gray line best fit; July 2 peak, gray arrow) and Hong Kong children age 8–11 years encompassing all fractures (open triangles, short hatched black line best fit; July 2 peak, short hatched arrow). These were all significant (p < 0.002, r² ≥ 0.76). The number for the studies from Hong Kong and Malmö are shown on the lefty axis and for Ejsberg and the present study on the righty axis