In a randomized trial of elementary schools in Toronto, Andrew Howard and colleagues show that granitic sand playground surfaces reduce the risk of arm fractures from playground falls when compared with wood fiber surfaces.
The risk of playground injuries, especially fractures, is prevalent in children, and can result in emergency room treatment and hospital admissions. Fall height and surface area are major determinants of playground fall injury risk. The primary objective was to determine if there was a difference in playground upper extremity fracture rates in school playgrounds with wood fibre surfacing versus granite sand surfacing. Secondary objectives were to determine if there were differences in overall playground injury rates or in head injury rates in school playgrounds with wood fibre surfacing compared to school playgrounds with granite sand surfacing.
Methods and Findings
The cluster randomized trial comprised 37 elementary schools in the Toronto District School Board in Toronto, Canada with a total of 15,074 students. Each school received qualified funding for installation of new playground equipment and surfacing. The risk of arm fracture from playground falls onto granitic sand versus onto engineered wood fibre surfaces was compared, with an outcome measure of estimated arm fracture rate per 100,000 student-months. Schools were randomly assigned by computer generated list to receive either a granitic sand or an engineered wood fibre playground surface (Fibar), and were not blinded. Schools were visited to ascertain details of the playground and surface actually installed and to observe the exposure to play and to periodically monitor the depth of the surfacing material. Injury data, including details of circumstance and diagnosis, were collected at each school by a prospective surveillance system with confirmation of injury details through a validated telephone interview with parents and also through collection (with consent) of medical reports regarding treated injuries. All schools were recruited together at the beginning of the trial, which is now closed after 2.5 years of injury data collection. Compliant schools included 12 schools randomized to Fibar that installed Fibar and seven schools randomized to sand that installed sand. Noncompliant schools were added to the analysis to complete a cohort type analysis by treatment received (two schools that were randomized to Fibar but installed sand and seven schools that were randomized to sand but installed Fibar). Among compliant schools, an arm fracture rate of 1.9 (95% confidence interval [CI] 0.04–6.9) per 100,000 student-months was observed for falls into sand, compared with an arm fracture rate of 9.4 (95% CI 3.7–21.4) for falls onto Fibar surfaces (p≤0.04905). Among all schools, the arm fracture rate was 4.5 (95% CI 0.26–15.9) per 100,000 student-months for falls into sand compared with 12.9 (95% CI 5.1–30.1) for falls onto Fibar surfaces. No serious head injuries and no fatalities were observed in either group.
Granitic sand playground surfaces reduce the risk of arm fractures from playground falls when compared with engineered wood fibre surfaces. Upgrading playground surfacing standards to reflect this information will prevent arm fractures.
Current Controlled Trials ISRCTN02647424
Please see later in the article for the Editors' Summary
Playgrounds and outdoor play equipment provide children with a place to let steam off, play creatively, socialize, and learn new skills. And, in a world where childhood obesity is a burgeoning problem, playgrounds provide a place where children can be encouraged to exercise. But playgrounds are not without hazards. Even in well-maintained and well-run facilities, children can hurt themselves by falling off climbing frames, monkey bars, and other equipment or by falling from standing height during playground games such as tag. In the US alone, more than 200,000 children are treated in emergency departments for injuries sustained in playgrounds every year and about 6,400 children are admitted to hospitals because of playground injuries, most of which are bone fractures (broken bones). In fact, playground injuries in the US are more severe and have a higher hospital admission rate than any other sort of child injury except those involving vehicles.
Why Was This Study Done?
Children who fall off playground equipment are nearly four times as likely to break a bone (often in an arm) as children who fall from standing height. To reduce the number of fractures that occur in playgrounds, some governments have limited the height of playground equipment. Some have also set standards for the type of surfaces installed in playgrounds and for the depth of sand or engineered wood fiber in loose fill surfaces. These standards are based on laboratory tests in which headforms (artificial heads) are dropped onto surfaces. However, these tests provide no information about the ability of different surfaces to prevent broken arms and other specific injuries in the real world. In this cluster randomized trial (a study in which groups of people are randomly assigned to receive different interventions), the researchers compare the rates of arm fractures in elementary (primary) school playgrounds in Toronto (Canada) that have wood fiber surfacing with the rates in playgrounds that have granite sand surfacing.
What Did the Researchers Do and Find?
The researchers randomly assigned 37 elementary schools that had qualified for school board funding for replacement playground equipment to receive either wood fiber (19 schools) or granite sand surfacing (18 schools) in their playgrounds. 19 of the schools complied with their randomization (12 installed fiber and seven installed sand); two schools installed sand although they were randomized to install fiber and seven schools installed fiber instead of sand. The researchers evaluated the playgrounds and their surfaces several times during the 2.5-year study and collected data on how playground injuries happened and types of injuries from the schools, parents, and medical reports. Among the schools that complied with randomization, falls from height into sand resulted in 1.9 arm fractures per 100,000 student-months whereas falls into fiber resulted in 9.4 arm fractures per 100,000 student-months. Arm fracture rates and other injury rates were also higher for falls from height into fiber than into sand when all the schools that had installed new surfaces were considered. However, the rates of arm fracture and other injuries that did not involve a fall from height did not vary between surfaces.
What Do These Findings Mean?
The accuracy of these findings is limited by the small number of arm fractures that occurred during the trial—only 20 children who fell into fiber and two who fell into sand broke an arm. The accuracy of the findings may also be limited by the failure of many schools to comply with randomization although the researchers found no obvious differences between the schools that did and did not comply with randomization that might have affected the trial's outcome. However, even with these limitations, the findings of this real-world study indicate that granitic sand surfaces substantially reduce the risk of arm fractures and other injuries caused by falls from playground equipment when compared with wood fiber surfaces. Thus, because falls from playground equipment are more likely to cause a fracture than falls from standing height, if playground surfacing standards are adjusted to reflect the findings of this study (that is, if sand surfaces are recommended in preference to wood fiber surfaces), many arm fractures in children should be prevented.
Please access these Web sites via the online version of this summary at ttp://dx.doi.org/10.1371/journal.pmed.1000195.
Safe Kids Canada provides information about playground safety and other aspects of childhood safety (in English and French)
Safe Kids Worldwide is a global network of organizations whose mission is to prevent accidental childhood injury (in English and Spanish)
The Nemours Foundation, a nonprofit organization for child health, provides information for parents on playground safety
The Royal Society for the Prevention of Accidents provides information on the safety of indoor and outdoor play areas
The US Centers for Disease Control and Prevention provides fact sheets on playground injuries
The US Consumer Product Safety Commission also has information on playground safety, including resources designed for children such as The Further Adventures of Kidd Safety and Little Big Kids, a booklet on play safety written by children for children