Unpowered scooters are not only a popular form of childhood recreation but also have become one of the main choices for transportation because they are light, portable, and easy to handle. The enormous increase in scooter popularity has led to an increase in the number of reported scooter-related injuries (1–6). In 2001, 16 deaths were reported to the Consumer Product Safety Commission (CPSC)'s National Electronic Injury Surveillance System (NEISS) in the United States, 11 of which were in children (7). The CPSC reviewed the alarming injury data and recommended that children under the age of 8 years should not ride scooters without close adult supervision; children should not ride scooters on streets, near traffic, or in the dark; and children should wear helmets, knee pads, and elbow pads while riding a scooter (7, 8). Several studies have reported that wearing protective gear reduces injuries, and efforts are being made to change the perceptions of riders and parents through research and campaigns (9, 10). Nevertheless, the number of scooter-related injuries remains high (11, 12).

In Korea, unpowered scooters are called “kickboards” or “ssing-ssing car” and are particularly popular among preschool-aged children. Scooters are made of lightweight aluminum, with small low-friction wheels, a front handlebar, and a back-wheel brake. Two-wheeled scooters are most common in other countries and are popular with children of school age or older (1, 8, 13, 14). On the other hand, most of the popular scooters in Korea are equipped with three small wheels (two front wheels and one rear wheel). Scooter-related injuries have dramatically risen over the last few years in Korea, highlighted by the number of cases reported to the Consumer Injury Surveillance System (CISS) of the Korea Consumer Agency (KCA) of 184 in 2015 to 852 in 2019 (15). However, to date, there is no published literature describing scooter-related injuries in Korea.

This study reports the first series of children with unpowered scooter-related injuries in Korea. Our study aimed to describe the injury characteristics of children presenting with scooter injuries in a single institution over 12 years and to highlight the frequency and severity of the injury. We hope that this approach will help propose a prevention strategy and establish a legal basis in Korea.

This is the first study of unpowered scooter-related injuries in children in Korea. We found that the most distinctive feature of scooter injuries in Korea is the young age (mean age: 5.2 years). Many studies report an average age of 9–11 years, and to our knowledge, this study's mean age of 5.2 years is the youngest (9, 10, 17, 18). In 2001 NEISS data in the US showed that 85% of persons treated in the ED for unpowered scooter-related injury were children aged <15 years, and 23% were aged <8 years (7). Younger children have an underdeveloped neuromuscular system and higher center of gravity, which makes balancing more difficult and makes it easy for children to fall off the scooter. Moreover, young children's cognitive immaturity may make them unable to distinguish potential dangers, such as a busy street, downhill, or uneven roads. This led to the CPSC recommendation of an 8-year age minimum for scooter use. The results of this study, which indicated that 88% of children injured on scooters are younger than the CPSC recommended age limit, are very concerning.

In our study, the mechanism and pattern of injury corresponded with findings from other research, but there were more head and face injuries than in other studies (7, 8, 10, 18). Kubiak et al. have reported in their study that a decrease in head injuries was noted with increasing age, while the proportion of extremity injuries increased simultaneously (19). In this study, 65.1% of injuries were to the head and face; this higher percentage is explained by our study containing more young children than other studies. Although the majority of head and face trauma patients sustained superficial injuries (e.g., lacerations, abrasion, bruise), there is a potential for serious injury leading to disability or death (3, 20). In our cases, eight patients had a severe head injury (ICI and skull fracture), and one required a craniotomy. All patients with ICI were <8 years old. This shows that younger children are more vulnerable to head injuries, which is a powerful reason for scooters to have safety regulations for younger children.

In the present study, the most common fracture sites were upper limbs. Several studies report that the commonest fractures also involved the wrist; the mechanism of wrist injury is associated with falling with outstretched arms (21, 22). Elbow fracture was the most common in our study. Elbow fracture patients were all under 8 years old, whereas 4 out of 5 wrist fracture patients were over 8 years old. We think that older children fall with their arms outstretched, leading to wrist injuries, whereas elbow injuries in younger children are caused when they fall over the upper body.

The effectiveness of safety equipment on the head, elbow, and knee injuries in similar recreation activities (e.g., with in-line skates, skateboards, and bicycles) has been proven already (23, 24). Many studies show that wearing protective gear cannot prevent but can at least reduce the severity of injuries sustained (1, 3, 19, 21). Bressan et al. reported that not wearing a helmet resulted in an independent risk factor for intracranial injuries on CT in a study analyzing the head injury of a recreational vehicle (6). Our study showed that all patients with ICI had skull fractures. Skull fracture increases the risk of ICI, and this could be avoided only by wearing a helmet. There are studies that emphasize helmet use on scooters, but the proportion of helmet use on scooters is very low compared with other recreational activities (9, 17, 25). In addition, in Korea, there are no guidelines on safe practice and the role of appropriate safety equipment for unpowered scooters. None of our patients wore any protective gear. Legislation and parental awareness are most important in ensuring the use of protective gear. Parents of young children often have the false belief that, because of their age, they are at low risk of injury, reasoning that they travel at low speeds and are less likely to perform stunts (26). However, most injuries occur at relatively low speeds and even under close adult supervision. Continued parental education regarding the importance of protective gear is required. We further believe that the use of protective equipment, especially helmets, should be legally required for children riding scooters.

The place of injuries was recorded precisely in only 66.1% of the patients. Among those, 58% occurred on the roads and the sidewalks. This shows that although scooters are recreational, they are treated as a means of transportation. Scooter riding in public areas is exposed to sudden stops and unexpected circumstances. The small-wheel scooter design makes it difficult to maintain stability when vibrations caused by uneven ground are transmitted to the handlebar. Uneven ground and obstacles are harder to distinguish in the dark. Among children, scooters should only be used in public recreational areas, and nighttime use should be avoided.

In this study, 78.9% of injuries occurred in the last 3 years, showing a rapid increase in recent years. The cause of the recent rapid increase is unknown; we believe that scooters have become popular due to recreational trends and changing perceptions of scooters. The 2019 Child Safety Accident Trend Analysis of the KCA shows an increasing pattern similar to that of this study (15). According to the report, the scooter-related injuries among children <15 years old were 184 cases in 2015, 600 cases in 2017, and 852 cases in 2019, showing a rapid increase since 2016. Until 2017, bicycles were the most common cause of recreational vehicle-related injuries for children <15 years old; however, after 2018, the scooter injury was reported to be higher than bicycle injuries (48.1 vs. 38.8%, respectively). The incidence based on age was 24.9% in children aged between 1 and 3 years, 49.2% in 4 and 6 years, and 25.9% in 7 and 14 years, showing similar results to those of our study. The rapidly increasing number of injuries recently suggests that more research and safety guidelines for scooter-related injuries are needed.

Our single-center retrospective design has a few limitations, particularly with regard to the accuracy of data reporting and generalizability. First, limited documentation prevented us from identifying more detailed injury mechanisms and place, and factors influencing the occurrence of accidents such as weather, ground state, and slope. Furthermore, we could not identify adult supervision and the length of the scooter experience. Second, the diagnosis was based on discharge code and radiographic results, and the ED discharged patients were not followed-up. In patients who did not undergo CT, a missed injury may be present and delayed symptoms may have been overlooked. Finally, our data may not be generalizable to all children injured with scooters. Our center is an ED of a tertiary care center and the sole state trauma center in Ulsan. Severe injuries such as cerebral hemorrhage will be referred only to our hospital, but patients with mild injuries or fractures may visit other hospitals or outpatient clinics. Despite these limitations, this study demonstrates injury characteristics and trends for unpowered scooters in Korea and highlights an important emerging public health issue in children. We hope that it will help in facilitating the safe use of unpowered scooters and developing safety guidelines in the future.

In conclusion, this study shows that unpowered scooter-related injuries are on the increase and are particularly a serious problem among younger children. The head and face are the most vulnerable; these injuries are sometimes serious and require significant intervention. Children and parents should be aware of the potential dangers of scooter riding, and protective gear should be worn. Unpowered scooters should be restricted to use by children over 8 years and should not be used in hazardous environments such as on uneven grounds, on roads, or at night.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

The studies involving human participants were reviewed and approved by Ulsan University Hospital's Human Research Ethics Committee (IRB number: 2020-01-003). Written informed consent from the participants' legal guardian/next of kin was not required to participate in this study in accordance with the national legislation and the institutional requirements.

MC: conceptualization, formal analysis, validation, writing—original draft, and writing—review and editing. MK: investigation. MK and MC: Data curation, methodology, contributed to the article and approved the submitted version. All authors contributed to the article and approved the submitted version.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.