Electric scooter-related orthopedic injuries: the experience of an Italian orthopedic center and literature review

Introduction

Standing electric scooters (e-scooters) were first introduced in 2017.1 Nowadays, they have become increasingly popular as a part of urban micromobility. Their popularity increased during the COVID-19 pandemic, partly because people sought alternatives to both cars and overcrowded public transport. Due to their widespread availability and opportunity to end the ride anywhere in the city, e-scooters were a smart alternative to support social distancing. Moreover, these micromobility vehicles are considered a valid, green and cost-effective alternative to carbon fossil-based vehicles.

On the e-scooter, the rider stands with the feet in line, at the two ends of the platform are the two wheels, while the steering bar is attached to a stick reaching approximately the waistline. For rental e-scooters, the speed limit is automatically set to a 25 km/hour, which decreases to 6 km/h in pedestrian areas.2

In 2021, 17.9 million e-scooter rentals were reported, doubling compared with the previous year. Likewise, the number of subscriptions to e-scooter rental services significantly increased (+144% compared with 2020). In 2021, a total of 45.900 e-scooters were available for rent in 39 Italian cities. The mean ride duration reported is about 11 min, while the average traveling distance is 2.3 km.3 Thanks to the increasing popularity of this phenomenon, the Italian government published a decree regarding e-scooter usage in August 2022. The decree outlines the technical features e-scooters must have in order to circulate on Italian territory, including requirements for lights, plates, weight and several technical issues.2 Moreover, an update of the Italian traffic laws was developed in order to include e-scooters: people underage can rent an e-scooter, but if they do, the use of a helmet is mandatory.4 The lack of a requirement for specific training before rental, as well as the absence of a specific license and driving regulations, exposes riders to a high risk of trauma. Hence, this phenomenon is opening the doors to a new field of orthopedic traumatology. In the scientific literature, there is an increasing number of case series regarding e-scooter-related injuries. These studies reported a growing number of e-scooter-related injuries, emergency department (ED) admissions and hospital admissions. One of the first studies on the subject described a high incidence of orthopedic injuries in a hospital in California, with the most common injuries being those affecting soft tissue, craniofacial areas and limbs.5

Although e-scooters may not typically be considered a mode of transportation that may cause high-energy injuries comparable to motorcycle injuries, casualties and healthcare costs for e-scooter-related injuries have been reported, making it crucial to highlight this topic to the general public.6–8

The aim of this study was to analyze the patient flow changes in the ED of an Orthopaedic Trauma Hub in Milan (Italy) from May to November 2021 with a special focus on e-scooter-related injuries and a comparison with the modern literature.

Materials and methods

A case series and systematic review were performed in order to delve deeper into the significant issue of the increasing incidence of scooter-related injuries worldwide.

Results

A total of 28 169 patients presented to the ED from May 1 to October 31, 2021: 1955 (6.9%) were involved in two-wheeled vehicle injuries. Of 280 (14.3%) reported an e-scooter injury, 1105 (56.5%) a bicycle injury and 570 (29.2%) a motorbike injury (table 1).

Out of the 280 individuals involved in e-scooter accidents, 203 were men, with a mean age of 29 years. Seventy-two patients were younger than 18 years. The demographic features of the patients are reported in table 2.

All patients were evaluated with an imaging exam in the ED, with the most common imaging studies being radiographs (290 X-Rays on 280 patients). Among the 290 E-scooter-related traumas reported, 123 (42%) were fractures, and 167 (58%) were contusions (table 3).

In e-scooter accidents, the most common modality of collision was the loss of balance resulting in a fall (82%), rather than collisions with other objects/people/vehicles. The most common fracture locations were the upper extremity with the elbow being the most frequently involved joint. The most common localization for soft tissue contusions in the upper limb was the wrist and hand region (table 3)

All the contusions concerned soft tissues, and there were no major lacerations.

In the lower limb, ankle fracture was the fracture most frequently observed, making it also the most common joint requiring a surgical procedure (7 surgeries out of 31 traumas). Nonetheless, hip traumas were most likely to result in surgery (five surgeries out of seven traumas, 71%). The most common localization of soft tissue contusion in the lower limb was the knee (table 3).

Traumas related to an exclusively orthopedic ED, in facilities that do not have other surgical and intensive therapies, were taken into consideration. For this reason, the patients who access it are exclusively orthopedic in nature, with at most occasional soft tissue contusions, superficial abrasions and sometimes minor head injuries without cranial fractures or intracranial bleeding. All the patients were hemodynamically stable with a normal GCS. Twenty-eight patients had a documented Injury Severity Score (ISS) with a median ISS of 5 (range: 4–6). An ISS was not calculated or documented for patients who did not undergo surgery. No patient who underwent surgery experienced complications or required intensive care unit access; the average length of hospital stay was 7 days (range: 2–13). The majority of scooter-related injuries occurred before 18:00.

Literature review

The systematic literature review was performed in PubMed/Medline and Embase in July 2022. The literature search flowchart according to PRISMA Guidelines is illustrated in figure 1, summarizing the current data from the paper included in the literature review.

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Figure 1

Flowchart according to PRISMA guidelines. PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

A total of nine studies related to electric scooter orthopedic injuries were included in the literature review (table 4).

Table 4

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Studies analyzed

Electric scooter injuries were analyzed to evaluate injury patterns specifically regarding type, incidence and treatment. The majority of studies were retrospective analysis of ED or trauma service databases. Not all the analyzed studies have reported all types of injuries, and similarly, sometimes patients have reported more than one injury. For these reasons, the sum of injuries does not always reach the 100% of the ‘number of injuries’ column.

English et al and Uluk et al were the studies reporting the highest number of e-scooter traumas11 12 both with 41 traumas/month, while the lowest rate was found by Bascones et al13 with five traumas/month. In all studies, outcome was reported for both the riders and the non-riders injured in the accident.

Most of the studies also analyzed the use of a helmet, reporting an overall low rate of helmet use. At the time of the study, there were no helmet requirement laws in the European countries analyzed. In contrast, in the USA, helmet and ‘rules of the road’ regulations (eg, riding on sidewalks vs streets) vary by locality.

Overall, the population in the studies considered was young: median age was under 40 for all studies. Siow et al and Genc et al observed a low rate of causalities.14 15 Siow reported a statistical positive correlation between age and ISS, with older patients experiencing more severe traumatic injuries.15

Bodansky and English also evaluated the site where the accident had occurred (sidewalks, street, pedestrian area).12 16 In the study by Bodansky et al, patients on e-scooter rentals were most commonly injured on roads, while those on private scooters were mainly injured on pavements. All injuries occurring in pedestrian zones were on rental e-scooters.16

Most of the studies reported alcohol usage: nearly half of the patients had been drinking alcohol in the study by Rizzo et al.17 The highest rate of hospitalization was found by Bascones et al, with more than half of patients needing hospitalization.13

Nine studies localized all injuries into similar body regions (shoulder/humeral fracture, clavicle fracture, elbow fracture, wrist/hand fracture, acetabular/femoral fracture, knee fracture, lower leg fracture, ankle/foot fracture, head fracture and spinal/ribs fracture)

Discussion

In our study, we found that e-scooter-related traumas are very common events, representing a burden for the orthopedic ED; we found a rate of almost 50 injuries per month of patients involved in e-scooter trauma. The upper extremities were the most common fracture location. These findings are in line with those found in literature.

The emerging general population awareness of climate change, together with the need for solo traveling because of COVID-19 pandemic, led to a widespread expansion of e-scooter rental worldwide.19 20 The evolving spread of e-scooters calls for an understanding of their potential consequences, as injuries are common with this type of or mode of transportation. Being a novel technology, the literature on the topic is still limited.

The analyzed studies are heterogeneous in terms of sample size, the number of patients included and the number of e-scooter-related traumas per month. However, the number of injuries observed is often significantly higher than the former. Nonetheless, the different studies took place in different parts of the world and for different periods of time, so the results might not be fully comparable.

As they tend to have a speed comparable to bicycles, most of the traumas tend to be of relatively low severity, even if the study from Bascones13 showed a high rate of hospitalization. Most of the e-scooter-related injuries observed in our study were minor, while 10% of the injuries required surgery.

From our data, the most frequent injury mechanism appears to be the loss of balance, resulting in a fall (82%), followed by collisions with objects, people or other vehicles (18%). This finding aligns with data in the literature, where the data of loss of balance are the most frequent cause ranging from 84.7% in English et al to 94.2% in Yavuz and colleagues.12 14 The only exception is the study by Uluk et al,11 which finds a falling rate of 57%, though it includes other causes of injury like ‘hurt themselves at E-scooter’ or ‘tandem driving’.

In their study, Suominen et al found a head fracture in 15.8% of their patients and intracranial imaging lesion in 19.5% of the time.21 This analysis could be important for cities that are trying to have a helmet law for electric scooter users. Toofany et al found that the most common e-scooter injuries were the combination of head trauma with injuries to the upper and lower extremities.22

The use of knee and elbows pads should be promoted to prevent injuries to the limbs. The most common localization of injury is the extremities, in particular, upper limb: young age could play a role in this localization because reflexes are ready to make the patient assume a defense position while falling. The radius is the most frequently fractured bone: it was seen by Ishmael and colleagues that radial head fracture was the most common elbow lesion, and similarly, distal radius was the most common lesion in the wrist and hand region. Cases of terrible triad injury of the elbow (combination of elbow dislocation, radial head/neck fracture and a coronoid fracture) were also described.5 Similarly, in our study, we found that radius was the most fractured bone following electric scooter accidents. According to the literature, distal radius fractures represent the most common fractures in adults with high-energy trauma, being the documented typical mechanism in younger patients.23

Siow et al described that although the most common orthopedic injuries involved the upper extremity, several patients sustained high-energy lower extremity injuries, including open fractures, pelvic ring injuries, fractures of the acetabulum, hip, femur, tibial plateau and pilon.15 Regarding the site of injuries, our observations are in line with the available literature: the knee was the joint most commonly affected by trauma. Lower limb injuries, which usually involved the knee, ankle and foot, were probably due to the attempt of the rider to break a fall by placing a foot on the road surface to regain balance.24 Coelho and colleagues found that lower limb fractures were more commonly treated with surgery than upper limb; this may be causally related to the speed at the time of the accident.18 This is in line with what was found in our study. Rizzo et al described a significant association between upper versus lower extremity trauma and the presence of open versus closed fractures, indeed, five lower extremity fractures were open compared with one upper extremity fracture.17

Moreover, several studies stressed the low rate of helmet use and the significant rate of alcohol intoxication among electric scooter users. The studies we analyzed show very different data across the world in terms of casualties, hospitalization rate and the role of alcohol consumption. The latter could be due to different reasons, such as the sole declaration by the patient of having been drinking versus blood examination of alcoholemia. Moreover, there is no information about whether alcoholaemia test was mandatory or was only requested at clinicians’ discretion. In our study, there was no information regarding drug and/or alcohol abuse. The high rate of alcohol intoxication, coupled with the higher rate of injuries occurring during nighttime, could be linked to the lack of a requirement for a driving license to rent an e-scooter. Störmann and Coelho have indeed observed a higher rate of e-scooter-related injuries during the evening hours and during the summertime.18 25 This data are in contrast with what we found in our cohort, where most of the electric scooter-related injuries occurred before 18:00.

English et al described the high number of imaging exams requested for e-scooter traumas, reporting that 91% of the patients required some type of imaging, including plain films (71% of all patients) and CT (40% of all patients).12 Therefore, as the number of e-scooter traumas rise, so do the costs related to ED admissions. In a 2-month study, Mayhew and colleagues noticed that 221 plain films and 47 CT scans were performed on 63 patients referred to radiology, which ran into e-scooter-related injuries.6 In a 7-month study from Auckland (New Zealand), 246 medical-ward admissions were registered, with 49 patients undergoing surgery, with an average cost of 1693$ (Australian Dollar) per injury. Twenty-seven per cent of injuries were considered to be related to alcohol abuse.8

Literature on the topic is relatively limited because of the recent implementation of the vehicles, but few studies have extensively investigated the literature on the use of e-scooter like ours. Our study revealed that e-scooter accidents constituted a significant proportion of two-wheeled vehicle accidents presenting at the orthopedic ED of a tertiary center. Future studies are necessary to fully understand the impact of this type of vehicle on orthopedic surgery, considering the growing market for e-scooters, as new companies keep emerging, but with regulatory policies lagging. The lack of updated policies could play a significant role in the spread of e-scooter-related accidents. Therefore, future studies are required to assess if the development of adequate policies could prevent at least some of the injuries currently occurring.

Conclusion

E-scooters are a new, cheap, green and easily accessible means of transport which are understandably increasing in popularity. Although this mode of transportation has many positive attributes, the most significant flaw that needs to be promptly addressed is the risk of injuries. Injuries could be prevented with adequate policies, resulting in a decrease in public cost. It is, therefore, necessary to establish safety policies in line with those for motorcycles, such as the requirement for a driver’s license, the mandatory use of safety devices like helmets and the prohibition of driving after consuming alcohol and drugs. Simultaneously, it is fundamentally important to educate the orthopedic community about the increasing incidence of this relatively new mechanism of trauma.