Orthopedic Injuries Related to Personal
Mobility Devices - A Retrospective
Ke Xin Magneline Ang*, SBM Darshana Chandrakumara, Charles Kon Kam King and Sir Young James Loh
Department of Orthopaedic Surgery, Changi General Hospital, Singapore
Submission:August 05, 2020; Published: August 14, 2020
*Corresponding author: Dr Magneline Ang Ke Xin, Department of Orthopaedic Surgery, Changi General Hospital, Simei Street 3, Singapore 529889, Singapore
How to cite this article: Ke Xin Magneline Ang, SBD Darshana Chandrakumara, Charles Kon Kam King, Sir Young James Loh. Orthopedic Injuries
Related to Personal Mobility Devices - A Retrospective Observational Study. Ortho & Rheum Open Access J. 2020; 16(5): 555946. 10.19080/OROAJ.2020.16.555946
Purpose: Personal mobility devices (PMDs) are increasingly common and progressively being adopted as a mainstream mode of transport. The main objective of this study was to evaluate the demographics, injury pattern and use of protective equipment in patients admitted following PMD-related injuries over a 15-month period.
Methods: All patients admitted to the Department of Orthopedic Surgery between December 2016 to February 2018 with injuries due to PMD accidents were recruited. Data collection was performed retrospectively on the injury pattern, use of protective equipment, patient profile, day and time of injury.
Results: 43 patients were included in this study. Incidence of PMD accidents resulting in orthopedic injuries was higher in patients aged 40 or less (n=29 vs n=14). The accidents occurred more commonly at night and around the weekend period. Across both age groups, at least 80% of patients sustained fractures with at least 30% having more than 1 fracture and 77% requiring surgery. There were more upper limb injuries. The use of protective gear was low at 20% or less. The patients aged above 40 were more likely to sustain open fractures as compared to their younger counterparts (p=0.042).
Conclusion: The use of PMD as a mainstream modality of transport can result in significant orthopedic injuries and hospitalization. The legislation on the mandatory use of protective equipment and the regulation of PMD use in public can help mitigate this.
Keywords: Personal mobility devices; e-scooter, e-bikes; Fracture; Accident
Abbreviations:PMDs: Personal Mobility Devices; GCS: Glasgow Coma Scale; ISS: Injury Severity Score; LTA: Land Transport Authority; AMA: Active Mobility Act
The use of personal mobility devices (PMDs) has become increasingly common worldwide. Initially comprising of conventional bicycles and kick-scooters that were used for leisure and recreational purposes, the types of PMDs now available have also increased in variety. The current range of products come in power-assisted or even fully motorized forms, such as electric bicycles (e-bikes), electric scooters (e-scooters), hover boards and mono-wheels, to name a few. In Europe and the United States, these PMDs have experienced rapid growth since the late 1990s as they have been marketed as efficient and cost-friendly modalities of transport. Additionally, they provide a “green” alternative to motorcycles and cars due to their low energy consumption, and overall reduce the number of vehicles on the roads. Progressively, fully powered devices are being preferred over conventional
bicycles and scooters as they enable users to travel longer distances .
Alongside the rise in use and numbers of PMDs came the installation of powerful motors and batteries that aided these devices to reach greater speeds of up to 100km per hour (30 mph) and run for longer durations . However, safety features had not evolved in tandem with this increase in speed of PMDs. There are limited infrastructure modifications to accommodate these devices. As such, the number of traffic accidents has also increased tremendously in countries that have adopted these vehicles [3,4]. PMD riders on the roads are more likely to be injured as compared to car drivers, as they ride in the open rather than inside the steel cage of a car frame. Without the car’s structural protection, the PMD rider involved in a crash is more likely to be thrown off and
sustain serious or fatal injuries. Furthermore, 2-wheel vehicles
are inherently unstable in comparison to 4 wheeled vehicles.
Although they appear similar to other 2 wheeled vehicles such as
motorcycles, they lack features such as side mirrors, headlights
or even air bags as in motorcycles that can help reduce the risk
of a crash or the severity of the injury. PMD riders going on
conventional bicycle lanes puts the slower moving cyclists and
pedestrians at risk of collisions as well .
The main objective of this study was to evaluate the injury
pattern of patients following PMD-related accidents admitted
to the orthopedic department in a tier 2 trauma center. The
secondary objective was to determine the use of safety equipment
and patient profile.
This is a retrospective observational study. The waiver of
informed consent by institutional review board was granted as
only retrospective and de-identified data was used. All patients
admitted to the Department of Orthopedic Surgery with injuries
associated with PMD accidents were entered into a registry over
a 15-month period between December 2016 and February 2018.
This was done by diligently reviewing all daily admissions over
the study period and identifying patients who were hospitalized
following accidents related to all PMDs including e-scooter,
e-bikes, electric hover boards and electric mono-wheels. The
demographic details of the relevant patients were captured in
the registry database. The registry included patients who were
admitted directly from the Emergency Department as well as
patients who were admitted from the orthopedic specialist
outpatient clinic. However, it did not include patients with PMD
injuries who were admitted under other specialties and those who
may have died on scene, on the way to the hospital or discharged
from the Emergency Department. The patients managed solely in
the outpatient clinic were also excluded.
The demographic details of the subjects, type of road
user, circumstances of accident, mechanism of injury, injury
severity, and nature of the injury were traced from the registry
database and collated. The demographic variables considered
were age, sex and race. The type of hospitalized road user was
categorized into riders, pillion riders and pedestrians. The
details on circumstances of accident included the time and day.
The mechanism of injury was divided into direct impact, fall on
outstretched hand and others. The severity of injury was assessed
by Glasgow coma scale (GCS) on admission and injury severity
score (ISS). The details on nature of injury comprised the region of
body affected, number of fractured bones, open or closed nature
of fractures and the Gustilo classification for open fractures (if
any). The region of the body involved was plotted on the Barell
injury diagnosis matrix , which was divided into head and neck,
spine torso, extremities, and system-wide or unspecified. The
extremity injuries were further divided into upper limb and lower
limb. The length of hospital stays, number of hospital admissions,
type of bed occupied (general ward, high dependency or intensive
care unit bed), surgical management and number of surgeries
(if any) as well as discharge destination were collated. After
tabulation of results, data analysis was performed using IBM SPSS
Statistics 20.0 software, using Chi-square test and Fisher’s exact
test as appropriate. A p-value < 0.05 was taken to be statistically
During the study period from 1st December 2016 to 28th
February 2018, 43 patients with PMD-related injuries were
admitted to the Department of Orthopedic Surgery. 38 patients
(88.3%) were involved with accidents related to e-scooters. Of the
remaining 5 patients, 2 patients (4.7%) had accidents involving
e-bikes, 2 patients (4.7%) had accidents involving electric hover
boards and 1 patient (2.3%) had an accident involving the
electric mono-wheel. 40 out of 43 patients (93%) were riders,
2 patients (4.7%) were pillion riders and 1 patient (2.3%) was
a pedestrian. Majority of the accidents (n=25, 58.1%) happened
at night (between 7pm and 6am), as shown in Figure 1. The
hospitalization trend was also analyzed according to days of the
week. More accidents tended to occur on or closer to the weekend,
as shown in Figure 2.
The majority of the patients were male (n = 36, 83.7%) and
of Chinese race (n = 31, 72.1%). Most of the patients were age
40 years or younger (n = 29, 67.3%). For the rest of the analysis,
demographic data, details of accident and injury characteristics
were compared between the age groups of 40 years old or
below and above 40 years old, as shown in Table 1. There were
significant differences between ethnic distribution (p = 0.045) and
day of accident (p = 0.003) amongst patients of the 2 age groups.
Most injuries were sustained from self-skidding and across both
groups; use of protective gear was low at 20% or less. At least 80%
of patients sustained fractures and at least 30% had more than 1
fracture, with 34 patients (77%) requiring surgical intervention.
Patients aged above 40 were more likely to sustain open fractures
as compared to their younger counterparts (p=0.042). Upper
limb injuries were more common in older patients than younger
patients (85.7% vs 56.5%), although this was not statistically
significant. Most patients were managed in the general ward and
more than 90% did not require further institutionalization after
treatment in an acute hospital.
To our knowledge, this is the first study that attempted to
study inpatient orthopedic injuries related to PMDs in Singapore.
PMDs started out as novelty toys and are rapidly rising in
popularity globally. They are gradually being adopted as the
mainstream mode of travel. In the local context, many in the food
delivery service have even become dependent on these devices
for sustenance of their daily livelihood, using PMDs as their main
mode of transport for the job. Unfortunately, there has also been a
worrying upward global trend of accidents [7-9] associated with
PMDs. The current study described 43 patients with orthopedic
injuries that warranted admission. The demographic profiles
of patients were similar to two other relevant local studies
[10,11] performed to evaluate PMD-related injuries, with male
predominance, more young patients and majority of patients
being Chinese in ethnicity.
Cha et al.  reviewed injury patterns sustained by PMD
users presenting to the emergency department in Singapore. The
severity of injuries was similar to that in the current study, with
majority of patients having ISS less than 9. The nature of injuries
was different with majority being external wounds (89.2%) such
as abrasions and lacerations instead of fractures, as their study was
based on patients seen at the emergency department. However,
the anatomic distribution was similar with upper limb injuries
being more common than lower limb injuries. This phenomenon
could be explained by the instinctive human response to use their
upper limbs to break falls or brace themselves for the impact
of a collision. In the current study, more than 30% of patients
sustained more than 1 fracture from their accident.
Tan et al.  evaluated factors associated with injury
severity and hospitalization in PMD riders across a range of PMD
types using information from the Singapore National Trauma
Registry and found that older age was an independent risk factor
for severe injury and hospitalization. We found a significantly
greater proportion of patients in the age group greater than 40
years old sustaining open fractures instead of closed fractures. A
possible contributing factor is slower reaction and less tissue bulk
in the relatively older age group. However, the current study did
not show significant difference in age of patients who sustained
higher ISS or required admission to the high dependency or
intensive care unit. More than 90% of patients in both age groups
were discharged home after approximately a week’s recovery in
In the current study, there was a gross lack of protective gear
being worn by PMD riders - less than 20% of all patients had
protective gear on at time of accident. This was also noted in other
studies performed locally and internationally [10-14]. There
is currently no legislation mandating the use of protective gear
such as helmets or limb-guards when riding PMDs. Authors have
advocated the use of wrist guards to reduce the risk of injuries in
skaters, and this might find similar application in this cohort of
The main mechanism of injury appeared to be skidding of
the PMD. There appears a higher incidence (more than 50%) of
such accidents occurring at night (Figure 1) and over a weekend
(Figure 2). We need to consider performing prospective studies to
evaluate the factors contributing to this trend, such as correlation
to holidays, road or weather conditions, influence of alcohol, the
speed at which the PMD rider was travelling at the time of the
accident, as well as purpose of PMD use during time of accident
(for leisure or occupation related, such as deliveries).
Many countries including Canada, China and the United States
have all passed legislation regarding PMDs. In Singapore, PMDs
are regulated by the Land Transport Authority (LTA) . The
Active Mobility Act (AMA) was enforced in May 2018 after the
study period to regulate the sale of mobility devices and their
use on public paths. However, there were at least 3,700 reported
accidents  within the first year of implementation of the
AMA. The first fatal collision was reported in September 2019
 when a cyclist died after being involved in a collision with a
PMD rider. Currently, all PMDs have been banned from footpaths.
The current study was conducted prior to AMA and it would be
useful to determine the incidence of PMD related injury after the
There were several limitations to the current study. Firstly,
this is a pilot study comprising a small population of only 43
patients over a 15-month period, which may not be representative.
Secondly, as this was a retrospective study, the data collected
relied on the accuracy and completeness of the registry and
electronic medical records.
The use of PMD use as a mainstream modality of transport
can result in significant orthopedic injuries especially in the upper
limbs and requiring admission to hospital. The spectrum of such
injuries ranges from open fracture to multiple fractures in the
upper limb. There exists a need for stricter regulations on its use
in public and the mandatory use of protective gear to mitigate the
risk of such injuries.