Abstract
Purpose
Electric scooters (e-scooters) have become an increasingly popular mode of public transportation in recent years. As the incidence of related injuries rises, it is important to understand specific fracture patterns unique to e-scooters and electric bikes (e-bikes) to help guide management. The purpose of this study was to review the prevalence and describe specific fracture patterns of e-scooter and e-bike related injuries at the busiest level 1 trauma center in the borough of Manhattan.
Methods
Chart review to determine mechanism of injury was performed on all patients for whom an orthopedic consult was requested from 1/1/2021 to 12/31/2021. All patients whose injuries were sustained due to an e-scooter or e-bike were further reviewed for demographics, injury characteristics including fracture pattern, and definitive injury management. Any patients who had an orthopedic consult placed for a reason other than an acute injury were excluded. Descriptive statistics are reported as frequency (percentage) for categorical variables and means for continuous variables.
Results
Of the 1815 orthopedic consults requested, 1357 (74.8%) were for acute injury management. Of those with acute injuries, 119 (8.8%) sustained 136 e-scooter or e-bike related injuries. There were 92 (77.3%) males at an average age of (33.8 ± 15.7) years. Approximately one-fifth of all patients presented in June 2021 (26, 21.8%). There was a 9.2% rate of open fractures. The 136 injuries were evenly split between the upper and lower extremities, with 57 (47.9%) upper extremity, 57 (47.9%) lower extremity injuries, and 5 (4.2%) concomitant upper and lower extremity injuries. The most common fracture patterns were ankle fractures (16, 11.7%), followed by tibial shaft (14, 10.2%), tibial plateau (13, 9.5%), and radial head fractures (11, 8.0%). There was a 33.3% incidence of associated posterior malleolar fractures in the spiral tibial shaft fractures, 31.0% of posterior malleolar involvement and 18.8% of isolated vertical medial malleolar fractures in the ankle fractures, and 61.5% of posterior comminution in the tibial plateau fractures.
Conclusion
E-scooter and e-bike related injuries have a high incidence of tibial shaft fractures, ankle fractures, tibial plateau fractures, and radial head fractures. There should be a high index of suspicion for posterior and medial involvement in lower extremity fractures sustained due to e-scooter or e-bikes. Identifying specific fracture patterns seen in e-scooter and e-bike related mechanisms will help guide management of these injuries.
Keywords: Electric scooter, Electric bike, Tibial shaft, Ankle fractures, Tibial plateau fractures
Introduction
In the past decade, there has been a dramatic expansion in the use of electronic scooters (e-scooters) and electric bikes (e-bikes) as convenient and inexpensive modes of transportation in large urban areas.1, 2, 3, 4 Multiple studies have reported a significant number of e-scooter related injuries shortly after e-scooter introduction to different cities and countries.1, 2, 3,5, 6, 7, 8 However, e-scooters have only just begun to become more prevalent in New York city.9, 10, 11 Ride share e-scooters first appeared within New York city in the spring of 2020, yet were quickly put on pause after several e-scooter related deaths, and then re-introduced with reportedly stricter and safer service.9, 10, 11 However, e-scooter and e-bike injuries have continued to be an issue, especially in many large cities.1,7,8,12 As the incidence of these injuries continues to rise, it is important to understand specific fracture patterns that may be unique to e-scooters and e-bikes, in order to help guide surgical planning and operative fixation. The purpose of this study was to review the epidemiology of e-scooter and e-bike related injuries at the busiest level 1 trauma center in the borough of Manhattan and describe specific fracture patterns seen in e-scooter and e-bike related injuries. We hypothesized that e-bike and e-scooter injuries result in an increased prevalence of isolated medial-sided fractures.
Methods
Institutional review board approval was obtained. The medical records of all patients for whom an orthopedic consult was placed from 1/1/2021 to 12/31/2021 were reviewed for mechanism of injury. Any patients who had an orthopedic consult placed for a reason other than an acute injury were excluded. All patients whose injuries were sustained due to either an e-scooter or e-bike were further reviewed for demographics, including age and gender, mechanism of injury (i.e. fall from e-scooter or e-bike, or struck by vehicle while on e-scooter or e-bike), injury characteristics including site of fracture, fracture pattern, open or closed fracture, disposition after initial presentation (i.e. admitted from emergency department or discharged) and definitive injury management (operative or non-operative). Descriptive statistics were reported as frequency (percentage) for categorical variables and mean for continuous variables.
Results
A total of 1815 orthopedic consults were requested within the study period, with 1357 patients (74.8%) having orthopedic consults requested for acute injury management. Of the patients with acute injuries, 119 (8.8%) sustained a total of 136 e-scooter or e-bike related injuries. Fifteen (12.6%) patients sustained multiple fractures. There were 96 (80.7%) who had e-scooter injuries and 23 (19.3%) who had e-bike related injuries. Of the e-bike and e-scooter cohort, there were 92 (77.3%) males at an average age of (33.8 ± 15.7) years. All injuries occurred while riding either an e-scooter or e-bike, and 70 (58.8%) fell off the e-scooter or e-bike, while 49 (41.2%) were struck by a car while riding either device. Approximately, one-fifth (26, 21.8%) of all patients presented in the summer month of June 2021 (Fig. 1).
Fig. 1.
Incidence of e-scooter/e-bike injuries per month.
There were 50 (42.0%) patients admitted directly from the emergency department (ED) at initial presentation. However, a total of 59 (49.6%) patients underwent operative treatment, as 19 patients were discharged from the ED at time of presentation and returned later for outpatient surgery. Ten of the admitted patients were treated non-operatively for their orthopedic injuries. There was a 9.2% incidence of open fractures. Twenty-seven (22.7%) patients had additional non-orthopedic injuries.
The 136 injuries were evenly split between the upper and lower extremities, with 57 (47.9%) upper extremity injuries, 57 (47.9%) lower extremity injuries, plus 5 (4.2%) concomitant upper and lower extremity injuries (Table 1). The most common fractures were ankle fractures (16, 11.7%), followed by tibial shaft (14, 10.2%), tibial plateau (13, 9.5%), and radial head fractures (11, 8.0%).
Table 1.
Total e-scooter/e-bike injuries by location (n = 136).
| Injuries by location | n (%) |
|---|---|
| Upper extremity | |
| Shoulder | 18 (13.2) |
| Shoulder dislocation | 6 (4.4) |
| Scapula fracture | 4 (2.9) |
| Clavicle fracture | 7 (5.1) |
| Acromioclavicular separation | 1 (0.7) |
| Humerus | 10 (7.4) |
| Proximal humerus fracture | 4 (2.9) |
| Humeral shaft fracture | 1 (0.7) |
| Distal humerus fracture | 2 (1.5) |
| Supracondylar humerus fracture | 2 (1.5) |
| Capitellum fracture | 1 (0.7) |
| Elbow | 22 (16.2) |
| Radial head fracture | 11 (8.1) |
| Radial neck fracture | 3 (2.2) |
| Olecranon fracture | 4 (2.9) |
| Elbow dislocation | 2 (1.5) |
| Monteggia injury | 1 (0.7) |
| Terrible triad injury | 1 (0.7) |
| Forearm | 14 (10.3) |
| Radial shaft fracture | 2 (1.5) |
| Both bone forearm fracture | 6 (4.4) |
| Distal radius fracture | 6 (4.4) |
| Lower extremity | |
| Pelvis | 11 (8.1) |
| Pelvic ring injury | 5 (3.7) |
| Posterior wall fracture (with/without dislocation) | 4 (2.9) |
| Acetabular roof fracture | 2 (1.5) |
| Femur | 7 (5.1) |
| Femoral neck fracture | 2 (1.5) |
| Femoral shaft fracture | 2 (1.5) |
| Distal femur fracture | 3 (2.2) |
| Knee | 4 (2.9) |
| Knee dislocation | 2 (1.5) |
| Knee ligament injury | 1 (0.7) |
| Patella fracture | 1 (0.7) |
| Tibia | 27 (19.9) |
| Tibial plateau fracture | 13 (9.6) |
| Tibial shaft fracture | 14 (10.3) |
| Ankle | 18 (13.2) |
| Pilon fracture | 2 (1.5) |
| Ankle fracture | 16 (11.8) |
| Foot | 5 (3.7) |
| Subtalar dislocation | 2 (1.5) |
| Lisfranc injury | 1 (0.7) |
| Metatarsal fracture | 1 (0.7) |
| Mangled foot | 1 (0.7) |
Of the 16 ankle fractures, there were 4 bimalleolar fractures (2 involving the lateral and posterior malleoli, and 2 involving the medial and lateral malleoli), 2 trimalleolar fractures, 6 isolated lateral malleolar fractures, 1 isolated posterior malleolar fracture, and 3 isolated medial malleolar fractures (Fig. 2). There was posterior malleolar involvement in 5 fractures (31%), and all 3 isolated medial malleolar fractures had a vertical fracture pattern vs. the more common transverse or oblique fracture pattern noted in all medial malleolar fractures occurring in conjunction with a lateral and/or posterior malleolar fracture. With respect to Lange-Hansen classification, the majority (n = 11) were supination-external rotation mechanisms, with 4 supination-adduction mechanisms and 1 pronation-external rotation mechanism.
Fig. 2.
Ankle fracture patterns. (A&B) Radiographs of an isolated vertical medial malleolar fracture and (C–F) radiographs and CT scan of an isolated posterior malleolar fracture sustained due to e-scooter injuries.
Eleven of the tibial shaft fractures (78.5%) were distal one-third fractures, and 12 (85.7%) had a spiral pattern. There was a 33.3% incidence of posterior malleolar fractures in the spiral tibial shaft fractures.
Of the 13 tibial plateau fractures, there were 4 Schatzker II, 4 Schatzker VI, 2 Schatzker IV, and 3 posterior rim avulsion fractures. All tibial plateau fractures had posterior column involvement, and 8 (61.5%) had significant posterior comminution (Fig. 3). Additionally, 38% of the tibial plateau fractures had medial plateau involvement. Tibial plateau fractures were also classified by injury mechanism, as described by Xie et al.13, of which there were 2 varus-extension patterns, 2 valgus-hyperextension patterns, 3 valgus-flexion patterns, and 5 valgus-extension patterns.
Fig. 3.
Tibial plateau fracture pattern. (A–E) Radiographs and CT of a Schatzker VI tibial plateau fracture with significant posterior involvement and (F–J) radiographs and CT of a Schatzker V tibial plateau fracture with significant posterior involvement.
Nine of the 11 (81.8%) radial head fractures were Mason I radial head fractures with 1 Mason II radial head fracture and 1 Mason IV radial head fracture-dislocation.
Discussion
As the popularity of e-bikes and e-scooters continues to rise, the incidence of related orthopaedic injuries will also continue to rise. While there are several studies reporting on the severity of injuries sustained as a result of e-scooters and e-bikes, because these injuries remain a relatively new phenomenon, there is a paucity of orthopedic literature describing the fracture patterns sustained in such injuries and whether they mirror fracture patterns observed in other high-energy injuries. This analysis shows that the overall incidence of e-scooter and e-bike injuries in New York city is comparable to recent literature. Siow et al.8 reported a 44% incidence of e-scooter related orthopedic injuries over a 27-month period at an urban level I trauma center. Similar to our results, 49 patients were treated surgically, with 8 (3.8%) tibial plateau fractures, 6 (2.8%) tibial shaft fractures, and 8 (3.8%) ankle fractures.8 Ishmael et al.1 also reported on 75 operative e-scooter related injuries, with 43.8% upper extremity injuries, 57.5% lower extremity injuries, and a 12.3% rate of open fractures. This series included 9 tibial plateau fractures, 6 tibial shaft fractures, 6 ankle fractures, 1 both bone forearm fracture, and 6 proximal radius and/or ulna fractures.1 The largest study by Shichman et al.14 reviewed 716 fractures in 563 patients, with distal radius fractures the most common upper-extremity injury and proximal tibia fractures the most common lower-extremity injury. However, the same authors also reported separately on 458 upper-extremity injuries and radial head fractures being the most common upper-extremity e-scooter related injury, which is more consistent with our findings.15 Our results show a greater spectrum of fracture patterns in upper extremity versus lower extremity injuries, although unsurprisingly, the lower extremity injuries were generally more severe (Table 1).
Our initial hypothesis was that e-scooter and e-bike related injuries, particularly lower extremity injuries, would have a higher incidence of medial-sided involvement due to the mechanism of many e-scooter injuries, as riders plant their extended leg to stop, causing a rotational moment on the lower extremity combined with the sudden deceleration. Isolated medial-sided fractures of long bones are observed less frequently than their lateral counterparts, and they have historically been associated with high-energy trauma in orthopedic literature.16,17 Not only can this be explained by the fact that traumatic impact most often comes from the lateral side, but also likely related to the biomechanics of medial-sided bones and bony prominences. For example, the medial tibial plateau is larger and more concave than the lateral tibial plateau, and asymmetrical weight-bearing leads to denser, less fracture-prone subchondral bone of the medial tibial plateau.14,18 As a result, medial tibial plateau involvement is only seen in approximately 8% of all tibial plateau fractures.19 A similar explanation may be given for fractures of the ankle, with a 50% incidence of posterior malleolar fractures reported in ankle fractures sustained due to any mechanism.20 Isolated fractures of the medial malleolus occur in approximately 7% of all fractures involving the ankle.21,22 The lower incidence of isolated fractures of the medial malleolus may be attributable to the strength and stability of the deltoid ligament complex.23 In our series, when medial malleolar fractures occurred in isolation, it was with a vertical fracture pattern versus, whereas the medial malleolus had the more common transverse or oblique fracture orientation when it occurred in conjunction with lateral and/or posterior malleolar fractures. However, our results show that, in fact, posterior involvement was more common in the most frequently occurring lower extremity fracture patterns. Specifically, with respect to tibial plateau fractures, while neither the Schatzker classification nor the injury mechanism classification revealed a specific pattern unique to tibial plateau fractures, when the plateau fractures are examined with respect to the three-column theory of tibial plateau fractures, we found that all tibial plateau fractures occurring in the setting of e-scooter injuries had posterior column involvement. All tibial shaft fractures were distal one-third shaft fractures, with a 50% incidence of posterior malleolar fractures. For the tibial plateau fractures, although 38% of the tibial plateau fractures had medial plateau involvement, all had posterior involvement, and within the ankle fractures, 31% had a posterior malleolar fracture. Additionally, using a descriptive fracture classification based on the malleoli involved as opposed to a mechanism-based system (i.e. Lange-Hansen) better characterized the posterior involvement seen in the ankle fractures occurring in the setting of e-scooters. It appears that the force vector of e-scooter injuries leads to more posterior involvement for lower extremity injuries, and orthopedic surgeons should have a high index of suspicion of posterior involvement in e-scooter and e-bike related lower extremity injuries.
There are several limitations to this analysis. First, this study is retrospective, and thus carries the inherent limitations of a retrospective cohort. Second, as Manhattan only introduced e-scooters in 2020, then went through several periods of banning e-scooter use in the city, there is a relatively limited number of injuries compared to other centers. As a result, only 1 year of data could be reported, and ideally several years of data would better characterize the problem. The authors hope to publish on a larger series, ideally across multiple cities, in future work. Third, all data was collected by chart review, and it is possible that the correct mechanism was not recorded by ED or orthopedic physicians, which limits the number of e-scooter and e-bike injuries identified. Furthermore, no control cohort exists for comparison, but would have significantly strengthened the conclusions of this investigation.
As e-scooter and e-bike injuries become more common, it is important to establish a better understanding of the fracture patterns associated with this mechanism of injury in order to direct injury management and treatment options. Our cohort shows an increased incidence of posterior involvement in lower extremity fractures associated with e-scooter and e-bike injuries, which will help guide the orthopedic management of these injuries.
Funding
Nil.
Ethical statement
Institutional review board approval was obtained.
Declaration of competing interest
None of the authors have financial or institutional disclosures to report related to this research.
Author contributions
Nina D. Fisher: data analysis, manuscript writing/editing.
Ekenedilichukwu Nwakoby: data collection, manuscript writing.
Hunter Hernandez: data collection.
Toni M. McLaurin: study conception, manuscript editing.
Footnotes
Peer review under responsibility of Chinese Medical Association.
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