Prevalence and pattern of lower extremity injuries due to road traffic crashes in Fako Division, Cameroon

Introduction Low and middle income countries are disproportionately affected with road traffic injuries and the lower extremity is one of the most affected anatomical body parts. There exist very limited data on the pattern of lower extremity injuries in the Cameroon especially in the South West Region. We therefore, hypothesized that lower limb injuries are common in road traffic crashes and motorized two wheelers are the commonest cause. Methods This was a hospital based prospective, cross sectional study. It involved four hospitals (Limbe and Buea Regional Hospitals, Baptist hospital Mutengene and Tiko District Hospital) in the Fako Division. It was carried out for three months. Victims of road traffic crashes received at emergency department of these hospitals during this period were assessed. Crash characteristics and injury characteristics were assessed and recorded. Results We analyzed 411 crash victims, 197(47.93%) had lower extremity injuries. The male to female ratio was 1.4:1. Majority of crash victims were in their 3rd and 4th decades of life. The mean age of patients who had lower limb injuries was 33.30(±16.04). The most vulnerable road users were pedestrians (26.52%) and passengers on motor bikes (38.44%) and the commonest mechanism by which crash victims sustained injuries were: bike-car collisions (22.84%), and bike-pedestrian collisions (19.29%). Commercial motor bikes (62.77%) and taxis (22.38%) were the road users most involved in road traffic collisions. The leg 98(49.75%), thigh 23(11.68%), and knee 20(10.15%) were the most injured anatomical parts of the lower extremity. Fractures 68 (34.52%), lacerations 53(26.90%), and bruises 49(24.87%) were the most recurrent pattern of lower extremity injuries. Conclusion In view of our findings we conclude therefore as follows: The prevalence of lower extremity injuries from Road Traffic Crashes in our study area was 47.93%. Associated risk factors to the road traffic crashes as identified by the victims were bad roads (10.15%) and bad weather (5.05%). The safety gargets were not adequately utilized by our victims, with 87.72% confirming that they did not wear the helmet and 87.50% affirming that they did not wear the seat belt at the time of the crash. The occupations mostly affected in our series were pupils and students (20.3%) and business people (19.2%), then the bike riders (15.23%). We thus recommend that the laws on the use of road safety gargets, especially helmets and seatbelts, be enforced, with riding and driving speeds reduced to below 60km/hour. Road usage should be avoided in bad weather and pedestrians lanes and zebra crossings be provided to minimize pedestrian-car or -bike collision.


Introduction
The global burden of injury is on the rise [1][2][3] and Low and middle income countries have been revealed to be disproportionately affected. They account for about 90% of the overall injury related mortality [3]. Injuries would likely be the 4th leading cause of death by 2030 [4]. The Global Burden for Disease (GBD) predicts that road traffic accidents would rise to 6th place as a major cause of death by 2020, and would continue to rise if no additional road safety majors are put in place. A review study in low and middle income countries revealed that road traffic related injuries accounted for 30-86% of trauma related admissions [5]. In developing countries, motorbikes have emerged as a popular commercial mode of transportation without any corresponding improvement and adaptation of road infrastructures [6][7][8]. This is particularly true for Cameroon where road infrastructures are generally considered very poor. It has been estimated that the number of people who die as a result of traffic injuries in Cameroon is 35 times higher than what has been reported on similar road infrastructures in the United States of America. Vulnerable road users are most affected [9]. One third of traffic injury victims in large cities of Cameroon are motorcyclists [10]. Current data on injuries suggest that vulnerable road users, pedestrians, cyclist and motorized 2 and 3 wheelers constitute more than half (52%) of road users killed on the roads, with pedestrians alone constituting 37% [11]. The majority of persons killed on the roads are young adults, with 62% of all deaths aged between 15 and 44 years [11]. While in developed countries, effective intervention plans are implemented with measurable results [12][13][14], low and middle income countries still lack the most basic epidemiologic data. In Cameroon studies have been carried out generally on the effects of road traffic crashes in various regions and hospitals in Cameroon, but there exist very limited data on the pattern of lower extremity injuries in the country, especially in the South West Region of the country.

Study objectives:
The objectives of this study were: to determine the prevalence of lower extremity injuries; To describe the demographic variables associated with lower extremity injuries; to identify types of lower extremity injuries (fractures, lacerations, contusions, bruises); to identify associated risk factors to Road Traffic Crashes and the use of safety measures by the victims; to identify the occupations most prone to get involved in Road Traffic Crashes.

Study design, study area and setting
It was a hospital based prospective cross-sectional study carried out

Study population and sampling
The study involved every patient that was involved in a road traffic crash and presented with lower extremity injuries plus any associated injuries to the emergency department of the chosen hospitals (the Buea Regional Hospital, the Limbe Regional Hospital, Baptist Hospital Mutengene and the Tiko District Hospital) within the period of the study.

Selection criteria
Inclusion criteria: Patients with injuries sustained from road traffic accidents during the period of the study. Patients with lower extremity injuries admitted in the hospital at start of the study that consented to participate in the study.
Exclusion criteria: Patients from whom relevant data could not be obtained. Victims of injuries secondary to other causes than road traffic crash, and patients who refused to consent to the study.

Sample size
It was estimated using the Lorenz formula as seen below: Where, n = minimum sample size required for this study; p = 53.6%; prevalence of lower extremity injuries following bike accidents in hospital based prospective cohort study in Laquintini hospital Douala.

Study procedure
Patients who presented to the hospital with road traffic injuries were approached. Those who met the inclusion criteria were counselled on the aim and importance of the study. Those who granted consent were then examined and the data recorded on the data collection form. The data collection form had two main sections: the first section for the demographic variables and the second section for the crash and injury characteristics. We divided the days of the week to define week-days (from Monday to Thursday) and weekends (from Friday to Sunday). We also divided the 24 hours of the day as day time (6 am to 5:59 pm) and night time (6 pm to 5:59 am). The data was collected simultaneously in all the four hospitals in their emergency departments. It went on for 3 months. Patients who arrived in a critical state were examined later in the ward when they were much improved and stable.

Data collection, management and analysis
The data collected included: 1) patient's identification: name, age, sex, level of education, injury characteristics, time of the accident. a) Type of crash: motor-bike or car; b) Type of collision: bike-bike, bike-car, car-car, pedestrian-bike, pedestrian-car; c) Position of the victim: pedestrian, bike rider or passenger, car driver or passenger; d) Body part injured and nature of the injury.
2) Crash characteristics: date and time of crash, type of collision, position of the patient (rider, driver or passenger), rider's or driver's experience (license), helmet or seat belt use and the notion of alcohol consumption by rider or driver within 6h prior to the crash.
3) Lesions identified and recorded: Description of these lesions included identification of anatomical location, detailed description of the lesion, and estimation of Glasgow Coma Score when indicated. 4) Outcome in the emergency department: discharge, Inward admission, referral to another institution, or death in the emergency department. The data collected using the data collection forms were thoroughly checked for discrepancies. Data recorded was checked again for completeness before data analysis.
Simple illustrations like graphs, tables, measures of central tendencies and dispersion were obtained for the variables. The chi square test for independence and the fisher's test of significance were used where necessary to compare results. Epi Info software was used to analyse this data. Data was kept secret and all information was recorded in a computer protected by a password.

Ethical consideration
Ethical clearance was obtained from the Faculty of Health Sciences Institutional Review Board. An authorization was sought from the Regional Delegate of Public Health of South West Region.
Permission was obtained from the Directors of the Hospitals involved before the research was conducted. Participants received explanations on the goals of the research and why their collaboration was important.

Results
A total of 434 road traffic crash victims were received across all 4 hospitals during the period of the study. Twenty-three (5.29%) patients were excluded. Out of these 6 did not consent, 16 had incomplete data and 1 was declared dead on arrival. Thus we finally had a total of 411 crash victims to analyze. The age ranged from 2 to 80 years, with a mean age of 32.6 (± 15.6) years. 95% CI 31.1-34.1. There were 268 males and 143 females, giving a male to female ratio of 1.87:1. There were 197 victims with lower limb injuries giving a prevalence of 47.93%.

Demographic and social variables
Among the 197 patients that had lower limb injuries, 115 were males and 82 were females, giving a male to female ratio of 1.4:1.

Crash characteristics
The most common mechanism by which crash victims sustained lower limb injuries were: bike-car collisions (22.84%), and bikepedestrian collision (19.29%). Thus motor bikes (76.14%) were the most common cause of lower extremity injuries (p < 0.01) ( Figure   2).

Position of patients with lower limb injuries at the time of the crash
The most vulnerable road users were passengers on motorized two wheelers (43.65%) and pedestrians (31.47%) (Figure 3).

Most vulnerable road users per age group
Regarding the age groups, the three most vulnerable road users per age group are depicted in the table (in descending order) ( Table 1).
Regarding the day of the injury we noticed an increase in road traffic crash related injuries during festive periods or national day celebrations.

Road safety measures used
The road safety measures here were: helmet, seat belt, alcohol within 6 hours, drivers/ riders license. With regards to road traffic crash related risk factors, 20 (10.15%) admitted to bad roads as a related risk factor, while 10 (5.05%) pointed to bad weather as a related risk factor ( Table 2).

Pattern of lower extremity injuries
Regarding the side of the lower limb affected, the left lower limb 100 (50.76%) was generally more affected than the right 76  (Table 3).

Types of fractures
Open fractures 41(60.29%) were more common than closed Speed at which crash occurred: Regarding the reported speed of the transporter involved, fractures were most common at speeds above 60km/hr. 43(63.24%) ( Figure 6).

Discussion
Reports on epidemiological studies on lower limb injuries due to road traffic crashes are scarce. This study found a prevalence of lower extremity injuries in road traffic crashes of 47.93%. This high prevalence is similar to that found in another study in Cameroon [15]. This high prevalence can be attributed to the fact that the lower extremities are most often very exposed compared to other anatomical parts of the body. with an almost equal gender distribution. In general, there was a marked male predominance in our study. Males are by their nature more active and so more likely to get them injured than females Page number not for citation purposes 5 [16][17][18]. Lower limb injuries were most encountered (54.32%) in people in the active and productive age group (20 < 40) which correlates with other studies [16][17][18][19][20][21][22]. This is so because this age group comprises the active population and the main source of revenue and work force of our study area. They are more mobile, always moving between different locations by varied means of road transport and thus are most at risk of road traffic accidents.
Motorized two wheelers (68.37%) were the most involved mode of transportation in road crash collisions. Motorized two wheelers are almost becoming the main means of transportation in most Cameroon cities and rural areas. Little formal training of the riders on how to operate the motorcycles and disregard for traffic regulations constitute a major risk factor for accidents [23].
Passengers on motor bikes (44%) and pedestrians (31%) were the most vulnerable road users affected with lower limb injuries. This is contrary to a study carried out in Nigeria by [24] in which passengers in minibuses and drivers were most vulnerable [24]. This is attributed to the fact that motorized two wheelers are the main means of intra urban transportation in most Cameroon cities.
This large proportion of vulnerable road users is also explained by a traffic mix of incompatible users (pedestrians, cyclists, motorbikes, cars, and trucks) with, for example, communities living close to major highways, or the lack of pedestrian lanes along these highways [25].
Most previous studies describing the pattern of injuries in road traffic crash victims indicate a dominance of facial, extremity and head injuries [13,26,27]. This is similar to the findings we had with a marked high prevalence of head and lower extremity injuries. A very small percentage of these road users use the safety measures like helmets seat belts and little or no protective gear for the extremities. Decrease in the rate of use of protective measures reflects a lack of awareness of the role of these measures in preventing and reducing the severity of injuries.
There was a variation regarding the limb involved, the left limb (50.76%) was more affected than the right limb (38.58%, p > 0.05). A few patients sustained injuries on both limbs (10.66%).
This was similar to findings by other researchers, although this was not statistically significant [28,29]. In our study area, drivers and riders keep right, thus exposing the left half of the body to collisions with opposite flow traffic.
Fractures (34.52%) were the most common pattern of lower extremity injury sustained by road crash victims in this study, closely followed by lacerations (36.90%) and bruises (24.84%) [28,29].This is similar to other findings [24], but different from other studies in which bruises and abrasions were the most common [13,29].

Study limitations
Self-reporting: The accuracy of respondent's answer on the occurrence of injury events or on how injuries were acquired could not be independently verified.

Language difficulty: Not all patients were fluent in English or
French; this made it difficult for them to describe crash events in understandable manner. This might have affected our data collection. To fix this, we advised patients to use the language they were most fluent in and translators were sought in exceptional cases.
Study type: Being a hospital based study implied there was bound to be some under reporting of injuries as some of these patients would prefer to be treated locally or elsewhere. To reduce this, we had to select hospitals from all the stages of referral system. This will reduce under reporting and provide a clearer pattern of injury patterns, regardless of economic background and location.

Consent issues:
Not all patients were willing to give consent.
Others had incomplete data while some died at the crash scene. All these contributed to some degree of under reporting.

Conclusion
From our findings and in view of our study objectives, we come to the following conclusions: The prevalence of lower extremity injuries from Road Traffic Crashes in our study area was 47.93%. More males sustained lower extremity injuries than females, with a male to female ratio of 1.4:1, and the majority of the victims in our series were between the ages of 20 to 40 years old. In our series the left lower limb was more affected than the right and fractures were the most common type of injuries sustained (34.52%), followed by lacerations (26.90%),and bruises (24.87%). Associated risk factors to the road traffic crashes as identified by the victims were bad Page number not for citation purposes 6 roads (10.15%) and bad weather (5.05%). The safety gargets were not adequately utilized by our victims, with 87.72% confirming that they did not wear the helmet and 87.50% affirming that they did not wear the seat belt at the time of the crash. The occupations mostly affected in our series were pupils and students (20.3%) and business people (19.2%), then the bike riders (15.23%).
Our recommendation: Considering our findings we recommend the following to the road safety authorities and the general road  In our series the left lower limb was more affected than the right and fractures were the most common type of injuries sustained (34.52%), followed by lacerations (26.90%), and bruises (24.87%): associated risk factors to the road traffic crashes as identified by the victims were bad roads (10.15%) and bad weather (5.05%); the safety gargets were not adequately utilized by our victims, with 87.72% confirming that they did not wear the helmet and 87.50% affirming that they did not wear the seat belt at the time of the crash.

Competing interests
The authors declare no competing interests.

Acknowledgments
We are grateful to all who participated in this research.