Can ACL Tears be Restricted to Sports Injuries Alone? A Retrospective Analysis

Abstract

Background

The number of people injured following a road traffic accident (RTA) are as high as 2–5 crores around the world every year. The literature from western population suggests that ACL injuries are encountered mostly following high velocity sports injuries in clinical practise. But, in India there are a large group of individuals presenting with ACL injuries following RTAs.

Methods

We performed a retrospective analysis of all patients with ACL injuries presenting to our hospital following RTAs. All the information pertaining to the ligaments injured, vehicular factors, time of the day and environmental factors were recorded. The data was then analysed statistically.

Results

Most injuries occurred in the 31–40 year age group and velocity in the same range. Injuries due to bike skid predominated in our study amounting to 55.9%. Interestingly, very low velocities accidents due to stray dogs accounted to 43.8% and they occur mostly at night.

Conclusion

The number of patients presenting with RTA related ACL injuries in our country are numerous. Hence, we have made an attempt to show that ACL injuries can occur even at low velocity following motor vehicle accidents in contrast to the western population, where sports related injuries are the most common etiology for such mishaps.

Introduction

Motor vehicle accident injures 2–5 crore people around the world, and at the same time kills nearly 13 lakh individuals each year. World Health Organization (WHO) has stated that for people in the age group of 15–29 years, it is the leading cause of fatality. It is envisioned that vehicular crashes will climb as the top five prominent causes of death by the year 2030 [1].

Meanwhile, India has emerged as a top nation in the number of deaths following road accident deaths among the 199 Countries. This was reported in the World Road Statistics, 2018. In the year 2018, a mammoth total of 4,67,044 road traffic accidents have been reported by States and Union Territories (UTs) which claimed 1,51,417 lives and caused injuries to 4,69,418 individuals. Among these two-wheeler accidents were 1,64,313 which amounted to 35.2% share, among accidents caused by other vehicles [2].

There is meager data regarding analysis of two wheeler accidents occurring specially in the Indian subcontinent. Each month on an average nearly 38,920 individuals meet with an accident out of which 12,618 people die every month [2].

Anterior cruciate ligament (ACL) is one of the most common ligaments injured world-wide with an annual incidence of under quarter million cases. A predicted number of about 70% of ACL injuries are sustained through noncontact mechanisms, while the remaining 30% result from direct contacts [3].

It is quite evident that ACL injuries in the western population are mostly due to sports activities or domestic falls [4]. But in the Indian population vehicular accidents depict a distinct number of ACL injuries which have been rising over the past few years [2].

The attempt to curb road traffic accidents as well as implement road safety measures is the need of the hour. Hence, since there is little or no statistics pertaining to road traffic accidents leading to knee ligament injuries, we have enlisted numerous parameters to record the data of these patients at our Institute. The prime focus was involvement of ACL apart from the other ligamentous and bony structure injuries around the knee.

Here, we present results of the analysis of incidence of ACL and related knee injuries following two-wheeler accidents in India and the circumstances which lead to the accident. Hence, we have made an attempt to propose a few preventive measures which can be imposed so as to avert the chances of knee injuries and hence curtail morbidity and mortality rates and in-turn reduce loss of work hours and reduced quality of life.

Materials and Methods

A retrospective observational study of all patients who had reported to our Hospital between January 2014 and January 2019 was done. The patients taken into our study were ACL and related injuries following motor-cycle related accidents (group 1). The remaining set of individuals affected by non-RTA related ACL injuries due to sports related and domestic fall were classified as group 2. The diagnosis was confirmed radiologically using 1.5 T MRI scan. A written informed consent was obtained from each patient. Inclusion criteria were cases with ACL injuries solely or associated with other ligaments following RTA were included. Exclusion criteria were poly trauma cases, open fractures in the ACL injured limb, head injury patients and pediatric age groups.

The patient’s data sheet was recorded with respect to the ligaments injured (ACL, PCL, PLC, MCL, LCL and ALL) and anatomical sites of chondral defects (femur, tibia and patella). Additionally, other parameters such as type of vehicle (geared or non-geared), speed (in km/h) preceding the collision. If the patient was the driver or pillion rider, accidents due to direct collision (two-wheeler vs two-wheeler, two-wheeler vs four-wheeler and stray animals such as dogs, cats or cows), skidding and falling because of slippery roads, pot holes or other factors and infrastructure of the road (gravel, muddy or tar road). A separate column for contact and non-contact injuries were also collected.

Mishaps occurring because of direct collision with two-wheeler vs two-wheeler, two-wheeler vs four-wheeler, pedestrians, stray animals such as dogs, cats or cows and crash against a wall or sign boards were classified under contact injuries, while those accidents due to skidding from two-wheeler, pot holes, slippery roads and loss of balance were included in non-contact injuries. Furthermore, the injuries occurring during the day and night were recorded. Day was considered as cases from dawn to dusk (on an average 6.30 AM to 6.30 PM) and night was during the remaining hours.

The data were entered in an excel sheet and was analysed using the SPSS software. The basic demographic variables were expressed as percentages and the association between various factors contributing to the cause (ACL tear) was analysed using Chi-square test. Finally, if the p value was < 0.05, it was considered as statistically significant.

Results

A total of 2138 cases pertaining to ACL injuries presented at a single Centre were retrieved, of which 745 cases (34.8%) alone were categorized in group 1 and the rest 1393 cases (65.1%) were in group 2. A total of 508 cases which had complete data were included in the study and the remaining 237 cases were excluded as they either did not fulfill the criteria or there was insufficient data. All the patients met with accidents within the State of Tamil Nadu, India (Fig. 1).

Fig. 1.

Pie-chart showing distribution of various cases in our study pool

Gender

Male dominated with 406 patients and female cases were 102.

Side Dominance

Maximum cases of right sided injuries were noted (n = 289, 56.8%), while the number of left sided knee trauma cases were 219 (43.1%).

Age

The age distribution was done. Those below 20 years and above 60 years of age, and with a confidence interval of 10, the intermediate age groups were classified. Most of the cases were in 31–40 years (n = 177, 34.8%) and the least belonged to the elderly population above 60 years (n = 8, 1.5%). A little more than a dozen individuals were noted below 20 years of age (n = 15, 2.9%).

Velocity

The speed of vehicles was classified with differences of 10 km/h confidence intervals from 30 to 60 and beyond 60 km/h. This was further sub-classified into very low velocity (< / = 30 km/h), low velocity (31–40 km/h) and high velocity (> 40 km/h). Maximum number of cases were noted in the 31–40 km/h group amounting to 288 cases (56.7%) (Fig. 2).

Fig. 2.

Bar chart illustrating distribution of cases according to velocity (km/h)

Mode of Injury

There were four main modes viz. two-wheeler vs two-wheeler, skidding and falling, stray animal related accidents and two-wheeler vs four-wheeler. Injuries due to skidding were on top of the list, 284 cases (55.9%) and these occurred mostly at 31–40 km/h velocity (n = 189, 37.2%). At higher velocities, i.e.,  > 40 km/h injury occurred mainly due to either two-wheeler vs two-wheeler or two-wheeler vs four-wheeler collisions (combined n = 90). It is interesting to note that at very low velocity, accidents due to stray animals showed a significant percentage of 43.8% (n = 21). However, we did not come across any injuries due to pedestrians (Table 1).

Table 1.

Mode of injury vs velocity (km/h)

Mode of injury	Velocity (km/h)					Total
	< 30	31–40	41–50	51–60	> 60
Two-wheeler vs two-wheeler	6	51	47	15	0	119
Skid	21	189	72	1	1	284
Stray dog	21	48	8	0	0	77
Two-wheeler vs four-wheeler	0	0	1	27	0	28
Total	48	288	128	43	1	508

Diurnal Variation

An enormous number of 346 cases (68.1%) were documented to have met with road traffic accident during the daylight (Table 2). Most of these cases were in the range 31–40 km/h (n = 201, 39.5%). However, at very low speeds (total cases = 48), 60.4% cases (n = 29) were seen during the night (Table 3). During the day (Table 4), injuries due to skidding were most prevalent (n = 201, 39.5%) and most of them clocked at 31–40 km/h (n = 141, 27.7%). A vital point to note is that injuries due to stray dogs still remained maximum (n = 10) even during the day at very low velocity (Table 4). The data during night showed a similar trend as day with ACL tear due to skid (n = 83, 16.3%) followed by trauma due to stray dogs (n = 44, 8.6%); total cases at night were 162 (Table 2). A clear attention can be drawn towards stray dog related trauma which happened mostly in the night (n = 44, total = 77) (Table 2).

Table 2.

Diurnal variation vs mode of injury

Time of day	Mode of injury
	Two-wheeler vs two-wheeler	Skid	Stray	Two-wheeler vs four-wheeler	Total
Day	88	201	33	24	346
Night	31	83	44	4	162
Total	119	284	77	28	508

Table 3.

Diurnal variation vs velocity (km/h)

Time of day	Velocity (km/h)
	< 30	31–40	41–50	51–60	> 60
Day	19	201	88	37	1	346
Night	29	87	40	6	0	162
Total	48	288	128	43	1	508

Table 4.

Mode of injury vs velocity (km/h) during the day

Mode of injury (day)	Velocity (km/h)
	< 30	31–40	41–50	51–60	> 60
Two-wheeler vs two-wheeler	5	44	26	13	0	88
Skid	4	141	54	1	1	201
Stray dog	10	16	7	0	0	33
Two-wheeler vs four-wheeler	0	0	1	23	0	24
Total	19	201	88	37	1	346

Periarticular Structures

The other ligaments around the knee which were injured were grouped under “other ligaments”. Category, so as to help in statistical evaluation, 117 cases with various ligaments were injured. These patients were dominant in the category of 31–40 km/h which was 46.2% (n = 54). A striking information to note was at very low velocity, a significant number (n = 25, P < 0.05) of patients were having concomitant multi-ligament injuries.

Contact/Non-contact Injuries

Contact accidents (n = 255, 50.1%) were almost similar to non-contact (n = 253, 49.8%) and most of them were in the high velocity category (n = 122). The non-contact injuries were maximum in 31–40 km/h range (n = 244) and were due to skidding.

Driver/Pillion

Drivers who ended up with injuries were maximum (n = 446, 87.7%) and they occurred mostly due to skidding and falling (n = 236). Pillion riders were meager in count (n = 62, 12.2%) and they too were injured because of two-wheeler skidding and falling.

Road Construction

Tar road were on top of the list with 374 (73.6%) cases causing knee injuries. This was followed by muddy roads with 133 patients. Finally, one case met with an accident on road made of gravel. The injuries occurring on tar roads were mainly due to skidding and falling (n = 202). However, stray dog related injuries were almost comparable on tar roads (n = 41, 8%) and muddy roads (n = 36, 7%).

Model of the Vehicle

Geared motorcycles had maximum injuries amounting to 388 (76.3%) followed by non-geared vehicles which were 120 cases. Moreover, at high velocities geared vehicles had maximum accidents (n = 131, 25.7%).

Discussion

Over the course of many decades several studies have been done on the incidence and mode of injury to the ACL. Most of them have proved that damage to the ACL is caused mainly due to Sports [5]. On the contrary, in our study we have learned that in the Indian context, vehicular collisions contribute significantly towards injury to ACL and other knee structures. The after effects of ACL injury include not only temporary but in some cases, even permanent disability which incurs a significant cost to patients [6]7. Hence, there is a growing need to take effective measures to avert the sizable number of RTA related ACL tears.

In 2018, the WHO issued a Global Report on Road Safety, stating that, India accounts for nearly 11% of the accident related casualties in the world [2]. The transportation of freight and passengers in India is preferred by road. The rapidly bursting population, remarkable growth in the use of motor vehicles coupled with rising urbanization has made people vulnerable to incessant RTAs resulting in mortalities and morbidities [8] 9.

The highest number of RTAs in India were recorded in the State of Tamil Nadu (63,920) which amounts to 13.7% of share 2018 [2]. Our study consisted of patients from this region with utmost attention given to ACL injuries along with other parameters as mentioned previously. The total number of cases were 508, in which all the victims were travelling on a two-wheeler. According to the Indian statistics published in 2018 [2], two-wheeler accidents ranked as the largest share with respect to RTAs (35.2%), total number of individuals killed (31.4%) and persons wounded (32.7%). One among the ample factors may be a considerable increase in the vehicle density (number of vehicles per km of road) which was recorded to be 42.95 as compared to the data in 2010 which was nearly half (27.88) [2]. Besides, in terms of vehicular composition on road, two-wheelers contribute to about 70% and hence there is an absolute need to focus on safety related to this segment of vehicles.

The 2018 data in India showed maximum RTAs among youngsters (20–45 years) [2] and a similar trend was seen in our study, where ACL injury following RTA was highest in 20–40 years (n = 349). They belong to the economically active age group and hence are predisposed to injuries [1]. Gender distribution was dominated by men (86%) and this corroborated with our results of masculine population (79.9%). World-wide the incidence of men being victims of RTAs has been maximum [10].

There are various modes of injuries among which mishaps due to skidding and falling were maximum in our study (n = 284, 55.9%) followed by vehicle to vehicle collision (n = 119, 23.4%). Conversely, Indian statistics [2] showed that direct collisions constituted to 52.02% injuries.

Vehicular collisions are the result of interplay between plentiful factors, which can be broadly categorized as, human errors, environmental conditions, road construction and vehicular condition. Human factors which constitute to almost 75% [2], outnumber all other causes. In our study, there were 147 cases (28.9%) of injuries due to direct collision (two-wheeler vs two/four-wheeler). Inclusion of skidding and falling under the same category falls in the grey zone, as such, mishaps can occur due to multiple reasons as mentioned earlier. But, reckless and drunken driving do result in RTAs [2]11 and according to the statistics in 2018, accidents due to the former were responsible for majority cases. We found that 73 cases (14.3%) that met with an accident due to skidding and falling were in the high velocity range.

In our study we have found that most of the cases (56.7%) were in the range of 31–40 km/h (low velocity). A similar presentation in 39th Orthop aedic World Congress SICOT, Montreal 2018 was done by Kerketta et al.[12]. They performed a study with a smaller sample size and their main aim was to study the incidence of ACL injuries in low velocity two wheeler RTAs. They concluded that most of the injuries were in the same velocity range as our study and the individuals predominated in the 20–40 year age group. In addition, they also mentioned a limitation of lesser sample size (n = 50) in their study.

Next, road environment plays a pivotal role in causing RTAs in our Country. One of the main reasons for this being weather conditions that mainly influence the condition of roads leading to their early wear and tear. The other causes include, tapering roads, faulty configuration of crossroads, ineffective lighting and poor design. Many of the contractors in India are either inexperienced or are focused on personal gain which subsequently results in establishment of unsafe roads having several ditches and pot holes [11]. The research conducted by us constituted more than half of our sample size (n = 284, 55.9%) due to skidding and falling. This category included crashes occurring due to pot-holes in addition to other causes enlisted. With regards to composition of road, we had 26.2% cases (n = 133) which took place on muddy roads. This indicates that bad roads form hurdles to smooth travel and consequently lead to ACL injuries.

Climatic conditions predispose to RTAs and are unpredictable factors. The pendulum of increased rate of accidents is swayed in an ascending direction due to slick roads combined with poor visibility making driving unpropitious to travelers [1]. However, a record of weather conditions was not noted in our datasheet and this is one of the limitations of our study.

Daylight improves visibility and can help ameliorate chances RTAs. But at the same time the confidence to rev up a motorcycle equally surges and hence, piles up the already mammoth cases of RTAs. The census in 2018, revealed that 6 PM to 9 PM accounted to 18.6 of RTAs followed by 3 PM to 6 PM and this pattern has been persistent in the preceding 5 years [2]. Our analysis showed that cases in the day peaked to 346 (68.1%). Most of these cases were in the low velocity range (n = 201). A striking information at very low velocity cases in the night rose to 60.4% (n = 29) and this may indicate that due to lesser visibility the drivers may be more cautious. Moreover, stray animal accidents were highest at night (n = 44) which all the more proves that these creatures create a nuisance to people travelling on the road.

Maintenance of vehicles in good condition also plays a crucial role in the occurrence of RTAs. A well-oiled automobile can help avert an ACL injury at the primordial level [1]. In addition, geared vehicles assist in revving a two-wheeler to higher speeds and we had 76.4% cases (n = 388) in our study. But, this cannot be concluded that non-geared vehicles have fewer chances of meeting with mishaps.

Therefore, keeping in mind the ACL injuries occurring at an enormous rate, it is incumbent to act upon mitigating their rates. The government plays a humongous role to scale down the incidence of RTAs and hence shrink the number of ACL injuries. We have framed several preventive strategies that can be imposed so as to lower the rising cases of RTAs.

Preventive Measures

The foremost factor which needs emphasis is to decrease the exposure to risk. Empiric data signifies that on an average rise in speed of 1 km/h is linked with a 3% higher risk of a RTA resulting in an injury [13]. Risk occurs due to a person’s need to travel which can be for official reasons or entertainment purposes. Thus, there is a need to bring down the number of people commuting long distances especially for monetary gains and this can only be achieved by advocating necessary actions to boost local economy and create surplus job opportunities. Besides, abundant establishments relating to leisure can be erected which will in-turn shrink the risk of RTAs.

There is an inexhaustible list of precautionary measures but we have enlisted a few points with regards to our study.

• Improvement of infrastructure such as adequate road lighting, use of neon paints to demarcate the road lanes and use of neon lights, fixing of road fencing to prevent animal crossing and planting speed limit sign boards.

• Enforcing stringent laws so as to limit vehicular speed on highways and accomplishing this by surveillance using road-side cameras.

• Regular set-up of traffic police check posts so as to assist in strict implementation of traffic laws.

• Using state-of-art devices such as drones for effective surveillance of hilly areas.

• Involvement of animal activists and stray dog detection teams.

• The mixed composition of vehicles on roads has caused a nuisance leading to RTAs. To put it differently, the same road is used by various motorized and non-motorized vehicles, and at varied speeds. The exposure to risk can only be reduced by enforcing rules and regulations and separating vehicles according to their velocities.

• Ministry of road transport and highways has passed the Motor Vehicle Amendment Act 2019. The essence of this act is on road safety which includes several measures such as, heavy fines for traffic violations, high-tech use of vehicle fitness and driving tests etc. [2].

Preventive measures
Improving the framework of roads
Implementing strict laws
Modern technology for road surveillance
Control of stray dogs

Limitations of the Study

• The history pertaining to consumption of alcohol, intake of drugs, while driving and possession of valid driver’s license was not recorded.

• An important information regarding the position of the limb and knee joint at the time of injury could not be documented as the patients were unable to recollect this subtle but vital information.

• The patients could not recall the exact speed of the vehicle at the time of the accident and hence, an arbitrary value was taken based on the vague information provided by them.

• A record of the road categories such as, National, State and other Highways was not listed in our study.

• We did not pay significant focus on the weather conditions at the time of trauma, since this was a retrospective study data pertaining to this was not recorded.

However, one deduction can be that in Tamil Nadu (India), where the accidents occur almost March–July consists of summer, while the remaining months the climate is unpredictable with phases of moderate rainfall.

• A far larger sample size especially at a national level is needed to study the variation of knee ligament injuries and hence implement necessary measures.

Conclusion

The morbidity associated with ACL injuries is disabling and when these mishaps occur due to road traffic accidents, it can be disastrous. Though some of the factors leading to these mishaps are preventable, the effective implementation needs tremendous amount of efforts from individual level to the government authorities. In this manuscript, we have combined the orthopedic and preventive medicine point of view in averting the chances of ACL injuries. This is particularly important as the State of Tamil Nadu ranks highest among RTA related injuries and ACL injury is one among them. The effective implementation of preventive measures as listed can contribute to a large extent towards a decline in RTA related knee ligament injuries.

Compliance with Ethical Standards

Conflict of interest

On behalf of all authors, the corresponding author states that there is no conflict of interest.

Ethical standard statement

This article does not contain any studies with human or animal subjects performed by the any of the authors.

Informed consent

For this type of study informed consent is not required.