Introduction
Rugby union is one of the most played and watched sports in the world with more than five million rugby players worldwide,1-3 being reported a player yearly increase of 19%.4 In Portugal, a growing interest in rugby union has been also witnessed by all agents involved.5,6) Due to its nature as a contact sport, there is an increased susceptibility to the occurrence of traumatic injuries, particularly in the shoulder joint.3
Most studies report shoulder injury incidence to range from 2.3 to 13 per 1000 player match-hours at amateur and professional level, respectively.3,7 Reported mean severity is also high and reaches 9.4 weeks for amateur players and 52.6 and 41.1 days for professional forwards and backs, respectively.7-9
It is also know that only 6% of all traumatic injuries in rugby union are caused by foul plays10) and that their natural appearance is a result of normal gameplay.11,12 Shoulder is one of the most frequently injured joints both in amateur and professional rugby union13 and it has been reported that between 49% and 72% of all injuries occur on the event of tackling or being tackled.9,14-16
The aim of this study is to report the incidence of traumatic shoulder injuries sustained by a group of top-tier Portuguese Rugby Union players, and to characterize some relevant epidemiological aspects.
Method
Sample
A total of 51 Portuguese senior male rugby players (age: 22.10 ± 4.59 years; body height: 1.79 ± 0.05 m; body mass: 88.06 ± 13.74 kg) were included in our study. The study conformed to the standards set by the Declaration of Helsinki. Players were informed about the procedures, potential risks and benefits of the study.
Procedures
A cohort prospective study was conducted, between September 2013 and May 2014, monitoring the incidence of shoulder injuries occurred in a group of Portuguese Rugby Union players, playing in the same team in the top-tier of the Portuguese Rugby Union National Championship (Divisão de Honra).
The Portuguese Top-tier National Championship is a ‘round-robin’ tournament with the top six teams qualifying to a final play-off. In the case of the team included in our study, the total number of matches played during the 2013/14 season was nineteen. Therefore, the total match exposure time of players in hours (given by NmPmDm/60, where Nm is the number of matches played, Pm is the number of players in the team and Dm is the duration of the match in minutes)15 was 380 player match-hours.
The protocol involved the immediate report of all suspected shoulder injuries by the medical staff of the team to the researchers (all medical practitioners), who then would assess the player. All injured players were followed until their return to practice without limitations.
Data was collected and recorded according to the consensus statement for epidemiological studies in rugby union.15,16 Information was retrieved regarding: the position of the player; the type of injury sustained (muscle, contusion, dislocation, joint or fracture); if the injury was preceded by contact with the opponent or not; if this was a new or recurrent injury; the number of days the player was absent from practice and/or training.
Statistical analysis
We report injury incidence as injury/1000 player match-hours (95% confidence interval — CI) and severity as mean (±standard deviation — SD) days. For continuous variables, normality was assessed using Shapiro-Wilk. As continuous variables were normally distributed, Student's t-test was used to compare the severity of injuries between positions, and recurrent versus non-recurrent injuries. Statistical significance was accepted at p < 0.05. Descriptive and inferential analysis was performed using SPSS® v20.0.
Results
A total of nine shoulder injuries sustained during matches throughout the 2013/14 season were reported for rugby players of the team included in our study. Data is summarized in Table 1. This represents a total injury incidence rate of 23.68 per 1000 player match-hours (95% confidence interval — CI: 11.70-43.23). Only one of the injuries was reported as mild (causing an absence of less than 7 days to practice or training), four were considered moderate (absence ranging from 8 to 28 days) and four severe (absence greater than 28 days).
Case | Position | Type | Contact | Recurrent | Severity (days) |
---|---|---|---|---|---|
1 | Forward | Joint | Yes | No | 60 |
2 | Forward | Joint | Yes | No | 60 |
3 | Forward | Joint | Yes | Yes | 7 |
4 | Forward | Joint | Yes | Yes | 10 |
5 | Forward | Joint | Yes | No | 21 |
6 | Back | Joint | Yes | No | 35 |
7 | Back | Joint | No | No | 21 |
8 | Forward | Dislocation | Yes | No | 10 |
9 | Forward | Joint | Yes | No | 84 |
Seven of the injuries were sustained by forwards, and only two by backs, leading to different injury incidence rates: 34.54 per 1000 player match-hours (95% CI: 15.40-67.82) for forwards, and 11.27 per 1000 player match-hours (95% CI: 2.25-36.15) for backs, as it can be seen in Table 1. Mean severity of injuries was 36.00 (±31.28) days for forwards, and 28.00 (±9.88) days for backs (see Fig. 1), but no significant statistical differences were found between the two groups (p = 0.581), with a global mean severity of injuries of 34.22 (±27.55) days.
It was also noticed that seven of the injuries were new and two considered to be recurrent. The mean severity reported for recurrent injuries was 8.50 (±2.12) days, while for new injuries, mean severity was of 41.57 (±26.97) days (see Fig. 2). Regarding these differences, a statistical significance was found (p = 0.017) with new shoulder injuries causing greater absence from practice or match, when compared to recurrences of old injuries.
It is important to notice that, as expected, eight of the nine injuries were sustained after contact with the opponent. Regarding the type of injury, and according to the consensus statement for epidemiological studies in rugby union,15,16 eight of the injuries were classified as ‘Joint/ligament’ and one as ‘dislocation’.
Discussion
Considering the incidence of shoulder and upper limb injuries in senior men's professional rugby union (26-84 per 1000 player match-hours)3 it is clear that our population presented results within the expected parameters (23.86 per 1000 player match-hours), despite the theory presented by some authors that claim that a greater incidence of injury occurs in higher levels of play.13,17,18
The mean severity of injuries was 34.22 (±27.55) days, a value higher than expected when comparing with other studies11,15 showing mean severity of injuries for forwards to be 21.2 versus 36.00 (±31.28) in our study, and for backs 26.2 versus 28.00 (±9.88) days in our study.
Our results also show that new injuries are significant and are associated with higher mean severity. This finding is also consistent with the literature that considers the average severity of new injuries to be higher. Reported mean severity of 41.57 days in new injuries versus 8.50 days in recurrent injuries alerts us for the importance of preventing measures. Higher level of physical preparation, adequate warm up and the use of protective equipment may help in the prevention of in game shoulder injury.
As limitations of this study we find that a larger number of players and injuries could lead to stronger statistical power, as well as more seasons of follow up to assess with greater certainty the results obtained.
In the light of these results, the authors believe that the rehabilitating support offered in the professional level might play an important role when treating and rehabilitating an injured player. It is of the utmost importance an early and directed individual rehabilitation program in order to achieve a faster and satisfying result.
When comparing our results with other studies that report shoulder injuries, the authors believe that the physical condition and faster exhaustion of the players contributed to the increased number of shoulder injuries of our target population. Specific training programs, to improve muscle strength and technical training, to improve correct technical aspects of the tackling interaction, during the fatigue periods of the game, could be paramount in the prevention of shoulder injuries. It is the author's opinion that more prospective studies, involving specific training programs, are needed in order to better understand the role of physical conditioning and specific muscle strengthening programs, in the prevention of primary and recurrent shoulder injuries during rugby matches.