Hockey injuries across the lifespan: a descriptive, population-based study.

INTRODUCTION

As a sport, ice hockey is a dynamic and demanding activity. The pace at which hockey is played stresses the development of motor coordination, speed and strength among its players. [1] As characterized by Sim and Chao (1978), hockey is a sport which is played on knives (skates), with clubs (sticks) and bullets (pucks). [16,21] Contact with the bladed edge of a skate, hockey stick, or puck can result in significant trauma to players.

At the elite levels, physical play is also seen as a fundamental part of the game. [15] Used primarily as a defensive tactic, "body checking" is defined by Hockey Canada as a technique whereby a player may legally separate a player from the puck through forceful body contact. Contact can come from the side, front or diagonally, but contact from behind is prohibited. [13] Body checking has been cited by several researchers as a primary cause of hockey related injury. [9, 15, 16]

A meta-analysis of hockey injury literature conducted by Benson and Meeuwisse (2005), found that the most common types of injuries among competitive hockey players [less than or equal to] 20 years old were: contusions, sprains/strains, lacerations, concussions and fractures. [2] In adult recreational leagues (i.e. [greater than or equal to] 18 years old) where player contact is not allowed, it was found that players in the Adult Male Recreational Leagues and Old-Timers Leagues reported injuries to the lower extremity as being the most common site of injury; accounting for 34% of all injuries. [23]

Previous Hockey injury investigations have focused primarily on fairly small samples of hockey players within a definable age range [6,7,9,13], sex [3,20], or ability level [22-24], or a combination thereof. What is lacking are large scale, population based analyses detailing the risk factors associated with hockey injuries.

Objectives

The primary objective of this investigation is to describe the epidemiology of hockey injury in Ontario Canada from 2004-2006. This includes an analysis by age group, sex, body part injured, and mechanism of injury.

METHODS

Subjects

All hospitals in Ontario report Emergency Department visit and hospitalization data to the Ontario Ministry of Health and Long Term Care. The National Ambulatory Care and Reporting System (NACRS) and Discharge Abstract Database (DAD) are two routinely collected administrative databases, directed by the Canadian Institute for Health Information (CIHI).

The NACRS database includes data submitted by all emergency departments in the province, as well as day surgery and outpatient clinics. The DAD contains similar health care data for patients who were admitted to hospital. Access to anonymized records within NACRS and the DAD was granted by CIHI. Research ethics approval was granted by York University, Toronto, Canada.

The definition of a hockey injury was according to the Canadian edition of the International Classification of Disease Codes; tenth revision (ICD-10 CA), published by the World Health Organization. [12] Four codes encompass all broad mechanisms of hockey injury (Table 1).

Patient data submitted to the Ontario Ministry of Health and Long Term Care is processed and standardized to according to ministry guidelines; thereby minimizing variation in coding methodologies. The data sets (NACRS and the DAD) contain demographic information including the patient's age, sex, body part injured, and mechanism of injury. With respect to the type of injury sustained, classification proceeded according to ICD injury codes (e.g. S82.300 = distal fracture of the Tibia). [12]

Data Analysis

Frequency distributions for age, sex, mechanism of injury and body region injured were tabulated. Age cohorts were defined by 5 year intervals. However, the youngest ([less than or equal to] 9 years old) and oldest patients ([greater than or equal to] 55 years old) were collapsed into wider ranges because of low numbers at either end of the age spectrum. The division of body regions were made according to accepted anatomical principles. For instance, the upper extremity was divided into two sections: structures proximal to the elbow (i.e. the shoulder, arm and elbow) and structures distal to the elbow (i.e. the forearm, wrist and hand). The distribution of all variables by mechanism of injury was also examined. All data were analyzed using SPSS 15.0.

RESULTS

There were 53,843 emergency department visits and 928 hospitalizations for hockey injuries over the two year period (2004 to 2006) in Ontario resulting in an average annual incidence rate of 489.4 per 100,000 population for ED visits and 8.13 per 100,000 population for hospitalizations.

Frequency distributions for sex and age of patients in the DAD (inpatient) and NACRS (outpatient) are presented in Table 2. Most hockey injuries are incurred by males, representing over 90% cases among both NACRS and the DAD. With respect to age group and hockey injury, over 50% of patients admitted to hospital, and approximately 60% of injuries among outpatients were [less than or equal to] 19 years old.

The distribution of hockey injury by mechanism of injury is presented in Table 3. With respect to the DAD, approximately 84% of injuries requiring admission to hospital resulted from contact injury mechanisms. Among outpatients, the corresponding number is 61%.

Table 4 illustrates the frequencies of hockey injury by body region. Hockey injuries to the head and face among outpatients totalled 18,246 (33.89%) cases, representing the most frequent body region injured among outpatients. With respect to inpatients, Knee/Leg/Ankle/Foot injuries represent the greatest proportion of injuries by body region, with 280 (30.17%) of injuries.

Findings from the analyses of mechanism of injury and the other variables are presented in Tables 5 and 6 (representing outpatients and inpatients respectively). Covariates such as sex, age and injury location were cross-referenced by their injury mechanism to yield the number of injuries within each variable. For example, the number of males incurring hockey puck impact injuries in NACRS totalled 8,377; representing 17.1% of all male hockey outpatient injuries.

Patients [greater than or equal to] 50 years of age display more from a hockey puck impact injuries, than players in other age groups. Among outpatients, of the 1476 injured players 50 years and older, 516 (35%) sustained hockey puck impact injuries.

DISCUSSION

The findings of this investigation provide a unique examination of ice hockey injuries across the lifespan. Previous investigations studying the epidemiology of hockey injury, tended to examine injury incidence and prevalence among specific hockey playing populations (e.g. hockey teams or leagues). [6,9,24] While these studies have provided important information about risk factors they are limited by the scope of their study population. Hockey injuries occurring outside structured competitive play are often not captured or studied. This investigation, using standardized hospital injury surveillance records, has captured all incidents of hockey injury presenting to Ontario hospitals occurring in both organized and recreational play.

Many of our findings are consistent with previous research. The majority of hockey injuries among both outpatients and hospital admissions are incurred by males. This observation coincides with findings published by Hostetler et al. who reported that female hockey injuries represented approximately 10% of the total number of hockey injuries observed. [11] Additionally, Ontario hockey injury hospitalizations in 2002/2003 saw 453 males compared to 34 females hospitalized for hockey injury. [8] The large disparity of hockey injury occurring between males and females may be attributed to several factors. Most notably, more males play hockey than females. Hockey Canada reports that for the 2004/2005 hockey season, of the total 209,978 players registered in the Ontario Hockey Federation, 182,028 (87%) players were male. [10] Further, there is no contact play allowed within women's leagues, which makes them less likely to suffer a contact injury.

The proportions of hockey injuries occurring across age groups indicate that the majority of hockey injuries are being incurred by players [less than or equal to] 19 years old. Among outpatients, players 10-19 years old account for the majority of hockey injuries. This may be attributed to the more intense level of play and inclusion of contact play among players within this age group. It may also reflect a population that plays hockey more frequently. Previous research [2,6,24] has also noted that exposure time to hockey and physical play is greatest within this age range. Additionally, recognizing that the adolescent growth spurt among boys and girls attains peak velocity at age 10-14 [14], disparities in anthropometric measures among players are apparent. For instance, in Bantam league hockey players (i.e. 14 years old), the differences in height and weight between the largest and smallest players were reported as being 55cm and 53 kg respectively. [4] This in turn can translate into differences of skating speeds of 2.3 m/s and impact force generation differences in excess of 357%. [16]

The effects of the substantial variations in body stature among players in this age cohort, may be echoed in the results of the analysis examining the injury characteristics surrounding contact with another player (i.e. W51.02). Players 10-19 years old display the highest proportions of injury resulting from contact with other players. Further, a large proportion of injuries requiring inpatient treatment resulted from contact.

Of the other mechanisms of injury studied in this investigation, those resulting from stick and puck impacts presented clear age-associated influences. Specifically with reference to injuries resulting from stick impacts, it was found that players [less than or equal to] 9 years old have the highest percentage of stick injuries. This may be because younger players are relatively unskilled, and may have difficulty controlling their sticks or adhering to the no "high-sticking" rule in hockey. Thus, coaches and parents should encourage the development of strong stick handling skills as a means of reducing injuries resulting from wayward sticks.

Contrary to the risk profile for injuries due to hockey sticks, the risk of sustaining a hockey puck impact injury increases as players' age. With respect to puck injuries by body region, the Head/Face demonstrated the second highest frequency for injury. Relating this observation back to age and ability level, it may be that as age increases, skill increases. This increase in skill can manifest itself in terms of increasing puck velocities from shooting actions. Playing in leagues where players are not required to wear mandatory facial protection (i.e. [greater than or equal to] 18 years old), this lack of protection, combined with faster puck velocities may account for the increasing risk of injury from puck impacts to older players.

CLINICAL IMPLICATIONS

Hockey is a challenging sport which emphasizes speed, agility and strength. As a result of the dynamics of the game and the implements used, the potential for injury must be recognized. Some injuries (e.g. puck impacts) may be hard to prevent. Proper instruction and use of proper protective equipment may represent a method which can reduce the occurrence of these types of injuries.

The prevention of contact injuries in hockey is much more controversial. It has been argued that physical play is a fundamental and inseparable part of hockey. This contention certainly holds at the elite levels of performance. What can be re-evaluated is the minimum age at which physical play is introduced to players. The majority of Canadian leagues permit body checking among players 11-12 years old. However, the province of Quebec, does not allow body checking until the age 14. [13,17] After this age level, anthropometric differences between players are reduced. [19] Therefore, players may be better able to absorb and tolerate impact forces sustained as a result of physical play. It can also be hypothesized that delaying the introduction of physical play among youth players, can reduce the exposure time to contact injury, while allowing for a prolonged focus on technical skill development (e.g. stick handling). Future research is needed to explore these hypotheses.

Other injury prevention strategies which can be effective are education programs aimed at increased safety conscious behaviours among players. Past programs such as the "Smart Hockey" program instituted by The ThinkFirst Foundation of Canada, was effective in increasing safety conscious behaviours among its participants. [5] Adult players may benefit from an increased awareness of the consequences of ocular or facial injuries resulting from hockey. This in turn may promote the inclusion of a facemask as a standard protective device.

LIMITATIONS

As this study was an investigation into hockey injuries within Ontario, the results may not be generalizable to other populations. Further, no information was available regarding the context of injuries sustained by patients (e.g. organized versus unorganized hockey). This study only included hockey injuries which presented to hospital. As such, hockey injuries which were treated by a patient's doctor or those which never sought medical attention were not captured.

CONCLUSION

Hockey is a popular sport; it is played for fun and physical activity. Injuries sustained by players can be prevented by the amendment of rules, usage of proper equipment, or proficient execution of skills. However recognizing that hockey is a contact sport, there is an element of risk. A reduction in preventable injuries is a desirable outcome for players, regulatory bodies and the medical community.

REFERENCES

[1.] Benson B.W., Meeuwisse W.H. Ice Hockey Injuries. Med Sci Sports Exerc 2005; 49:86-119.

[2.] Benson BW, Meeuwisse WH. Ice Hockey Injuries. Med Sci Sports Exerc 2005; 49:86-119.

[3.] Brust J.D., Roberts W.O., Leonard B.J. Girls' ice hockey injuries during tournament play: how do they compare in number, type and seriousness with boys' injuries? Med. J. Allina. 1998; 7 (1):27-9.

[4.] Brust JD, Leonard BJ, Pheley A et al. Children's ice hockey injuries. Am J Dis Child 1992; 146:741-7.

[5.] Cook DJ, Cusimano MD, Tator CH et al. Evaluation of the ThinkFirst Canada, Smart Hockey, brain and spinal cord injury prevention video. Injury Prevention 2003; 9:361-6.

[6.] Emery CA, Meeuwisse WH. Injury Rates, Risk Factors, and Mechanisms of Injury in Minor Hockey. The American Journal of Sports Medicine 2006; 34 (12):1960-9.

[7.] Goodman D, Gaetz M, Meichenbaum D. Concussions in hockey: There is cause for concern. Med Sci Sports Exerc 2001; 33:2004-9.

[8.] Groff P. Hockey Injuries. Ontario Injury Compass 2006; 3 (1).

[9.] Hagel BE, Marko J, Dryden D et al. Effect of body checking on injury rates among minor ice hockey players. CMAJ 2006; 175 (2):155-60.

[10.] Hockey Canada. Player Registration Table. 2008.

[11.] Hostetler SG, Xiang H, Smith GA. Characteristics of Ice Hockey-Related Injuries Treated in US Emergency Departments 2001-2002. Paediatrics 2004; 114 (6):661-6.

[12.] International Classifications of Disease V.10. 2007.

[13.] Macpherson AK, Rothman L, Howard A. Body-Checking Rules and Childhood Injuries in Ice Hockey. Pediatrics 2006; 117 (2):143-7.

[14.] Malina RM, Bouchard C. Growth, Maturation, and Physical Activity. Champaign, Illinois: Human Kinetics; 1991.

[15.] Marchie A, Cusimano MD. Bodychecking and concussions in ice hockey: Should our youth pay the price? CMAJ 2003; 169 (2):124-8.

[16.] McFaull S. Contact Injuries in Minor Hockey: A review of the CHIRPP Database from the 1998/1999 Hockey Season. 2001.

[17.] McKee P. Body Checking Motion Defeated by Hockey Canada 2007.

[18.] Population Counts, for Canada, Provinces and Territories, and Census Divisions by Urban and Rural, 2001 Census--100% Data 2001.

[19.] Regnier G, Boileau R, Marcotte G et al. Effects of Body-Checking in the Pee-Wee (12 and 13 Years Old) Division in the Province of Quebec. Castaldi C.R.; Horner E.F., editors. Philadelphia: ASTP STP 1050, American Society for Testing and Materials; 1989. 84-103 p. (Castaldi C.R.; Horner E.F. editors. Safety in Ice Hockey).

[20.] Schick DM, Meeuwisse W.H. Injury Rates and Profiles in Female Ice Hockey Players. Am J Sports Med 2003; 31 (1):47-52.

[21.] Sim FH, Chao EY. Injury potential in modern ice hockey. Am J Sports Med 1978; 6 (6):378-84.

[22.] Tegner Y, Lorentzon R, . Concussion among Swedish elite ice hockey players. Br J Sports Med 1996; 30:251-5.

[23.] Voaklander DC, Saunder DL, Quinney HA et al. Epidemiology of Recreational and Old-Timer Ice Hockey Injuries. Clin J Sport Med 1996; 60:15-21.

[24.] Willer B, Kroetsch B, Darling S et al. Injury Rates in House League, Select, and Representative Youth Ice Hockey. Med Sci Sports Exerc 2005; 37 (10):1658-63.

AUTHOR CORRESPONDENCE

Jonathan Michael Josse

York University

4700 Keele Street

Toronto, Ontario, Canada

M3J 1P3

Fax: [phone]

Phone: [phone] x.77216

[e-mail]

Jonathan M. Josse, MSc (1), Joseph R. Baker, PhD (1), and Alison K. Macpherson, PhD (1,2)

(1) School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada, and (2) Institute for Clinical Evaluative Sciences, Toronto, ON

Table 1: Hockey ICD-10-CA External Causes of Injury Codes
for Hockey Injury

ICD-10 CA Code   Injury Description

W21.02           Striking against or struck by hockey stick
W21.03           Striking against or struck by hockey puck
W22.02           Striking against or struck by/playing hockey
W51.02           Striking against or bumped into by another
                 person in hockey

Table 2: Frequency Distributions of Inpatient and Outpatient Hockey
Injuries in Ontario from 2004 -2006

Inpatient (DAD)                     Outpatient (NACRS)

Sex                     Count (%)   Sex                       Count (%)

Male                  870 (93.75)   Male                  48922 (90.86)
Female                  58 (6.25)   Female                  4921 (9.14)

Age Group               Count (%)   Age Group                 Count (%)

 5-14 years            239(25.75)   [less than or           2539 (4.71)
                                    equal to] 9 years
15-19 years           249 (26.83)  10-14 years            14454 (26.85)
20 years-24 years      78 (8.41)   15-19 years            15269 (28.36)
25 years-29 years      44 (4.74)   20 years-24 years        4953 (9.20)
30 years-34 years      73 (7.87)   25 years-29 years        3874 (7.19)
35 years-39 years      66 (7.11)   30 years-34 years        3523 (6.54)
40 years-44 years      83 (8.94)   35 years-39 years        3112 (5.78)
[greater than or
equal to] 45 years     96 (10.35)   40 years-44 years       2873 (5.34)
                                    45 years-49 years       1770 (3.29)
                                    50 years-54 years        743 (1.38)
                                    [greater than or         733 (1.36)
                                    equal to] 55 years/
                                    other
Total                   928 (100)   Total                   53843 (100)

Table 3: Mechanism of Hockey Injury within Inpatient and
Outpatient Databases from 2004 - 2006

Inpatient (DAD)

Mechanism of Injury                                 Count (%)

Striking against or struck by hockey stick          84 (9.05)
Striking against or struck by hockey puck           60 (6.47)
Striking against or struck by/playing hockey      401 (43.21)
Striking against or bumped into by another
person in hockey                                  383 (41.27)
Total                                               928 (100)

Outpatient (NACRS)

Mechanism of Injury                                 Count (%)

Striking against or struck by hockey stick      10719 (19.91)
Striking against or struck by hockey puck        9132 (16.96)
Striking against or struck by/playing hockey    17219 (31.98)
Striking against or bumped into by another
person in hockey                                15682 (29.13)
Missing                                           1091 (2.03)
Total                                             53843 (100)

Table 4: Frequency Distributions of Hockey Injuries by Body Region
between Outpatients and Inpatients from 2004 - 2006

                             Inpatient (DAD)   Outpatient (NACRS)
                                   Count (%)            Count (%)

Head/Face Injury                 124 (13.36)        18246 (33.89)
Neck Injury                        49 (5.28)          1645 (3.06)
Trunk/Pelvic Injury              114 (12.29)          3677 (6.83)
Shoulder/Upper Arm Injury          81 (8.73)         8579 (15.93)
Forearm/Wrist/Hand Injury        150 (16.16)        10692 (19.86)
Hip/Thigh Injury                   57 (6.14)           624 (1.16)
Knee/Leg/Ankle/Foot Injury       280 (30.17)         8100 (15.04)
Other Injuries                     73 (7.87)          2280 (4.23)
Total                              928 (100)          53843 (100)

Table 5: Mechanism of outpatient hockey injuries by demographic
variables and body part injured

                              Stick Impacts      Puck Impacts
                             (W21.02) n (%)     (W21.03 n (%)

Sex
Male                            9702 (19.8)       8377 (17.1)
Female                          1017 (20.7)        755 (15.3)

Age Group
[less than or equal to]         1166 (45.9)         234 (9.2)
 9 years
10-14 years                     2294 (15.9)        1370 (9.5)
15-19 years                     2371 (15.5)       1615 (10.6)
20 years-24 years               1318 (26.6)       1078 (21.8)
25 years-29 years               1011 (26.1)        959 (24.8)
30 years-34 years                882 (25.0)        966 (27.4)
35 years-39 years                643 (20.7)        895 (28.8)
40 years-44 years                511 (17.8)        926 (32.2)
45 years-49 years                334 (18.9)        573 (32.4)
50 years-54 years                106 (14.3)        252 (33.9)
[greater than or equal to]        83 (11.3)        264 (36.0)
55 years

Body Region
Head/Face                       6483 (35.5)       4359 (23.9)
Neck                             228 (13.9)         114 (6.9)
Trunk/Pelvic Injury              504 (13.7)         310 (8.4)
Shoulder/Upper Arm                220 (2.6)         181 (2.1)
Injury
Forearm/Wrist/Hand              2339 (21.9)       1617 (15.1)
Injury
Hip/Thigh Injury                   42 (6.7)          22 (3.5)
Knee/Leg/Ankle/Foot               581 (7.2)       2293 (28.3)
Injury
Other                            322 (14.1)        236 (10.4)

                                 Incidental
                                    Contact    Player Contact
                             (W22.02) n (%)    (W51.02) n (%)

Sex
Male                           15608 (31.9)      14344 (29.3)
Female                          1611 (32.7)       1338 (27.2)

Age Group
[less than or equal to]          639 (25.2)        443 (17.4)
 9 years
10-14 years                     5417 (37.5)       5068 (35.1)
15-19 years                     5263 (34.5)       5757 (37.7)
20 years-24 years               1316 (26.6)       1159 (23.4)
25 years-29 years               1033 (26.7)        808 (20.9)
30 years-34 years                928 (26.3)        681 (19.3)
35 years-39 years                900 (28.9)        583 (18.7)
40 years-44 years                825 (28.7)        547 (19.0)
45 years-49 years                481 (27.2)        348 (19.7)
50 years-54 years                221 (29.7)        137 (18.4)
[greater than or equal to]       196 (26.7)        151 (20.6)
 55 years

Body Region
Head/Face                       3486 (19.1)       3598 (19.7)
Neck                             512 (31.1)        729 (44.3)
Trunk/Pelvic Injury             1246 (33.9)       1532 (41.7)
Shoulder/Upper Arm              3793 (44.2)       4234 (49.4)
Injury
Forearm/Wrist/Hand              4007 (37.5)       2545 (23.8)
Injury
Hip/Thigh Injury                 256 (41.0)        292 (46.8)
Knee/Leg/Ankle/Foot             3065 (37.8)       2014 (24.9)
Injury
Other                            854 (37.5)        738 (32.4)

Table 6: Mechanism of inpatient hockey injuries by demographic
variables and body part injured

                                  Stick impacts     Puck Impacts
                                 (W21.02) n (%)   (W21.03) n (%)

Sex
Male                                   78 (9.0)         59 (6.8)
Female                                 6 (10.3)          * (1.7)

Age Group
5-14 years                             21 (8.8)          5 (2.1)
15-19 years                            20 (8.0)         11 (4.4)
20 years-24 years                      9 (11.5)        10 (12.8)
25 years-29 years                      8 (18.2)         5 (11.4)
30 years-34 years                     10 (13.7)          7 (9.6)
35 years-39 years                       * (6.1)          * (3.0)
40 years-44 years                      9 (10.8)          5 (6.0)
[greater than or equal to]              * (3.1)        15 (15.6)
 45 years

Body Region
Head/Face                             20 (16.1)        37 (29.8)
Neck                                  13 (26.5)          * (6.1)
Trunk/Pelvic Injury                   14 (12.3)          8 (7.0)
Shoulder/Upper Arm Injury               * (2.5)          * (1.2)
Forearm/Wrist/Hand Injury             18 (12.0)          * (1.3)
Hip/Thigh Injury                        * (1.8)          0 (0.0)
Knee/Leg/Ankle/Foot Injury             10 (3.6)          * (0.7)
Other                                   6 (8.2)          7 (9.6)

                             Incidental Contact   Player Contact
                                 (W22.02) n (%)   (W51.02) n (%)

Sex
Male                                 375 (43.1)       358 (41.1)
Female                                26 (44.8)        25 (43.1)

Age Group
5-14 years                           105 (43.9)       108 (45.2)
15-19 years                           99 (39.8)       119 (47.8)
20 years-24 years                     20 (25.6)        39 (50.0)
25 years-29 years                     21 (47.7)        10 (22.7)
30 years-34 years                     36 (49.3)        20 (27.4)
35 years-39 years                     31 (47.0)        29 (43.9)
40 years-44 years                     41 (49.4)        28 (33.7)
[greater than or equal to]            48 (50.0)        30 (31.3)
 45 years

Body Region
Head/Face                             28 (22.6)        39 (31.5)
Neck                                  19 (38.8)        14 (28.6)
Trunk/Pelvic Injury                   38 (33.3)        54 (47.4)
Shoulder/Upper Arm Injury             40 (49.4)        38 (46.9)
Forearm/Wrist/Hand Injury             61 (40.7)        69 (46.0)
Hip/Thigh Injury                      30 (52.6)        26 (45.6)
Knee/Leg/Ankle/Foot Injury           157 (65.1)       111 (39.6)
Other                                 28 (38.4)        32 (43.8)

* = cell size <5