The Effect of Face Shields on Head and Neck Injuries in Ice Hockey
abstract & commentary
Synopsis: Full-length face shields significantly reduced the risk of facial and dental injuries without an increase in concussions or neck injuries.
Source: Benson BW, et al. Head and neck injuries among ice hockey players wearing full face shields vs half face shields. JAMA 1999;282(24): 2328-2332.
Ice hockey is known to be a fast and violent sport with frequent collisions between players and equipment resulting in injury. Many hockey associations across the United States and Canada have recently introduced rules requiring the use of face masks to help reduce facial injuries. At the same time, some have noted a trend of increased cervical spine injuries, leading to speculation that a full face shield may alter the spine biomechanics to increase injury risk. Another possibility is that style of play may be more aggressive with the full shield. This paper by Benson and colleagues from the University of Calgary in Alberta sought to determine whether full face shields alter the risk of head and neck injuries as compared to half face shields.
During the 1997-1998 season, 22 teams (642 players) were equally divided by use of full vs. half face shields based on rules unique to different Canadian intercollegiate divisions. After a preseason baseline examination players were prospectively followed during all practices and games, with all injuries recorded by the team trainer and/or physician. Reportable injuries were those involving facial, head, neck, or brachial plexus stretch (stinger-type) injuries or any injury resulting in at least one missed practice or game. A power analysis using injury data from the prior season was used to calculate sample size.
Practice and game participation information was 100% complete and injury information was obtained for 99.9% of cases involving missed time due to injury. Approximately 25,000 athlete exposures were accumulated for each group during the season. Although nearly equal numbers of athletes sustained injuries in each group (61% full shield and 63% half shield), there was a statistically significant difference in the types of injuries sustained. The number of players in the half shield group sustaining head and face injuries was nearly triple that in the full shield group (relative risk, 2.52). The risk of sustaining a dental fracture was 9.9 times greater and a facial laceration was 2.3 times greater for the half shield group. There was no difference in the rate of concussions between the two groups; however, the half shield group missed about twice as much time from practices and games due to concussions. Neck injuries were similar between groups, with five in the full shield group and seven in the half shield group.
Comment by David R. Diduch, MS, MD
This study by Benson et al seeks to dispel the myth that full face shields increase the risk of head and neck injuries. Using a prospective cohort design, Benson et al effectively demonstrated that there was no difference in the incidence of concussions or neck injuries between players wearing full or half face shields. The two groups were similar in every way except for face shield length, and data collection was nearly 100% complete using a validated system for injury surveillance. Sample size was also adequate and determined by a power analysis based on prior injury rates.
Thus, we can conclude that this study was well designed to determine the effect of face shield length on injuries in ice hockey. Differences in injury rates were striking, with two and a half times the number of head injuries and facial lacerations, and nearly 10 times the number of dental injuries (despite wearing mouth guards). Interestingly, time lost from participation due to concussion was greater for the half shield group, suggesting more severe injuries. Because players frequently are seen wearing the helmets more loosely and tipped back on the head to improve vision under the half shield, this may reduce the protective effect of the helmet.
This paper makes a strong argument for use of full face shields in ice hockey. The protective effect was significant, and no increased risk of injury was identified. One issue not addressed was player visibility and whether skills were compromised. If that is not a problem, it would be difficult for anyone to object to the use of full face shields.
Full face shields, as compared to half shields, were found in ice hockey to:
a. reduce dental injuries by nearly 10-fold.
b. reduce facial lacerations by 2.3-fold.
c. reduce head and facial injuries by 2.5-fold.
d. not affect the rate of neck injuries.
e. All of the above