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Do Mandatory Face Shields Reduce the Number of Craniomaxillofacial Injuries in the National Hockey League?

Do Mandatory Face Shields Reduce the Number of Craniomaxillofacial Injuries in the National Hockey League?



Do Mandatory Face Shields Reduce the Number of Craniomaxillofacial Injuries in the National Hockey League?




Journal of Oral and Maxillofacial Surgery, 2021-06-01, Volume 79, Issue 6, Pages 1313-1318, Copyright © 2021 American Association of Oral and Maxillofacial Surgeons


Purpose

The purpose of this study was to analyze the effectiveness of the National Hockey League's (NHL) mandatory visor policy on the number and type of craniomaxillofacial (CMF) injuries.

Materials and Methods

A cross-sectional study was designed using the 2 databases: the NHL Injury Viz and the Pro Sports Transactions. CMF injuries and player characteristics from the NHL's 2009-2010 through the 2016-2017 seasons were obtained. The study outcomes of games missed and number of injuries were compared before and after the implementation of the league rule.

Results

A total of 149 CMF injuries were included in the final sample. Following the mandatory visor rule, there were significant decreases in the total number of CMF injuries per season (14.3 vs 30.7, P = .01) and the number of upper face injuries per season (7.0 vs 16.7, P = .04). Although there was no difference in the ratio of upper facial injuries before and after the rule change, players who wore a face shield did have a lower proportion of upper face injuries among all CMF injuries sustained (42.9 vs 64.6%, P < .01). Ultimately, neither face shield use ( P = .49) nor implementing a mandatory face shield rule ( P = .62) changed the number of games missed when injury did occur.

Conclusions

Upper facial injuries were observed to be less common among players wearing face shields. After the NHL mandated face shields, there were significant decreases in the mean number of CMF and upper facial injuries per season. Face shields did not appear to influence the severity or downtime from injury that were sustained.

In the modern hockey era, players have access to better quality equipment and training. As a result, the sport is now more competitive and played at a faster pace than in the past. Of the 4 major sports leagues in North America, hockey had the highest prevalence of craniomaxillofacial (CMF) injuries compared with baseball, basketball, and football. Within hockey, the CMF region is known to be 1 of the most common locations of injury. Studies have shown that visor use decreases the occurrence of orbital and nonconcussive head injuries. Visors, or face shields, cover the top half of the face and are intended to protect the frontal bone, orbits, and malar eminences. Unfortunately, they are far from perfect as they leave the remainder of the lower and midface exposed ( Fig 1 ).

A hockey player is shown wearing the face shield, which is seen covering his zygoma, frontal bone, and orbits, while exposing the nose, mouth, and mandible.
Figure 1
A hockey player is shown wearing the face shield, which is seen covering his zygoma, frontal bone, and orbits, while exposing the nose, mouth, and mandible.

In the 2007-2008 NHL season, only 50% of players wore visors; this figure increased to 73% by 2013. The increase in voluntary use may be attributed to increased player awareness and carryover use from minor and junior leagues where visors have been mandatory. The NHL has been active in making efforts to reduce the number of player injuries, and, in response to growing concern, the league implemented a mandatory visor policy in 2013. The NHL rule change stated that current players who had played less than 25 games in the league at the time were required to wear a visor, along with any new players entering the league from then on out. As of 2017, 94% of active NHL players were wearing visors.

No studies have evaluated the results of the NHL rule change and whether the rule achieved its intended goal of reducing the number of facial injuries. The purpose of this study is to determine if the mandatory visor rule reduced the number and severity of CMF injuries. We hypothesized that the mean number of CMF injuries per season and the mean number of games missed due to injury would decrease after the 2013-2014 season.


Materials and Methods


Study Design

This was a cross-sectional study designed to determine the efficacy of the face shield rule. The NHL releases weekly injury reports of players, and both the NHL Injury Viz and Pro Sports Transactions databases collect and organize these injury press releases. These 2 databases were cross-referenced to obtain a comprehensive list of injuries after removing duplicate entries. Injuries documenting head and face injuries from regular season play were collected from the 2009-2010 season through the 2016-2017 season. The 2012-2013 season was excluded from this study because it was shortened due to contract disputes. Any CMF injury that was sustained at the same time as another injury was excluded from the study. Injuries not pertaining to the CMF region could cause the return-to-play timeline to be altered depending on the severity of these non-CMF injuries. The NHL has a very stringent concussion protocol, so it is possible that a player who otherwise would be able to return to play from his CMF injury remained sidelined because he cannot clear the concussion protocol.


Study Variables

Location sites were divided into either upper or lower face injuries. The upper face was defined as any site that would be reasonably protected by wearing the mandatory face shield. The upper areas included eyeball, orbit, zygoma, and periorbital soft tissues. The lower face was defined as any site below the malar eminences and included the nose, mouth, jaws, and perioral soft tissues. If the injury location was unclear or not specified in the injury report, replays were obtained and used to determine the primary location of impact.

The study predictors were the visor/face mask status of the injured player (present or absent) and the timing with the mandatory visor rule (before or after). The study outcomes were the mean number of CMF and upper face injuries per season and the mean number of games missed secondary to injury. The number of games missed served as a surrogate for injury severity and was collected from Pro Sports Transactions and subsequently confirmed on The Hockey Reference database by tracking games played by the team before the injured player returned.


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