DENVER – High school girl athletes are at 3.3-fold greater risk of incurring an anterior cruciate ligament injury than are boys playing the same or similar sports, according to a national study.
Of the nine sports assessed in the study, the highest ACL injury rate occurred in girls’ soccer, with 13.0 cases per 100,000 athletic exposures. In contrast, the rate in boys’ soccer was 4.8 cases per 100,000 athletic exposures, with an athletic exposure defined as one practice or game, Natalie McIlvain explained at the annual meeting of the American Public Health Association.
In girls’ basketball, the ACL injury rate was 9.1/100,000 athletic exposures. Yet in boys’ basketball, a sport with similar rules and equipment but bigger, heavier participants, the rate was just 2.2/100,000, said Ms. McIlvain of the Center for Injury Research and Policy at Nationwide Children’s Hospital in Columbus, Ohio.
Each year more than 7 million high school students participate in interscholastic sports. ACL injuries are the costliest type of sports injury occurring in these young athletes, as they often require expensive surgery and lengthy physical rehabilitation.
In order to better understand the epidemiology of high school ACL injuries, Ms. McIlvain and her coinvestigators analyzed data from the Centers for Disease Control and Prevention–sponsored National High School Sports-Related Injury Surveillance Study. In this study, certified athletic trainers at 100 nationally representative high schools used an online data-collection system to record the details of all athletic injuries, large or small, occurring during the 2007-2008 through 2009-2010 academic years. During the study period, the trainers documented 397 ACL injuries, extrapolating to an estimated 128,374 ACL injuries occurring nationally each year among high school athletes.
ACL injuries accounted for 3.1% of all sports injuries and 21% of all knee injuries. Seventy-seven percent of the ACL injuries required surgery. Nearly 50% of athletes with an ACL injury were medically disqualified for the season. Another 26% returned to play after 3 weeks or longer.
The overall incidence of ACL injury was 6.7/100,000 exposures. The rate was 18.0/100,000 exposures in competition, more than seven times the incidence of 2.5/100,000 during practices.
Forty-five percent of ACL injuries resulted from player-player contact. "That’s interesting, especially given that seven of the nine sports we studied were noncontact sports," Ms. McIlvain observed.
A striking gender-related difference in mechanism of injury was noted only in soccer. Forty-three percent of ACL injuries in girls’ soccer players involved player-player contact, and 11% were due to player-surface contact; in contrast, only 28% of ACL injuries in boys’ soccer involved player-player contact, while fully 42% resulted from player-surface contact. The explanation for this difference is unknown.
ACL injuries occurred in girls’ softball at a rate of 2.7/100,000 athletic exposures, compared with 0.7/100,000 exposures in boys’ baseball. For boys, football had by far the highest rate of ACL injuries: 11.1/100,000 athletic exposures. Wrestling had a 4.8/100,000 rate. ACL injuries occurred in girls’ volleyball at a rate of 3.1/100,000 athletic exposures.
The data used were from a study sponsored by the Centers for Disease Control and Prevention. Ms. McIlvain declared having no relevant financial relationships.