Abstract
Background:
Although lower extremity injuries are more common than upper extremity injuries in high school– and college-aged soccer players, upper extremity injuries may be equally severe. The epidemiology of upper extremity injuries is poorly characterized in this population.
Hypothesis:
Upper extremity injuries are an important contributor to soccer-related morbidity among high school– and college-aged players.
Study Design:
Descriptive epidemiology study.
Level of Evidence:
Level 3.
Methods:
The National Electronic Injury Surveillance System (NEISS) is a nationally representative sample of 100 hospital emergency departments (EDs). Each record contains demographic and injury information. Records from 1999 to 2016 were analyzed, including patients between the ages of 14 and 23 years with a soccer-related injury sustained at school or during an athletic event.
Results:
A total of 1,299,008 high school– or college-aged patients presented to the ED for a soccer-related injury from 1999 to 2016, of which 20.4% were in the upper extremity. Patients were predominantly male (58.0%) and high school–aged (81.4%). Males constituted a greater proportion of upper extremity injuries when compared with other injury locations (63.5% male for upper extremity). Upper extremity injuries were more likely to be fractures (43.7% vs 13.9%) and dislocations (7.1% vs 3.4%) and less likely to be strains/sprains (27.8% vs 56.6%). Males suffered more shoulder dislocations (81.8% males among patients with shoulder dislocation vs 57.8% among those with other injuries), finger dislocations (72.0% vs 58.0%), upper arm fractures (74.9% vs 57.6%), and forearm fractures (68.3% vs 57.3%).
Conclusion:
Upper extremity injuries are frequent in high school– and college-aged soccer players presenting to the ED. Efforts to reduce soccer-related injuries should include strategies targeting the upper extremity, perhaps reducing the incidence of high-energy falls.
Clinical Relevance:
Efforts to reduce soccer-related injuries should include strategies targeting upper extremity injuries, particularly among males and college-aged players.
Keywords: epidemiology, NEISS, soccer, upper extremity
Youth soccer participation in the United States has been increasing across all ages for the past 20 years.15,20 Lower extremity injuries are more common and better studied compared with upper extremity injuries in athletic populations. High school– and college-aged players, however, may frequently experience upper extremity injuries, including severe injuries such as dislocations and fractures.3,8,21
Data on the epidemiology, morbidity, and outcome of upper extremity injuries in soccer players are limited, potentially due to lack of academic interest. Upper extremity injuries, however, can have serious long-term consequences: Of soccer players 15 years or older with upper extremity fractures, 15% had not returned to play at 2 years, and 5% had persistent symptoms that impaired soccer ability.23 Of these, clavicle and distal radius fractures were the most severe, while finger fractures had shorter recovery times.23 Approximately half of high school soccer players who sustain a shoulder injury cannot return to sport for 3 or more weeks.3 Other studies of male soccer players undergoing shoulder surgery report recovery times of 3 to 4 months before returning to full participation.2,13 Among childhood soccer injuries treated in US emergency departments (EDs), 98.3% of patients were treated and released.1,26 In pediatric soccer players presenting to a level 1 trauma center, 25% had injuries severe enough to require trauma activation and hospitalization, while another study found that 60.6% of patients who required admission had a fracture.26,28 However, large-scale data describing the frequency and severity of upper extremity soccer injuries are limited.
Epidemiologic data are critical for those monitoring ongoing efforts to minimize injury via rule or equipment changes. The purpose of this study was to determine the epidemiology of upper extremity injuries in high school– and college-aged soccer players presenting to EDs in the United States. A secondary purpose was to comprehensively characterize upper extremity injury epidemiology with regard to annual trend, month, body part, sex, and age group.
Methods
Data Sources
As the National Electronic Injury Surveillance System (NEISS) is a publicly available and deidentified database, this study was not considered human subjects research under 45 CFR part 46 and was therefore exempt from institutional review board review. The NEISS database is maintained by the Consumer Product Safety Commission.5 The NEISS is a probability sample of 100 hospital EDs stratified based on hospital size, including weights that can be used to produce national estimates. Each record includes patient demographics, injury type (eg, body location, suspected injury diagnosis), and activities/products associated with the injury. Many orthopaedic investigations have used the NEISS to analyze injury epidemiology.1,16,19,26,27,29,31
Patient Selection
Records from 1999 through 2016 were analyzed for soccer-related injuries (code, 1267) occurring either at school or during sports among patients aged 14 to 23 years.
Dependent and Independent Variables
The primary outcome was injury occurrence. Independent variables included patient age, sex, diagnosis, and body part/region as well as month and year of injury. Patient age group was categorized as high school (14-18 years) or college (19-23 years). Injury diagnoses categorized as “other” included burns, amputations, crush injuries, foreign body injuries, electric shock, and dental injuries.
Statistical Analysis
Descriptive statistics across patient and injury characteristics were generated. Distribution of age group and sex for specific upper extremity injuries was determined, with proportions compared using chi-square or Fisher exact tests, as appropriate. Trends were assessed using logistic regression, with time as the independent variable and upper extremity injury versus injury in another location as the dependent variable. This approach allowed us to analyze trends in the proportion of upper extremity injuries over time. Records with missing data were excluded on a listwise basis. All analyses were completed using SAS software (version 9.4; SAS Institute). All analyses used statistical procedures that accounted for the NEISS survey design (eg, surveyfreq, surveymeans, surveylogistic). Statistical significance was set at P < 0.05 a priori.
Results
Demographics
In total, 1,299,008 high school and college patients (33,367 unweighted records) presented to the ED for a soccer-related injury from 1999 to 2016 (all future figures were calculated using weighted injury counts) (Table 1). Injuries followed a bimodal distribution, with peaks during the spring and fall, corresponding with soccer seasons. In particular, the September through October time period exhibited the largest numbers of both upper extremity and non–upper extremity injuries (33.9% of total injuries in September-October; n = 439,784).
Table 1.
Upper extremity injuries by sex and age groupa
| All Injuries | Non–Upper Extremity | Upper Extremity | |||
|---|---|---|---|---|---|
| Variable | n | % | % | % | P |
| Sex | <0.0001 | ||||
| Male | 753,669 | 58.0 | 56.6 | 63.5 | |
| Female | 545,171 | 42.0 | 43.4 | 36.5 | |
| Age group (y) | <0.0001 | ||||
| 14-18 | 1,057,752 | 81.4 | 80.9 | 83.4 | |
| 19-23 | 241,256 | 18.6 | 19.1 | 16.6 | |
Total patient numbers may differ slightly due to missing data for patient sex.
Injury Type and Pattern of Distribution
Upper extremity injuries were more likely to be fractures (P < 0.0001) and dislocations (P < 0.0001) and less likely to be strains/sprains (P < 0.0001) (Tables 2 and 3).
Table 2.
Injuries by body region and diagnosis (1999-2016)a
| Injury | Upper Extremity | Lower Extremity | Head and Neck | Trunk | Total |
|---|---|---|---|---|---|
| Concussion | |||||
| No. of discharges | 0 | 0 | 78,216 | 0 | 78,216 |
| Percentage of total | 0.0 | 0.0 | 6.0 | 0.0 | 6.0 |
| Column percentage | 0.0 | 0.0 | 25.5 | 0.0 | — |
| Row percentage | 0.0 | 0.0 | 100.0 | 0.0 | — |
| Contusion, abrasion, laceration | |||||
| No. of discharges | 43,789 | 118,355 | 110,643 | 36,928 | 309,715 |
| Percentage of total | 3.4 | 9.1 | 8.5 | 2.8 | 23.9 |
| Column percentage | 16.5 | 18.8 | 36.0 | 38.3 | — |
| Row percentage | 14.1 | 38.2 | 35.7 | 11.9 | — |
| Dislocation | |||||
| No. of discharges | 18,891 | 21,300 | 143 | 247 | 40,581 |
| Percentage of total | 1.5 | 1.6 | 0.0 | 0.0 | 3.1 |
| Column percentage | 7.1 | 3.4 | 0.0 | 0.3 | — |
| Row percentage | 46.6 | 52.5 | 0.4 | 0.6 | — |
| Fracture | |||||
| No. of discharges | 115,904 | 87,429 | 23,874 | 6336 | 233,543 |
| Percentage of total | 8.9 | 6.7 | 1.8 | 0.5 | 18.0 |
| Column percentage | 43.7 | 13.9 | 7.8 | 6.6 | — |
| Row percentage | 49.6 | 37.4 | 10.2 | 2.7 | — |
| Internal injury | |||||
| No. of discharges | 0 | 0 | 65,765 | 1820 | 67,585 |
| Percentage of total | 0.0 | 0.0 | 5.1 | 0.1 | 5.2 |
| Column percentage | 0.0 | 0.0 | 21.4 | 1.9 | — |
| Row percentage | 0.0 | 0.0 | 97.3 | 2.7 | — |
| Strain, sprain | |||||
| No. of discharges | 73,765 | 356,110 | 13,184 | 24,442 | 467,501 |
| Percentage of total | 5.7 | 27.5 | 1.0 | 1.9 | 36.0 |
| Column percentage | 27.8 | 56.6 | 4.3 | 25.4 | — |
| Row percentage | 15.8 | 76.2 | 2.8 | 5.2 | — |
| Otherb | |||||
| No. of discharges | 12,646 | 45,505 | 15,329 | 26,589 | 100,069 |
| Percentage of total | 1.0 | 3.5 | 1.2 | 2.0 | 7.7 |
| Column percentage | 4.8 | 7.2 | 5.0 | 27.6 | — |
| Row percentage | 12.6 | 45.5 | 15.3 | 26.6 | — |
| Total | |||||
| Number | 264,995 | 628,699 | 307,155 | 96,362 | 1,297,211 |
| Percentage | 20.4 | 48.5 | 23.7 | 7.4 | 100.0 |
Row and column sums may differ slightly from indicated totals due to rounding.
Injury diagnoses categorized as “other” included burns, amputations, crush injuries, foreign body injuries, electric shock, and dental injuries.
Table 3.
Upper extremity injuries by body part and diagnosis (1999-2016)
| Injury | Shoulder | Upper Arm | Elbow | Lower Arm | Hand or Wrist | Finger | Total |
|---|---|---|---|---|---|---|---|
| Contusion, abrasion, laceration | |||||||
| No. of discharges | 8676 | 446 | 6855 | 5436 | 17,090 | 5286 | 43,789 |
| Percentage of total | 3.3 | 0.2 | 2.6 | 2.1 | 6.4 | 2.0 | 16.5 |
| Column percentage | 14.2 | 20.2 | 38.4 | 18.0 | 16.4 | 10.6 | — |
| Row percentage | 19.8 | 1.0 | 15.7 | 12.4 | 39.0 | 12.1 | — |
| Dislocation | |||||||
| No. of discharges | 11,123 | 16 | 2150 | 6 | 182 | 5414 | 18,891 |
| Percentage of total | 4.2 | 0.0 | 0.8 | 0.0 | 0.1 | 2.0 | 7.1 |
| Column percentage | 18.2 | 0.7 | 12.0 | 0.0 | 0.2 | 10.9 | — |
| Row percentage | 58.9 | 0.1 | 11.4 | 0.0 | 1.0 | 28.7 | — |
| Fracture | |||||||
| No. of discharges | 23,960 | 1115 | 3649 | 21,876 | 43,303 | 22,001 | 115,904 |
| Percentage of total | 9.0 | 0.4 | 1.4 | 8.3 | 16.3 | 8.3 | 43.7 |
| Column percentage | 39.2 | 50.3 | 20.4 | 72.5 | 41.6 | 44.3 | — |
| Row percentage | 20.7 | 1.0 | 3.1 | 18.9 | 37.4 | 19.0 | — |
| Strain, sprain | |||||||
| No. of discharges | 14,669 | 257 | 4237 | 1648 | 37,981 | 14,972 | 73,765 |
| Percentage of total | 5.5 | 0.1 | 1.6 | 0.6 | 14.3 | 5.6 | 27.8 |
| Column percentage | 24.0 | 11.6 | 23.7 | 5.5 | 36.5 | 30.1 | — |
| Row percentage | 19.9 | 0.3 | 5.7 | 2.2 | 51.5 | 20.3 | — |
| Otherb | |||||||
| No. of discharges | 2682 | 380 | 963 | 1193 | 5428 | 1999 | 12,646 |
| Percentage of total | 1.0 | 0.1 | 0.4 | 0.5 | 2.0 | 0.8 | 4.8 |
| Column percentage | 4.4 | 17.2 | 5.4 | 4.0 | 5.2 | 4.0 | — |
| Row percentage | 21.2 | 3.0 | 7.6 | 9.4 | 42.9 | 15.8 | — |
| Total | |||||||
| Number | 61,110 | 2215 | 17,854 | 30,159 | 103,984 | 49,672 | 264,995 |
| Percentage | 23.1 | 0.8 | 6.7 | 11.4 | 39.2 | 18.7 | 100.0 |
Row and column sums may differ slightly from indicated totals due to rounding.
Injury diagnoses categorized as “other” included burns, amputations, crush injuries, foreign body injuries, electric shock, and dental injuries.
Injuries by Patient Sex
Males were disproportionately represented among patients presenting with shoulder dislocations (81.8% male among shoulder dislocations vs 57.8% male among all other injuries in the sample; P < 0.0001), finger dislocations (72.0% vs 58.0%; P = 0.0068), upper arm fractures (74.9% vs 57.6%; P < 0.0001), and lower arm fractures (68.3% vs 57.3%; P < 0.0001).
Injuries by Patient Age
College-aged patients were similarly disproportionately represented among those presenting with shoulder dislocation (51.0% college-aged among shoulder dislocation patients vs 18.3% college-aged among all other injuries in the sample; P < 0.0001) and finger dislocation (36.1% vs 18.5%; P < 0.0001) but constituted a significantly lower proportion of patients with lower arm fracture (14.1% vs 18.9%; P < 0.0001).
Discussion
Male patients were disproportionately represented among soccer players presenting to the ED for upper extremity injuries, as well as players with particularly severe upper extremity injuries (eg, dislocations and fractures). Patients with upper extremity injury were disproportionately high school–aged, though patients presenting specifically with dislocations of the upper and lower extremities were disproportionately college-aged.
While lower extremity injuries predominate among youth soccer players, upper extremity injuries contribute significantly to overall soccer-related morbidity.1,16,18,28 It is possible that upper extremity injuries in soccer tend to be of higher severity than lower extremity injuries given the greater kinetic energy associated with falls. The analysis of soccer data in the National Collegiate Athletic Association (NCAA) Injury Surveillance Program supports this hypothesis: Fractures were more likely to occur during a game than practice and more likely to affect the upper extremity, usually due to falling on an outstretched hand (hand, wrist, and finger injury) or landing on the shoulder (clavicle fracture).24
Higher rates of upper extremity injuries have been reported in male athletes, though the results are mixed.4,6,7,9,10,12,14,22,25 Darrow et al7 found higher rates of shoulder and hand/finger injuries in male high school soccer players presenting to athletic trainers. Males also accounted for the vast majority of elbow dislocations among high school athletes.9 The investigation by Hibberd et al14 of NCAA data also indicated higher rates of acromioclavicular joint sprain among male versus female soccer players. Yard et al,30 however, observed no difference in the proportion of upper extremity injuries among male versus female high school soccer players. With regard to our findings, it is possible that male and high school–aged soccer players experience a greater number of falls during sport, predisposing to a greater number of upper extremity injuries. Even if this hypothesis is correct, however, the cause of such falls remains unknown.
Dislocations and fractures were arguably the most severe upper extremity injuries prominent in our sample and disproportionately affected male players. Previous studies of soccer-related injury epidemiology have produced mixed results on sex-based differences in injury severity, though these studies have primarily examined lower extremity injuries.7,8,11,23,24,30 It is possible that particularly high–kinetic energy injuries occur more frequently among male youth soccer players, accounting for this relative disparity. Alternatively, it is possible that male youth soccer players disproportionately present to the ED for upper extremity injuries of higher severity.
Patients presenting with upper extremity dislocations were more likely to be college- than high school–aged. Krauetler et al17 similarly found that college athletes had a higher rate of shoulder dislocation injuries than high school athletes, with surgery being performed to correct 28% and 29.6% of shoulder dislocations in high school and college athletes, respectively. It is possible that college-aged athletes experience more dislocation injuries simply because of higher cumulative likelihood of past dislocation (ie, more years of exposure) and subsequent predisposition to future dislocations. If true, this hypothesis suggests that early intervention to reduce the rate of dislocation injuries at the high school or even pre–high school level may ultimately benefit players of all ages.
This investigation has several limitations. The NEISS collects generalized data regarding injuries and therefore lacks many variables that would be of interest in orthopaedic care (eg, specific mechanism of injury, fracture pattern, history of dislocation). Furthermore, the NEISS lacks information on long-term outcomes, including need for surgery, functional outcomes, and return to play. As with all retrospective data set analyses, these results are influenced by coding bias and unknown confounding variables. Because this sample consisted of only patients presenting to the ED, this probably represents inclusion bias as these patients likely have more severe injuries compared with the total population of injured soccer players.16 This limits the generalizability of these results to total soccer-related injuries, although is useful for looking at this subset of more severe injuries.
Conclusion
Soccer players presenting to the ED with upper extremity injuries were disproportionately male and high school–aged. Patients with upper extremity dislocations and fractures were disproportionately male, and those with dislocations were also disproportionately college-aged.
Footnotes
The following author declared potential conflicts of interest: Brett D. Owens, MD, is a paid consultant for Conmed, MTF, Mitek, Flexion Therapeutics, and Vericel and receives royalties from SLACK, Elsevier, and Springer.
References
- 1. Adams AL, Schiff MA. Childhood soccer injuries treated in U.S. emergency departments. Acad Emerg Med. 2006;13:571-574. [DOI] [PubMed] [Google Scholar]
- 2. Alentorn-Geli E, Alvarez-Diaz P, Doblas J, et al. Return to sports after arthroscopic capsulolabral repair using knotless suture anchors for anterior shoulder instability in soccer players: minimum 5-year follow-up study. Knee Surg Sports Traumatol Arthrosc. 2016;24:440-446. [DOI] [PubMed] [Google Scholar]
- 3. Bonza JE, Fields SK, Yard EE, Dawn Comstock R. Shoulder injuries among United States high school athletes during the 2005-2006 and 2006-2007 school years. J Athl Train. 2009;44:76-83. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4. Chandran A, Barron MJ, Westerman BJ, DiPietro L. Time trends in incidence and severity of injury among collegiate soccer players in the United States: NCAA Injury Surveillance System, 1990-1996 and 2004-2009. Am J Sports Med. 2016;44:3237-3242. [DOI] [PubMed] [Google Scholar]
- 5. Consumer Product Safety Commission. NEISS estimates query builder. Bethesda, MD: US Consumer Product Safety Commission; 2017. [Google Scholar]
- 6. Dalton SL, Kerr ZY, Dompier TP. Epidemiology of hamstring strains in 25 NCAA sports in the 2009-2010 to 2013-2014 academic years. Am J Sports Med. 2015;43:2671-2679. [DOI] [PubMed] [Google Scholar]
- 7. Darrow CJ, Collins CL, Yard EE, Comstock RD. Epidemiology of severe injuries among United States high school athletes. Am J Sports Med. 2009;37:1798-1805. [DOI] [PubMed] [Google Scholar]
- 8. Dick R, Putukian M, Agel J, Evans TA, Marshall SW. Descriptive epidemiology of collegiate women’s soccer injuries: National Collegiate Athletic Association Injury Surveillance System, 1988-1989 through 2002-2003. J Athl Train. 2007;42:278-285. [PMC free article] [PubMed] [Google Scholar]
- 9. Dizdarevic I, Low S, Currie DW, Comstock RD, Hammoud S, Atanda A., Jr. Epidemiology of elbow dislocations in high school athletes. Am J Sports Med. 2016;44:202-208. [DOI] [PubMed] [Google Scholar]
- 10. Eckard TG, Padua DA, Dompier TP, Dalton SL, Thorborg K, Kerr ZY. Epidemiology of hip flexor and hip adductor strains in National Collegiate Athletic Association athletes, 2009/2010-2014/2015. Am J Sports Med. 2017;45:2713-2722. [DOI] [PubMed] [Google Scholar]
- 11. Esquivel AO, Bruder A, Ratkowiak K, Lemos SE. Soccer-related injuries in children and adults aged 5 to 49 years in US emergency departments from 2000 to 2012. Sports Health. 2015;7:366-370. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12. Gornitzky AL, Lott A, Yellin JL, Fabricant PD, Lawrence JT, Ganley TJ. Sport-specific yearly risk and incidence of anterior cruciate ligament tears in high school athletes: a systematic review and meta-analysis. Am J Sports Med. 2016;44:2716-2723. [DOI] [PubMed] [Google Scholar]
- 13. Hart D, Funk L. Serious shoulder injuries in professional soccer: return to participation after surgery. Knee Surg Sports Traumatol Arthrosc. 2015;23:2123-2129. [DOI] [PubMed] [Google Scholar]
- 14. Hibberd EE, Kerr ZY, Roos KG, Djoko A, Dompier TP. Epidemiology of acromioclavicular joint sprains in 25 National Collegiate Athletic Association sports: 2009-2010 to 2014-2015 academic years. Am J Sports Med. 2016;44:2667-2674. [DOI] [PubMed] [Google Scholar]
- 15. Hootman JM, Dick R, Agel J. Epidemiology of collegiate injuries for 15 sports: summary and recommendations for injury prevention initiatives. J Athl Train. 2007;42:311-319. [PMC free article] [PubMed] [Google Scholar]
- 16. Kerr ZY, Pierpoint LA, Currie DW, Wasserman EB, Comstock RD. Epidemiologic comparisons of soccer-related injuries presenting to emergency departments and reported within high school and collegiate settings. Inj Epidemiol. 2017;4:19. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17. Kraeutler MJ, Currie DW, Kerr ZY, Roos KG, McCarty EC, Comstock RD. Epidemiology of shoulder dislocations in high school and collegiate athletics in the United States: 2004/2005 through 2013/2014. Sports Health. 2018;10:85-91. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18. Leininger RE, Knox CL, Comstock RD. Epidemiology of 1.6 million pediatric soccer-related injuries presenting to US emergency departments from 1990 to 2003. Am J Sports Med. 2007;35:288-293. [DOI] [PubMed] [Google Scholar]
- 19. Loder RT. The demographics of equestrian-related injuries in the United States: injury patterns, orthopedic specific injuries, and avenues for injury prevention. J Trauma Acute Care Surg. 2008;65:447-460. [DOI] [PubMed] [Google Scholar]
- 20. Longo UG, Loppini M, Berton A, Martinelli N, Maffulli N, Denaro V. Shoulder injuries in soccer players. Clin Cases Miner Bone Metab. 2012;9:138-141. [PMC free article] [PubMed] [Google Scholar]
- 21. Mariscalco MW, Saluan P. Upper extremity injuries in the adolescent athlete. Sports Med Arthrosc Rev. 2011;19:17-26. [DOI] [PubMed] [Google Scholar]
- 22. Mauntel TC, Wikstrom EA, Roos KG, Djoko A, Dompier TP, Kerr ZY. The epidemiology of high ankle sprains in National Collegiate Athletic Association sports. Am J Sports Med. 2017;45:2156-2163. [DOI] [PubMed] [Google Scholar]
- 23. Robertson GAJ, Wood AM, Bakker-Dyos J, Aitken SA, Keenan ACM, Court-Brown CM. The epidemiology, morbidity, and outcome of soccer-related fractures in a standard population. Am J Sports Med. 2012;40:1851-1857. [DOI] [PubMed] [Google Scholar]
- 24. Roos KG, Wasserman EB, Dalton SL, et al. Epidemiology of 3825 injuries sustained in six seasons of National Collegiate Athletic Association men’s and women’s soccer (2009/2010-2014/2015). Br J Sports Med. 2017;51:1029-1034. [DOI] [PubMed] [Google Scholar]
- 25. Rosene JM, Raksnis B, Silva B, et al. Comparison of concussion rates between NCAA Division I and Division III men’s and women’s ice hockey players. Am J Sports Med. 2017;45:2622-2629. [DOI] [PubMed] [Google Scholar]
- 26. Smith NA, Chounthirath T, Xiang H. Soccer-related injuries treated in emergency departments: 1990-2014. Pediatrics. 2016;138:e2016346. [DOI] [PubMed] [Google Scholar]
- 27. Van Tassel D, Owens B, Pointer L, Wolf JM. Incidence of clavicle fractures in sports: analysis of the NEISS database. Int J Sports Med. 2014;35:83-86. [DOI] [PubMed] [Google Scholar]
- 28. Walters BS, Wolf M, Hanson C, et al. Soccer injuries in children requiring trauma center admission. J Emerg Med. 2014;46:650-654. [DOI] [PubMed] [Google Scholar]
- 29. Waterman BR, Owens BD, Davey S, Zacchilli MA, Belmont PJ., Jr. The epidemiology of ankle sprains in the United States. J Bone Joint Surg Am. 2010;92:2279-2284. [DOI] [PubMed] [Google Scholar]
- 30. Yard EE, Schroeder MJ, Fields SK, Collins CL, Comstock RD. The epidemiology of United States high school soccer injuries, 2005-2007. Am J Sports Med. 2008;36:1930-1937. [DOI] [PubMed] [Google Scholar]
- 31. Zacchilli MA, Owens BD. Epidemiology of shoulder dislocations presenting to emergency departments in the United States. J Bone Joint Surg Am. 2010;92:542-549. [DOI] [PubMed] [Google Scholar]
