Epidemiology of Shoulder and Elbow Injuries Among US High School Baseball Players, 2005-2006 Through 2014-2015

•  This study the most comprehensive investigation to date of shoulder and elbow injuries among high school baseball players. The overall injury rate was significantly higher for the shoulder (1.39 per 10,000 AEs) than the elbow (0.86 per 10,000 AEs), but only the rate of elbow injuries increased over the 9-year study duration. Both shoulder and elbow injury rates and patterns varied significantly by position, diagnosis, injury mechanisms, and setting (competition versus practice). A large number of these injuries resulted in more than 3 weeks’ time loss or in the player’s medical disqualification for the season, with a small, yet notable percentage of these injuries requiring surgery.

•  Limitations: •  Schools participating in this study were limited to those with National Athletic Trainers’ Association-affiliated certified ATs, meaning that our findings

may not be generalizable to all US high schools. •  Surgery was required for a minority of shoulder and elbow injuries (9.5% vs 5.3%, respectively), with surgery more often performed for position players

than pitchers (8.8% vs 7.4%, respectively). These numbers reflect only surgery performed during the academic year of the injury and reported by the AT. Thus, these numbers are likely an underestimation of the total number of athletes ultimately treated surgically for these injuries.

•  The database utilized in the study is not optimal for assessing surgical risk or assessing outcomes.

1.  2015-16 NFHS Handbook_2007-08 NFHS Handbook.qxd - 2014-15_Participation_Survey_Results.pdf. http://www.nfhs.org/ParticipationStatics/PDF/2014-15_Participation_Survey_Results.pdf. Accessed January 18, 2016.

2.  Merkel DL. Youth sport: positive and negative impact on young athletes. Open Access J Sports Med. 2013;4:151-160. 3.  Lyman S, Fleisig GS. Baseball injuries. Med Sport Sci. 2005;49:9-30. 4.  Olsen SJ, Fleisig GS, Dun S, Loftice J, Andrews JR. Risk factors for shoulder and elbow injuries in adolescent baseball pitchers. Am J Sports Med. 2006;34(6):905-912. 5.  Dick R, Sauers EL, Agel J, et al. Descriptive epidemiology of collegiate men’s baseball injuries: National Collegiate Athletic Association Injury Surveillance System, 1988-1989 through 2003-2004. J Athl Train.

2007;42(2):183-193. 6.  Lyman S, Fleisig GS, Waterbor JW, et al. Longitudinal study of elbow and shoulder pain in youth baseball pitchers. Med Sci Sports Exerc. 2001;33(11):1803-1810. 7.  Posner M, Cameron KL, Wolf JM, Belmont PJ, Owens BD. Epidemiology of Major League Baseball injuries. Am J Sports Med. 2011;39(8):1676-1680. 8.  US Census Bureau. Census regions of the United States. https://www.census.gov/const/regionmap.pdf. Accessed January 18, 2016.

Michael G. Saper, DO, ATC1; Lauren A. Pierpoint, MS2; Wie Liu, PhD3; R. Dawn Comstock, PhD2,4; John D. Polousky, MD5; James R. Andrews, MD1 1The Andrews Institute for Orthopaedics & Sports Medicine, Gulf Breeze, FL, U.S.A.; 2Department of Epidemiology, Colorado School of Public Health, University of Colorado Anschutz Medical Campus, Aurora, CO, U.S.A.; 3Department of Kinesiology, College of

Education, Auburn University, Auburn, AL, U.S.A.; 4Department of Pediatric Emergency Medicine, University of Colorado School of Medicine, Aurora, CO, U.S.A.; 5Children’s Health Andrews Institute for Orthopaedics & Sports Medicine, Plano, TX, U.S.A.

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• Overall Injury Patterns

•  The injury rate involving the shoulder was significantly higher compared with the elbow (RR, 1.61; 95% CI, 1.31-1.97). •  The rates of injury were higher in competitions compared with practices for both shoulders (RR, 1.44; 95% CI, 1.11–1.85) and elbows (RR, 2.15; 95% CI, 1.56–2.96). •  Pitchers sustained the majority of shoulder (39.6%) and elbow (56.9%) injuries and had a disproportionate proportion of chronic and overuse injuries.

Table1.OverallShoulderandElbowInjuryRates

Injuries,n Exposures,n

InjuryRate(per10,000AEs)

Shoulder 241 1,734,683 1.39Elbow 150 1,734,198 0.86

Table2:CharacteristicsofShoulderandElbowInjuriesCharacteristic Shoulder, Elbow

n (%) n (%) IPR (95% CI)Side of body Right 145 (71.4) 89 (67.9) 1.05 (0.81-1.37) Left 58 (28.6) 40 (30.5) 0.94 (0.63-1.40)New injury or recurrence New Injury 201 (83.8) 127 (84.7) 0.99 (0.79-1.24) Recurrence (this academic year) 19 (7.9) 13 (8.7) Recurrence (prior academic year) 18 (7.5) 9 (6.0) Other 2 (0.8) 1 (0.7)Position Pitcher 93 (39.6) 83 (56.9) 1.44 (1.07-1.93) Outfielder 57 (24.3) 11 (7.5) 3.22 (1.69-6.15) Infiedler 41 (17.4) 20 (13.7) 1.28 (0.75-2.18) Batter 9 (3.8) 20 (13.7) 3.53 (1.63-7.86) Catcher 19 (8.1) 10 (6.9) 1.18 (0.55-2.54) Base Runner 12 (5.1) 1 (0.7) N/A

Time loss Less than a week 94 (39.8) 49 (33.8) 1.18 (0.83-1.66) 1 - 3 weeks 81 (34.3) 53 (36.6) 0.94 (0.66-1.33) > 3 weeks 34 (14.4) 32 (22.1) 0.65 (0.40-1.06) Other 27 (11.4) 11 (7.6) 1.51 (0.75-3.04)Surgery, n (%) Yes 23 (9.5) 8 (5.3) 1.79 (0.80-4.01) No 218 (90.5) 142 (94.7) 0.96 (0.77-1.18)Basic injury mechanism No contact 82 (34.2) 60 (40.3) 0.85 (0.61-1.18) Overuse/chronic 89 (37.1) 50 (33.6) 1.10 (0.78-1.56) Contact with playing surface 37 (15.4) 7 (4.7) 3.28 (1.46-7.35) Contact with playing apparatus 12 (5.0) 23 (15.4) 0.32 (0.16-0.65) Contact with another person 14 (5.8) 2 (1.3) 4.46 (1.01-19.63)

Diagnosis Muscle strain 75 (31.3) 9 (6.1) 5.14 (2.57-10.26) Tendonitis 46 (19.2) 27 (18.2) 0.95 (0.59-1.53) Ligament sprain 13 (5.4) 49 (33.1) 6.11 (3.31-11.26) Contusion 13 (5.4) 23 (15.5) 2.87 (1.45-5.66)

•  Data Collection •  Ethics approval was obtained from our local institutional review board prior to initiation of

this study •  Shoulder and elbow data for US high school baseball players were obtained from the

National High School Sports-Related Injury Surveillance System, High School RIO (Reporting Information Online)

•  High schools with 1 or more National Athletic Trainers’ Association-affiliated certified athletic trainers (ATs) with a valid email address were invited to participate.

•  Responding high schools were categorized into 8 strata based on school population (enrollment ≤1000 or >1000) and US census geographic region.8

•  One hundred high schools from each of the 8 strata were randomly chosen to participate in the nationally representative sample.

•  Certified ATs from participating high schools reported injury and athlete-exposure (AE) information on the High School RIO website weekly throughout the academic year.

•  Injury and exposure data used in this study was collected from school years 2005-2006 through 2014-2015.

•  Definition of Injury and Exposure •  An AE was defined as 1 athlete participating in 1 school-sanctioned practice or

competition. •  A reportable injury was one that (1) occurred as a result of participation in an organized

practice or competition, (2) required medical attention by an AT or physician, and (3) resulted in a restriction of the athlete’s participation for ≥1 day after the day of injury.

•  Statistical Analyses •  Injury rates were calculated as the number of shoulder or elbow injuries per 10,000 AEs. •  Subgroup differences were evaluated with rate ratios (RRs) or injury proportion ratios

(IPRs) and 95% Confidence Intervals (CIs). For example, the RR calculation for comparing shoulder and elbow injury rates was follows:

•  RR = (total No. of competition shoulder injuries / total No. of competition baseball AEs) / (total No. of practice shoulder injuries / total No. of practice baseball AEs)

•  IPRs compared patterns of injuries. For example, the IPR calculation comparing the proportion of shoulder injuries to elbow injuries requiring surgery was:

•  IPR = (No. of shoulder surgeries / total No. of shoulder injuries) / (No. of elbow surgeries / total No. of elbow injuries)

•  Means and standard deviations were calculated for demographic variables (i.e., age). Statistical differences in demographics between groups were examined with independent t-tests. Comparison of categorical data (i.e., year in school) was performed using a Pearson’s χ2 test. Fisher’s exact test was used in cases of small sample sizes.

•  CIs not containing 1.00 and P values <.05 were considered statistically significant.

METHODS

RESULTS

Athletic participation is common among adolescents, with more than half of all high school students participating in school-sanctioned sports during the 2014-2015 academic year.1 Sport participation is beneficial to overall health, but carries risk of injury.2 With increasing student participation in high school athletics over the past decade1, shoulder and elbow injuries continue to be more prevalent. In addition, approximately one fourth of high school baseball players pitch,3 and the number of high school pitchers who require surgery for pitching-related injuries has increased.4 Previous epidemiologic studies have focused on injuries in little league, collegiate, and professional baseball players.5-7 An important area in need of further research is in shoulder and elbow injury prevention in high school baseball, and improving our knowledge of these common injuries is crucial to help drive targeted evidence-based prevention and treatment strategies. The purpose of this study was to provide a comprehensive understanding of the epidemiology of shoulder and elbow injuries among high school baseball players in the United States.

INTRODUCTION

DISCUSSION

REFERENCES

RESULTS Table3:CharacteristicsofShoulderandElbowInjuriesinPitchersandPositionPlayersCharacteristic Pitchers PositionPlayers

mean±SD,n(%) mean±SD,n(%)PValue/IPR(95%

CI)Age,years 16.3±1.3 16.3±1.2 0.92Height,inches 70.4±3.0 69.0±3.5 0.003Weight,lbs 170.8±2.4 164.1±1.9 0.03Sideofbody Right 120(77.4) 107(62.9) 1.23(0.95-1.60)Left 35(22.6) 61(35.9) 0.63(0.42-0.95)Yearinschool 0.69Freshman 29(16.9) 37(18.1) Sophomore 40(23.3) 45(22.1)Junior 47(27.3) 65(31.9)Senior 56(32.6) 57(27.9Playlevel 0.22Varsity 109(69.9) 109(63.0)JuniorVarsity 31(19.9) 51(29.5)Freshman 13(8.3) 11(6.4)TimelossLessthanaweek 49(29.2) 89(43.8) 0.67(0.47-0.94)1-3weeks 65(38.7) 67(33.0) 1.17(0.83-1.65)>3weeks 33(19.6) 31(15.8) 1.25(0.77-2.03)Other 10(12.5) 16(7.9) 1.59(0.83-3.04)SurgeryYes 13(7.4) 18(8.8) 1.19(0.58-2.42)BasicinjurymechanismNocontact 75(42.6) 62(30.4) 1.40(1.00-1.96)Overuse/chronic 85(48.3) 50(24.5) 1.97(1.39-2.79)Contactwithplayingsurface 3(1.7) 41(20.1) 11.82(3.66-38.18)Contactwithplayingapparatus 7(4.0) 28(13.7) 3.45(1.51-7.90)DiagnosisMusclestrain 42(24.0) 38(18.7) 1.28(0.83-1.99)Tendonitis 36(20.6) 35(17.2) 1.19(0.75-1.90)Ligamentsprain 38(21.7) 22(10.8) 2.00(1.18-3.39)Contusion 5(2.9) 31(15.3) 0.19(0.07-0.48)Tendonstrain 18(10.3) 16(7.9) 1.31(0.67-2.56)

•  Position players were more likely to sustain injuries by contact with the playing surface or apparatus.

•  For pitchers, muscle strains were most common injuries in the shoulder (38.7%) while ligament sprains were the most common injuries in the elbow (42.7%).

•  Increasing the level of play appears to increase the risk of shoulder and elbow injuries, with varsity athletes sustaining the highest proportion of injuries.

•  Injuries were more common in juniors and seniors with the lowest proportion of injuries occurring in freshman. However, the proportion of shoulder and elbow injuries was not statistically different between pitchers and position players.

•  The majority of pitchers with shoulder (70.8%) and elbow (64.6%) injuries returned to play within 21 days.

•  Elbow injuries sustained during pitching more frequently resulted medical disqualification (11.4% vs. 5.6%, respectively) compared with shoulder injuries.

•  Management was nonsurgical in the majority of pitchers with shoulder and elbow injuries (89.2% vs. 96.4%, respectively).