Kyle T. Aune

Deficits in glenohumeral passive range of motion increase risk of elbow injury in professional baseball pitchers: a prospective study.

Background: Injuries to the elbow joint in baseball pitchers appear common. There appears to be a correlation between shoulder range of motion and elbow injuries. Purpose: To prospectively determine whether decreased ROM of the throwing shoulder is correlated with the onset of elbow injuries in professional baseball pitchers. Study Design: Cohort study; Level of evidence, 2. Methods: For 8 consecutive years (2005-2012), passive range of motion of both the throwing and nonthrowing shoulders of all major and minor league pitchers within a single professional baseball organization were measured by using a bubble goniometer during spring training. In total, 505 examinations were conducted on 296 pitchers. Glenohumeral external rotation and internal rotation were assessed in the supine position with the arm at 90° of abduction and in the plane of the scapula. The scapula was stabilized per methods previously established. Total rotation was defined as the sum of external rotation and internal rotation. Passive shoulder flexion was assessed with the subject supine and the scapula stabilized per methods previously established. Elbow injuries and days missed because of elbow injuries were assessed and recorded by the medical staff of the team. Throwing and nonthrowing shoulder measurements were compared by using Student t tests; 1-tailed Fisher exact tests were performed to identify significant associations between shoulder motion and elbow injury. Nominal logistic regression was performed to determine the odds of elbow injury. Results: Significant differences were noted during side-to-side comparisons within subjects. There were 49 elbow injuries and 8 surgeries in 38 players, accounting for a total of 2551 days missed. Neither glenohumeral internal rotation deficit nor external rotation insufficiency was correlated with elbow injuries. Pitchers with deficits of >5° in total rotation in their throwing shoulders had a 2.6 times greater risk for injury. Pitchers with deficit of ≥5° in flexion of the throwing shoulder had a 2.8 times greater risk for injury. Conclusion: Bilateral differences in shoulder total rotation and flexion had a significant effect on the risk for elbow injuries in pitchers. Clinicians need to be aware of these findings and plan preventive programs that address these issues in hopes of reducing elbow injuries.

Prevalence of Ulnar Collateral Ligament Surgery in Professional Baseball Players

Background: While the high rate of ulnar collateral ligament (UCL) injuries in professional baseball is widely discussed in the media and medical literature, the actual prevalence of UCL reconstruction has not been documented. Hypothesis: The prevalence of UCL reconstruction will be higher among pitchers than nonpitchers, and Major League Baseball (MLB) pitchers will have a higher prevalence than will minor league pitchers. Study Design: Descriptive epidemiology study. Methods: An online questionnaire was distributed to all 30 MLB organizations. Certified athletic trainers from each team administered the questionnaire to all players in the organization, including major league players and 6 levels of minor league players. Demographic data were compared between major and minor league players. Continuous variables (age, years of professional baseball, country of origin, etc) were compared with Student t tests (P < .05). Categorical variables (level, position, etc) were compared using chi-square analysis (P < .05). Results: A total of 5088 professional baseball players (722 major league and 4366 minor league) participated in the survey. Pitchers represented 53% of all players, and 497 players reported at least 1 UCL reconstruction, demonstrating a prevalence rate of 10% (497 of 5088). Pitchers reported a significantly higher prevalence of UCL reconstruction (16%; 437 of 2706) than nonpitchers (3%; 60 of 2382; P < .001). Among major league pitchers, 25% (96 of 382) had a history of UCL reconstruction, while minor league pitchers showed a 15% (341 of 2324) prevalence (P < .001). Major league pitchers were also significantly older (28.8 ± 3.9 years) than minor league pitchers (22.8 ± 3.0; P < .001). The majority of major leaguers (86%) had their UCL reconstruction as professional pitchers, whereas the majority of minor league pitchers (61%) underwent their UCL reconstruction during high school and college (P < .001). The rates of UCL revision, prior elbow surgery, prior shoulder surgery, and types of UCL graft were similar between the major league and minor league pitchers. No difference in prevalence was shown between pitchers born in the United States versus Latin American countries. Conclusion: Pitchers have a high prevalence of UCL reconstruction in professional baseball, with 25% of major league pitchers and 15% of minor league pitchers having a history of the surgery.

Deficits in Glenohumeral Passive Range of Motion Increase Risk of Shoulder Injury in Professional Baseball Pitchers: A Prospective Study

Background: Shoulder injuries from repetitive baseball pitching continue to be a serious, common problem. Purpose: To determine whether passive range of motion of the glenohumeral joint was predictive of shoulder injury or shoulder surgery in professional baseball pitchers. Study Design: Cohort study; Level of evidence, 2. Methods: Passive range of motion of the glenohumeral joint was assessed with a bubble goniometer during spring training for all major and minor league pitchers of a single professional baseball organization over a period of 8 successive seasons (2005-2012). Investigators performed a total of 505 examinations on 296 professional pitchers. Glenohumeral external and internal rotation was assessed with the pitcher supine and the arm abducted to 90° in the scapular plane with the scapula stabilized anteriorly at the coracoid process. Total rotation was defined as the sum of internal and external glenohumeral rotation. Passive shoulder flexion was measured with the pitcher supine and the lateral border of the scapula manually stabilized. After examination, shoulder injuries and injury durations were recorded by each pitcher’s respective baseball organization and reported to the league as an injury transaction as each player was placed on the disabled list. Results: Highly significant side-to-side differences were noted within subjects for each range of motion measurement. There were 75 shoulder injuries and 20 surgeries recorded among 51 pitchers, resulting in 5570 total days on the disabled list. Glenohumeral internal rotation deficit, total rotation deficit, and flexion deficit were not significantly related to shoulder injury or surgery. Pitchers with insufficient external rotation (<5° greater external rotation in the throwing shoulder) were 2.2 times more likely to be placed on the disabled list for a shoulder injury (P = .014; 95% CI, 1.2-4.1) and were 4.0 times more likely to require shoulder surgery (P = .009; 95% CI, 1.5-12.6). Conclusion: Insufficient shoulder external rotation on the throwing side increased the likelihood of shoulder injury and shoulder surgery. Sports medicine clinicians should be aware of these findings and develop a preventive plan that addresses this study’s findings to reduce pitchers’ risk of shoulder injury and surgery.

Biomechanical Performance of Baseball Pitchers With a History of Ulnar Collateral Ligament Reconstruction

Background: A relatively high number of active professional baseball pitchers have a history of ulnar collateral ligament reconstruction (UCLr) on their throwing elbow. Controversy exists in the literature about whether professional baseball pitchers regain optimal performance after return from UCLr. It has been suggested that pitchers may have different biomechanics after UCLr, but this has not been previously tested. Hypothesis: It was hypothesized that, compared with a control group without a history of UCLr, professional pitchers with a history of UCLr would have (1) significantly different throwing elbow and shoulder biomechanics; (2) a shortened stride, insufficient trunk forward tilt, and excessive shoulder horizontal adduction, characteristics associated with “holding back” or being tentative; (3) late shoulder rotation; and (4) improper shoulder abduction and trunk lateral tilt. Study Design: Controlled laboratory study. Methods: A total of 80 active minor league baseball pitchers (and their 8 Major League Baseball organizations) agreed to participate in this study. Participants included 40 pitchers with a history of UCLr and a matched control group of 40 pitchers with no history of elbow or shoulder surgery. Passive ranges of motion were measured for each pitcher’s elbows and shoulders, and then 23 reflective markers were attached to his body. The pitcher took as many warm-up pitches as desired and then threw 10 full-effort fastballs for data collection. Ball speed was recorded with a radar gun. The reflective markers were tracked with a 10-camera, 240-Hz automated motion analysis system. Eleven biomechanical parameters were computed for each pitch and then averaged for each participant. Demographic, range of motion, and biomechanical parameters were compared between the UCLr group and the control group by use of Student t tests (significance set at P < .05). Results: All hypotheses were rejected, as there were no differences in pitching biomechanics between the UCLr group and the control group. There were also no differences in passive range of motion between the 2 groups. Conclusion: Compared with a control group, active professional pitchers with a history of UCLr displayed no significant differences in shoulder and elbow passive range of motion and no significant differences in elbow and shoulder biomechanics. Clinical Relevance: Clinical studies have previously shown that 10% to 33% of professional pitchers do not return to their preinjury level; however, the current study showed that those pitchers who successfully return to professional baseball after UCLr pitch with biomechanics similar to that of noninjured professionals.

Return to Play After Partial Lateral Meniscectomy in National Football League Athletes

Background: Lateral meniscal injury is a common and possibly career-threatening injury among players in the National Football League (NFL). The rate of return to play (RTP) and factors that affect RTP after lateral meniscal injury in NFL players are currently not defined. Purpose: The aims of this study were to determine the rate of RTP to regular-season NFL game play of NFL players after arthroscopic partial lateral meniscectomy and to identify factors that can predict the ability to return to play. Study Design: Case series; Level of evidence, 4. Methods: Seventy-two patients undergoing 77 arthroscopic lateral partial meniscectomies were followed to determine the rate of RTP (defined as successful RTP in at least 1 regular-season NFL game after meniscectomy) and factors predicting players’ ability to return to play. Perioperative variables were recorded using retrospective chart review. Players’ heights and weights, dates of return, draft rounds, and counts of games, starts, and seasons both before and after meniscectomy were all collected from statistical databases maintained by the NFL. Chi-square and Student t tests were performed to assess differences among covariates with respect to an athlete’s ability to return to play, and odds ratios were calculated as appropriate. All percentages were calculated as percent of total procedures performed (n = 77). Results: Of the 77 partial lateral meniscectomies performed, 61% (n = 47) resulted in the athlete returning to play at his previous level of competition with an average length of time to RTP of 8.5 months; 19 (40%) of those who returned were still active in the NFL at the time of follow-up. Age at time of surgery, games and seasons played before surgery, and individual position were not significantly different between those who did and did not return to play. Undergoing a concomitant procedure did not affect an athlete’s ability to return to play, nor did concurrent arthroscopic anterior cruciate ligament reconstruction affect a player’s likelihood to return to play. Players drafted in the first 4 rounds of the NFL draft were 3.7 times more likely to return to play than players drafted after the fourth round, and players who started more than 46.2% of their games played (the mean value for this population) were 2.8 times more likely to return to play. Speed-position players (running backs, receivers, linebackers, and defensive backs) were 4.0 times less likely to return to play than non–speed position players (linemen and tight ends). Conclusion: The majority of NFL players undergoing arthroscopic lateral meniscectomy are able to return to play. Players selected earlier in the NFL draft and who are listed as starters in more of their games are more likely to return to play, as are linemen and tight ends. It is significantly more difficult for running backs, receivers, linebackers, and defensive backs to return to play.

Deficiencies in Pitching Biomechanics in Baseball Players With a History of Superior Labrum Anterior-Posterior Repair

Background: Baseball pitchers who undergo superior labrum anterior-posterior (SLAP) repair often have trouble returning to their previous level of performance. While the reason is often assumed to be diminished shoulder range of motion or other mechanical changes, differences in pitching biomechanics between baseball pitchers with a history of SLAP repair and pitchers with no injury history have not been studied previously. Hypothesis: The primary hypothesis was that compared with the control group, the SLAP group would exhibit compromised shoulder range of motion (external rotation and horizontal abduction) and internal rotation torque during pitching. Study Design: Controlled laboratory study. Methods: Pitching biomechanics were compared retrospectively between a group of 13 collegiate and professional pitchers with a history of a SLAP tear and a control group of 52 pitchers with no history of surgery; groups were matched by age, height, weight, and pitch velocity. Data were collected with an automated 3-dimensional motion analysis system while participants threw fastballs from the windup. Biomechanics of the shoulder (horizontal abduction and external rotation), elbow (flexion, extension velocity, and flexion torque), and body (stride length, shoulder horizontal adduction, and forward trunk tilt) were compared between the 2 groups. For each variable, a Student t test was used at an α level of .05. Results: Pitchers in the SLAP group exhibited significantly less shoulder horizontal abduction (10.0° ± 13.2° vs 21.0° ± 11.7°, respectively; P = .013) and shoulder external rotation (168.3° ± 12.7° vs 178.3° ± 7.3°, respectively; P = .016) than those in the control group. In addition, players in the SLAP group pitched with a more upright trunk, demonstrated by a less forward trunk tilt at the instant of ball release (30.2° ± 6.3° vs 34.4° ± 6.6°, respectively; P = .048). Conclusion: Pitchers with a history of SLAP repair produce less shoulder horizontal abduction, shoulder external rotation, and forward trunk tilt during pitching than do pitchers with no history of injury. Clinical Relevance: To facilitate normal pitching mechanics, shoulder external rotation and horizontal abduction at 90° should be primary objectives in surgical repair and rehabilitation after SLAP repair. In addition, pitchers should work with their pitching coaches to ensure proper forward trunk tilt.

Differences among fastball, curveball, and change-up pitching biomechanics across various levels of baseball.

Abstract Controversy continues whether curveballs are stressful for young baseball pitchers. Furthermore, it is unproven whether professional baseball pitchers have fewer kinematic differences between fastballs and off-speed pitches than lower level pitchers. Kinematic and kinetic data were measured for 111 healthy baseball pitchers (26 youth, 21 high school, 20 collegiate, 26 minor league, and 18 major league level) throwing fastballs, curveballs, and change-ups in an indoor biomechanics laboratory with a high-speed, automated digitising system. Differences between pitch types and between competition levels were analysed with repeated measures ANOVA. Shoulder and elbow kinetics were greater in fastballs than in change-ups, while curveball kinetics were not different from the other two types of pitches. Kinematic angles at the instant of ball release varied between pitch types, while kinematic angles at the instant of lead foot contact varied between competition levels. There were no significant interactions between pitch type and competition level, meaning that kinetic and kinematic differences between pitch types did not vary by competition level. Like previous investigations, this study did not support the theory that curveballs are relatively more stressful for young pitchers. Although pitchers desire consistent kinematics, there were differences between pitch types, independent of competition level.

Return to Play After Chondroplasty of the Knee in National Football League Athletes

Background: Knee injuries, including articular cartilage damage, are common in football players and are potentially career threatening. The rate of return to play (RTP) as well as the factors affecting return after arthroscopic chondroplasty of the knee is performed in National Football League (NFL) athletes are not known. Purpose: To determine the rate of return to regular season NFL competition after arthroscopic knee surgery including chondroplasty of articular cartilage lesions. In addition, identification of factors that influence successful return was investigated. Study Design: Case series; Level of evidence, 4. Methods: Athletes in the NFL who underwent arthroscopic chondroplasty at a single institution were identified. Retrospective chart review and review of the NFL online database were utilized to determine the rate of RTP and factors affecting an athlete’s ability to return. Chi-square and Student t tests were used to assess differences among players who were and were not able to RTP, and logistic regression was employed to determine a player’s odds of return. Results: There were 52 patients (54 procedures) identified from the surgical database who met the inclusion criteria for the study operated on between August 1, 2001, and March 31, 2011. Of these players, 36 (67%) were able to return to regular season NFL game play at an average of 8.2 months, including 13 (24%) who were still active in the NFL. The average time to follow-up was 5.9 years, and all players were allowed at least 2 years of follow-up. There was no significant correlation of RTP to athlete age, lesion size, lesion location, position played, or round selected in the NFL draft. Players who underwent concomitant microfracture were 4.4 times less likely to return to the NFL than were those who did not undergo this procedure (95% CI, 1.3-15.5). Athletes who played more than 11.6 games per season were 4.7 times more likely to RTP than were those who played fewer games per season (95% CI, 1.4-16.6). Athletes who returned to play competed in 56 fewer games, 3.3 fewer seasons, and played in 3.2 fewer games per season compared with their level of competition before surgery. Conclusion: A majority (67%) of NFL players are able to RTP after arthroscopic knee surgery including chondroplasty of articular cartilage lesions. Athletes who play more games per season are more likely to RTP after chondroplasty of articular cartilage lesions of the knee, but those undergoing concomitant microfracture are less likely to return. No statistical significance was determined when comparing the athletes who returned to play with respect to age at surgery, lesion location, lesion size, lesion grade, position that the athlete played, or draft round.

Injuries in an Extreme Conditioning Program

Background: Extreme conditioning programs (ECPs) are fitness training regimens relying on aerobic, plyometric, and resistance training exercises, often with high levels of intensity for a short duration of time. These programs have grown rapidly in popularity in recent years, but science describing the safety profile of these programs is lacking. Hypothesis: The rate of injury in the extreme conditioning program is greater than the injury rate of weightlifting and the majority of injuries occur to the shoulder and back. Study Design: Cross-sectional study. Level of Evidence: Level 4. Methods: This is a retrospective survey of injuries reported by athletes participating in an ECP. An injury survey was sent to 1100 members of Iron Tribe Fitness, a gym franchise with 5 locations across Birmingham, Alabama, that employs exercises consistent with an ECP in this study. An injury was defined as a physical condition resulting from ECP participation that caused the athlete to either seek medical treatment, take time off from exercising, or make modifications to his or her technique to continue. Results: A total of 247 athletes (22%) completed the survey. The majority (57%) of athletes were male (n = 139), and 94% of athletes were white (n = 227). The mean age of athletes was 38.9 years (±8.9 years). Athletes reported participation in the ECP for, on average, 3.6 hours per week (± 1.2 hours). Eighty-five athletes (34%) reported that they had sustained an injury while participating in the ECP. A total of 132 injuries were recorded, yielding an estimated incidence of 2.71 per 1000 hours. The shoulder or upper arm was the most commonly injured body site, accounting for 38 injuries (15% of athletes). Athletes with a previous shoulder injury were 8.1 times as likely to injure their shoulder in the ECP compared with athletes with healthy shoulders. The trunk, back, head, or neck (n = 29, 12%) and the leg or knee (n = 29, 12%) were the second most commonly injured sites. The injury incidence rate among athletes with <6 months of experience in the ECP was 2.5 times greater than that of more experienced athletes (≥6 months of experience). Of the 132 injuries, 23 (17%) required surgical intervention. Squat cleans, ring dips, overhead squats, and push presses were more likely to cause injury. Athletes reported that 35% of injuries were due to overexertion and 20% were due to improper technique. Conclusion: The estimated injury rate among athletes participating in this ECP was similar to the rate of injury in weightlifting and most other recreational activities. The shoulder or upper arm was the most commonly injured area, and previous shoulder injury predisposed to new shoulder injury. New athletes are at considerable risk of injury compared with more experienced athletes. Clinical Relevance: Extreme conditioning programs are growing in popularity, and there is disagreement between science and anecdotal reports from athletes, coaches, and physicians about their relative safety. This study estimates the incidence of injury in extreme conditioning programs, which appears to be similar to other weight-training programs.

Biomechanical Analysis of Weighted-Ball Exercises for Baseball Pitchers

Background: Weighted-ball throwing programs are commonly used in training baseball pitchers to increase ball velocity. The purpose of this study was to compare kinematics and kinetics among weighted-ball exercises with values from standard pitching (ie, pitching standard 5-oz baseballs from a mound). Hypothesis: Ball and arm velocities would be greater with lighter balls and joint kinetics would be greater with heavier balls. Study Design: Controlled laboratory study. Methods: Twenty-five high school and collegiate baseball pitchers experienced with weighted-ball throwing were tested with an automated motion capture system. Each participant performed 3 trials of 10 different exercises: pitching 4-, 5-, 6-, and 7-oz baseballs from a mound; flat-ground crow hop throws with 4-, 5-, 6-, and 7-oz baseballs; and flat-ground hold exercises with 14- and 32-oz balls. Twenty-six biomechanical parameters were computed for each trial. Data among the 10 exercises were compared with repeated measures analysis of variance and post hoc paired t tests against the standard pitching data. Results: Ball velocity increased as ball mass decreased. There were no differences in arm and trunk velocities between throwing a standard baseball and an underweight baseball (4 oz), while arm and trunk velocities steadily decreased as ball weight increased from 5 to 32 oz. Compared with values pitching from a mound, velocities of the pelvis, shoulder, and ball were increased for flat-ground throws. In general, as ball mass increased arm torques and forces decreased; the exception was elbow flexion torque, which was significantly greater for the flat-ground holds. There were significant differences in body positions when pitching on the mound, flat-ground throws, and holds. Conclusions: While ball velocity was greatest throwing underweight baseballs, results from the study did not support the rest of the hypothesis. Kinematics and kinetics were similar between underweight and standard baseballs, while overweight balls correlated with decreased arm forces, torques, and velocities. Increased ball velocity and joint velocities were produced with crow hop throws, likely because of running forward while throwing. Clinical Relevance: As pitching slightly underweight and overweight baseballs produces variations in kinematics without increased arm kinetics, these exercises seem reasonable for training pitchers. As flat-ground throwing produces increased shoulder internal rotation velocity and elbow varus torque, these exercises may be beneficial but may also be stressful and risky. Flat-ground holds with heavy balls should not be viewed as enhancing pitching biomechanics, but rather as hybrid exercises between throwing and resistance training.