Athletic Hip Injuries in Major League Baseball Pitchers Associated With Ulnar Collateral Ligament Tears

History of Ulnar Collateral Ligament Injury and College Pitcher Fastball Profiles: A Retrospective, Observational, Live Pitching Analysis

PURPOSE

The aim of this study was to retrospectively compare the fastball profiles of pitchers who had previously sustained grade I or II ulnar collateral ligament (UCL) injuries, were rehabilitated, and released back for competition with those of pitchers with no history of elbow injury.

METHODS

Eighteen pitchers from the pitching staff of 1 National Collegiate Athletic Association Division III team participated in this study. Group 1 had a history of grade I or II UCL injury (n = 8), and group 2 (n = 10) did not. A computerized pitch tracking device was used to analyze ball movement and pitching mechanics. The hypothesis was that the pitchers with a history of injury (group 1) would display differing fastball velocity-ball movement relationships compared to those without (group 2).

RESULTS

The groups had similar heights, weights, pitching experiences, and arm slot positions at ball release. The pitching coach-determined preinjury arm slot position and the postinjury computerized pitch tracking device measurements after return to competition displayed strong agreement (r = 0.83), suggesting comparable pre and postinjury pitching techniques. The groups had comparable glenohumeral joint range of motion and fastball profiles, except that group 1 released the ball at a 2.5 times lesser horizontal distance away from the pitching rubber center. Group 2 also displayed consistently more robust and more frequent fastball movement relationships with velocity, horizontal break, and vertical break than group 1.

CONCLUSIONS

Reduced horizontal ball release distances at comparable vertical ball release heights without changes in the arm slot position suggest that pitchers with a history of grade I or II UCL injury have greater contralateral trunk tilt and elbow flexion at ball release. Increased contralateral trunk tilt may occur to increase pitch velocity at the expense of ball movement while placing the pitching elbow in a potentially injurious position. Computerized fastball profile analysis using a computerized pitch tracking device, in conjunction with coach pitching technique observation, and team medical staff clinical examination may help better identify pitchers with an increased risk of UCL injury.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic II.

Current concepts: the hip, core and kinetic chain in the overhead athlete

BACKGROUND

As overhead sports continue to grow in popularity, there has been increased interest in optimizing sports performance and injury prevention in these athletes. The hip, core, and kinetic chain have become a focus of research in recent decades, and their importance in upper extremity mechanics is now being recognized.

METHODS

An extensive review was carried out to identify papers correlating the hip, core and/or kinetic chain in overhead athletic performance and injury.

RESULTS

Recent literature has shown that efficiency and synchrony of the hips and core during an overhead movement (such as in baseball, golf, tennis, or volleyball) is essential for a powerful and precise execution of the task. Impairments of the hip and core, particularly abnormal joint mobility or weakness, can limit efficient energy transfer through the kinetic chain and may negatively impact performance. Recent epidemiologic studies have found hip pain to be common in adolescent, collegiate, and adult athletes. Moreover, hip pain in overhead athletes specifically has also been found to occur at a high rate. Abnormalities in hip range of motion, hip morphology, and core strength can lead to abnormal mechanics upstream in the kinetic chain, which may place athletes at risk of injuries.

CONCLUSION

In this review, the complex and multifaceted relationship between the hip, core, and kinetic chain is highlighted with an emphasis on recent literature and relevant findings.

Initial kinematic chain injuries increase hazard of subsequent arm injuries in professional baseball pitchers

BACKGROUND

Currently, there are few studies that have evaluated the relationship between a lower extremity or trunk injury (kinematic chain) and subsequent arm injury. The purpose of this study was (1) to investigate the relationship between initial kinematic chain (lower extremity or trunk) injury and subsequent arm injury; and (2) to investigate the relationship between initial shoulder or elbow injury and subsequent arm injury.

METHODS

A 7-year prospective injury risk study was conducted with Minor League Baseball pitchers. Pitches, pitching appearances, athlete exposures (AEs), and arm injuries (≥1-day time loss) were documented throughout the season. Cox survival analyses with 95% confidence intervals (95% CIs) were performed. Confounders controlled for included age, body mass index, arm dominance, pitching role, previous arm injury, number of pitching appearances, and seasonal pitch load.

RESULTS

A total of 297 pitchers participated (total player days = 85,270). Arm injury incidence was 11.4 arm injuries/10,000 AEs, and kinematic chain incidence was 5.2 injuries/10,000 AEs. Pitchers who sustained a kinematic chain injury demonstrated a greater hazard (2.6 [95% CI: 1.2, 5.6], P = .019) of sustaining an arm injury. Pitchers who sustained an initial shoulder injury demonstrated a greater hazard (9.3 [95% CI: 1.1, 83], P = .047) of sustaining a subsequent shoulder or elbow injury compared with pitchers who sustained an initial elbow injury.

CONCLUSIONS

Pitchers who sustained an initial lower extremity or trunk injury demonstrated an increased subsequent arm injury hazard compared with pitchers who did not. Pitchers who sustained an initial shoulder injury demonstrated a greater hazard of sustaining a subsequent arm injury compared with pitchers who sustained an initial elbow injury. However, this secondary analysis should be interpreted with caution. Clinicians should monitor risk with workload accumulation, which may be related to pitching compensatory strategies in a fatigued state. Pitchers who sustain a shoulder injury should be evaluated and perform both shoulder and elbow rehabilitation strategies before return to sport.

Hip Abductor Strength Asymmetry: Relationship to Upper Extremity Injury in Professional Baseball Players

BACKGROUND

Hip strength is an important factor for control of the lumbo-pelvic-hip complex. Deficits in hip strength may affect throwing performance and contribute to upper extremity injuries.

HYPOTHESIS

Deficits in hip abduction isometric strength would be greater in those who sustained an upper extremity injury and hip strength would predict injury incidence.

STUDY DESIGN

Prospective cohort study.

LEVEL OF EVIDENCE

Level 3.

METHODS

Minor League baseball players (n = 188, age = 21.5 ± 2.2 years; n = 98 pitchers; n = 90 position players) volunteered. Hip abduction isometric strength was assessed bilaterally with a handheld dynamometer in side-lying position, expressed as torque using leg length (N·m). Hip abduction strength asymmetry was represented by [(trail leg/lead leg) × 100]. Overuse or nontraumatic throwing arm injuries were prospectively tracked. Poisson regression models were used to estimate relative risk ratios associated with hip asymmetry; confounders, including history of prior overuse injury in the past year, were included.

RESULTS

Hip abduction asymmetry ranged from 0.05% to 57.5%. During the first 2 months of the season, 18 players (n = 12 pitchers) sustained an upper extremity injury. In pitchers, for every 5% increase in hip abduction asymmetry, there was a 1.24 increased risk of sustaining a shoulder or elbow injury. No relationship between hip abduction strength and injury was observed for position players.

CONCLUSION

Hip abduction asymmetry in pitchers was related to subsequent upper extremity injuries. The observed risk ratio indicates that hip abduction asymmetry may contribute a significant but small increased risk of injury.

CLINICAL RELEVANCE

Hip abduction muscle deficits may affect pitching mechanics and increase arm stress. Addressing hip asymmetry deficits that exceed 5% may be beneficial in reducing upper extremity injury rates in pitchers.

Kinematic and kinetic analyses of professional pitchers with history of core or groin injuries: A propensity-score matched analysis

Background

Core injuries in professional baseball pitchers have been linked to both diminished performance and time missed during the season injury was sustained. It is currently unclear how a history of a core injury may affect the future pitching performance and mechanics of professional baseball pitchers.

Purpose

To compare kinetic and kinematic variables between professional baseball pitchers with prior core/groin injuries and those without prior injury.

Study design

Descriptive laboratory study.

Methods

Professional baseball pitchers with a history of core injury pitched 8-12 fastball pitches while evaluated with 3D-motion capture (480 Hz). Inclusion criteria necessitated that the core injury occurred within one to four-years prior to biomechanical evaluation and that the core injury required time off from professional play for a minimum of 2 weeks and maximum of 3 months. These pitchers were 4:1 propensity-scored matched by age, height, weight, and handedness to pitchers with no prior injury history (control). Twenty kinematic and eleven normalized and non-normalized kinetic parameters were compared between groups using appropriate parametric testing. Sub-analysis of pitchers with distinct core muscle and spinal injuries were also analyzed.

Results

The No Prior Injury (NPI) subgroup (n = 76) had significantly less elbow flexion at ball release (31 ± 5° vs. 35 ± 6° respectfully, p = 0.044) compared to the Core Musculature/Soft Tissue subgroup (CM/ST, n = 10), with no significant difference in kinematics for other injury groups (p > 0.05). The General Core/Groin injury group (GCG, n = 19) had significantly greater normalized elbow anterior force (43.9 ± 4.7 vs. 40.0 ± 5.2 %BodyWeight[BW], p = 0.006) and elbow flexion torque (4.3 ± 0.5 vs. 3.8 ± 0.5 %BWxBodyHeight[BH], p = 0.001) than the NPI pitchers. CM/ST had significantly greater normalized elbow anterior force (p = 0.031), elbow flexion torque (p = 0.002), and shoulder adduction torque (p = 0.007) than NPI pitchers.

Conclusion

Professional baseball pitchers with prior core/groin injuries demonstrated increased elbow anterior force and elbow flexion torque compared to pitchers with no prior core injuries. One possible explanation for this finding includes inadequate recruitment and utilization of the lower extremities as a component of the kinetic chain leading to compensation at the level of the throwing arm. Whether these kinetic differences arise as a consequence of injury or present a risk for such warrants additional investigation.

Lower extremity injuries in the baseball athlete

Baseball is unique in its multiple facets: pitching, hitting, base rounding, and fielding are distinct activities that require different athletic skills to perform at a high level. Likewise, these different aspects of the game can contribute to a multitude of varying injuries. While high-velocity overhead throwing, along with batting, can produce a plethora of upper extremity injuries that often garner attention, injuries to the lower extremity can severely impact a player’s performance and ability to compete. The rigors of the short, explosive sprinting required for base running, as well as the dynamic movement required for fielding, create ample opportunity for lower limb injury, and even subtle pathology can affect a pitcher’s ability to perform or increase their long-term risk of injury. Chronic injury from conditions such as femoroacetabular impingement and hip labral tears can also occur. The purpose of the present review is to summarize the relevant epidemiology, pathophysiology, and treatment of lower extremity injuries in baseball athletes, with reference to current research into the prevention and management of such injuries.

An Analysis of In Vivo Hip Kinematics in Elite Baseball Batters Using a Markerless Motion-Capture System

Purpose

The aim of this study was to investigate the kinematics of the asymptomatic baseball batter’s hips by comparing passive range of motion (PROM) and real-time active hip range of motion (AROM) and determine whether differences in ROM exist between lead and trail hips.

Methods

Parameters of passive hip ROM were obtained using a goniometer and physical examination standards. Active hip ROM during batting swings was captured with the Dynamic Athletic Research Institute’s markerless motion-capture system.

Results

Twenty-nine elite-level baseball players were recruited for participation. Comparison of lead and trail hips showed no significant differences in PROM. Statistically significant differences in AROM were found between lead and trail legs with large effect sizes for flexion (mean difference [MD°], 11.22), extension (MD°, 30.30), abduction (MD°, 6.24), adduction (MD°, 18.63), external rotation (MD°, 14.87) and total arc of rotation (MD°, 17.17) (P < .001 for all). External rotation in the lead hip approached maximum passive endpoint during early phases of the swing, whereas trail hip extension reached maximum passive endpoint during follow-through.

Conclusion

There is a significant difference in the AROM of the lead and trail hips during the batting swing, with active extension in the trail hip, active external rotation of the lead hip, and total arc of rotation of the lead hip nearing their respective passive endpoints and suggesting a potential for bony interaction in the hips of baseball batters.

Level of Evidence

Level 3, Cross-Sectional Study.

Evaluation of Athletes with Hip Pain

Hip pain is a common complaint in athletes and can result in a significant amount of time lost from sport. Diagnosis of the source of hip pain can be a clinical challenge because of the deep location of the hip and the extensive surrounding soft tissue envelope. Establishing whether the source of hip pain is intra-articular or extra-articular is the first step in the process. A thorough history and a consistent and comprehensive physical examination are the foundation for the proper management of athletes with hip pain.

Efficacy of Arm Care Programs for Injury Prevention

PURPOSE OF REVIEW

Arm care programs for baseball players are an increasingly popular area of interest for players, parents, coaches, sports performance staff, and team physicians. Once a general afterthought, the design of arm care programs is now heavily scrutinized in order to maximize performance and help reduce injury risk. Given the recent spike in interest for arm care programs for baseball players of all ages, the purpose of this work is to review the relevant literature regarding the efficacy of arm care programs and to discuss the authors' preferred, evidence-based principles for arm care programs.

RECENT FINDINGS

Arm care programs appear to provide favorable results for performance, maintenance of strength and flexibility, and reduced injury risk. These programs should be tailored to the demands of the athlete, which can change based on the time of year and physical demands of the player's position. A good program will incorporate flexibility, strengthening, proprioception, and joint mobility for the entire kinetic chain. Appropriate warm-up and cool-down periods are also important. Arm care programs should start with basic movement patterns before progressing to more advanced, coordinated exercises. Arm care programs are an important piece of a holistic approach to caring for the throwing arm of baseball athletes. In general, they appear to be a safe and efficacious way to help prevent a portion of throwing arm injuries. Further research is needed to determine the optimal arm care program for each athlete.

Ankle dorsiflexion deficit in the back leg is a risk factor for shoulder and elbow injuries in young baseball players

The relationship between ankle joint function and throwing-related injuries has not been demonstrated. We hypothesized that limited ankle joint range of motion (ROM) was related to risk factors for shoulder and elbow injuries in young baseball players. This 12-month prospective cohort study evaluated the age, height, weight, playing position, shoulder, elbow, and ankle function of 228 enrolled baseball players. Shoulder and elbow injuries were tracked during the season. Univariate and multivariate analyses were performed to identify risk factors for shoulder and elbow injuries among participants divided into non-injured and injured groups. Univariate analysis showed that age, height, weight, ROM of elbow flexion in the dominant arm, muscle strength ratio of shoulder abduction, and the likelihood of being a pitcher or a catcher were significantly greater in the injured group than in the non-injured group. ROM of shoulder abduction-external/internal rotation, shoulder total arc on the dominant arm, ankle joint dorsiflexion, and plantar flexion on the back (non-lead) and front (lead) legs were significantly less in the injured group than in the non-injured group. In conclusion, ROM dorsiflexion deficits in the back leg, shoulder abduction-external rotation in the dominant arm, ROM increase in elbow flexion on the dominant side, older age, and being a pitcher were significant independent risk factors for injury.

Lower Extremity Pain and Pitching Kinematics and Kinetics in Collegiate Softball Pitchers

The primary aims of the study were (1) to examine kinematics and kinetics of those pitching with and without lower extremity pain in collegiate softball pitchers, and (2) to determine if there was an association between the lower extremity pain and lower extremity kinematics, trunk kinematics, and shoulder kinetics in collegiate softball pitchers. Thirty-seven NCAA Division I female collegiate softball pitchers (19.8±1.3 yrs,173.7±7.7 cm, 79.0±12.4 kg) participated. Participants were divided into two groups, those who were currently experiencing lower extremity pain and those who were not. Participants threw three rise ball pitches. Kinematic data were collected at 100 Hz using an electromagnetic tracking system. Mann-Whitney U tests revealed no significant kinematic or kinetic differences between pitchers with and without lower extremity pain. Additionally, there were no significant correlations between pain and recorded kinematic and kinetic variables. Considering there were no biomechanical differences observed between pitchers, coaches and athletic trainers should take caution with athlete assessment since athletes may not display altered biomechanics. Further examination into the duration and degree of pain is needed in an attempt to fully understand the implication of pain and pitching mechanics.

Regional Interdependence and the Role of the Lower Body in Elbow Injury in Baseball Players: A Systematic Review

BACKGROUND

Elbow injuries are exceedingly common in baseball players. Previous studies have identified that upper extremity strength and range of motion deficits pose a risk for these injuries, but few studies have examined the effect of lower extremity deficits. Given the role of the lower extremity in the kinetic chain of the baseball throwing motion, lower body deficits may affect the kinematics of the upper extremity and play a role in the elbow injury of baseball players.

PURPOSE

To systematically review the current literature investigating the association of trunk and lower extremity deficits with elbow pain or injury in baseball players.

STUDY DESIGN

Systematic review.

METHODS

A systematic review of the literature was performed according to the PRISMA (Preferred Reporting Items for Systematic Meta-Analyses) guidelines to identify and analyze all previous studies focused on the association of elbow pain and/or injury with functional deficits of the trunk and lower extremities.

RESULTS

A total of 14 studies met inclusion criteria, examining a range of baseball players extending from youth to professional athletes. One of the 14 studies examined other types of overhead throwing athletes alongside baseball players. Lower extremity-related risk factors for elbow pain and injury in these athletes were found and stratified per level of play. Factors included specific hip range of motion, lower extremity injury or pain, balance, and foot arch posture. Associations were also found with lower extremity injury and noncompliance with primary prevention programs.

CONCLUSION

Specific lower extremity deficits were found to be independent risk factors for elbow pain and injury in throwing athletes at certain levels of play. Additionally, prevention programs designed to correct deficits in identified risk factors were effective in reducing the incidence of elbow injury in youth athletes. These results highlight the potential of screening and subsequent intervention to reduce the incidence of elbow injury in certain subsets of baseball players.

Adductor injuries in the National Basketball Association: an analysis of return to play and player performance from 2010 to 2019

Objectives: 1) To evaluate return to play (RTP) timing in National Basketball Association (NBA) athletes following adductor injuries, and 2) to evaluate the effect of adductor injuries on player performance, game availability, and career longevity following RTP. Methods: Adductor injuries in NBA athletes from the 2009-2010 to 2018-2019 seasons were identified utilizing publicly available records via previously validated methodology. RTP time was calculated, and player performance and game availability were compared pre- vs. post-injury. Additionally, an injury-free control group matched for age, BMI, position, and experience was assembled to allow for comparisons in performance, availability, and career length. Results: In total, 79 adductor injuries across 65 NBA athletes were identified. The average injured player was 28.3 ± 4.0 years of age, and had 6.5 ± 4.2 seasons of NBA experience. Guards were injured more frequently than forwards or centers (49% vs 25% vs 25%, respectively). All players were able to RTP following first-time adductor injury after missing an average of 7.7 ± 9.8 games (median [IQR]: 4 [1-9]) and 16.9 ± 20.4 days (median [IQR]: 9 [3.5-20]). Twelve players (18.5%) suffered an adductor re-injury at a mean latency of 509.5 ± 503.9 days. Adductor injuries did not result in significant changes in any major statistical category (points, assists, rebounds, steals, blocks, turnovers, field goal percentage), player efficiency rating (PER), minutes/game, games/season, or a number of all-star selections (all P > 0.05) following RTP. Additionally, when compared to matched controls, no difference was found in pre- to post-injury change of PER, games/season, or minutes/game (all P > 0.05). Career longevity was not significantly different between groups (P = 0.44). Conclusion: Following adductor injury, NBA players returned to gameplay after missing an average of 16 to 17 days, or 7 to 8 games. Adductor injury did not affect player performance, nor game availability or career longevity.

Step by Step Guide to Understanding the Kinetic Chain Concept in the Overhead Athlete

PURPOSE OF REVIEW

The purpose of this review will be to provide both a historical and recent review of the role of the kinetic chain for the overhead athlete. The kinetic chain concept will then be applied to clinical exercise modifications and integrations for prevention and treatment of shoulder injury.

RECENT FINDINGS

The primary conclusion reached through this review is the important role the lower extremity, trunk, and scapular region play in the development of optimal terminal segment acceleration in the overhead throwing and serving motion. Failure of any links in the kinetic chain has implications for shoulder and elbow injury in the overhead athlete. Modifications of traditional shoulder exercises emphasizing activation of the scapular stabilizers and core musculature alongside concomitant rotator cuff activation are recommended and supported in EMG research. Future research is needed to further identify risk factors and rehabilitation and prevention strategies and key clinical tests for the overhead athlete. The goal is to elucidate the important role the kinetic chain plays in both performance enhancement and injury prevention for the overhead athlete. Understanding the key role all segments of the kinetic chain play in the complex biomechanical segmental rotations required for high-level throwing and serving will assist clinicians who work with overhead athletes.