Patients With First-Time or Recurrent Patellar Dislocation Have a Similar High Rate and Extent of Articular Cartilage Injury Observed on Magnetic Resonance Imaging.

Purpose: To use magnetic resonance imaging (MRI) scans to compare the prevalence of articular cartilage damage in patients with a single patellar dislocation versus those with multiple dislocations and to compare the locations and severity of chondral injury between the groups. Methods: Patients with patellar dislocation between January 2017 and July 2021 were retrospectively identified. Patients with a documented history of patellar dislocation and an MRI scan of the affected knee were included. Patients with articular cartilage injury prior to the dislocation event were excluded. Articular cartilage injury was graded using a validated system: AMADEUS (Mean Total Area Measurement and Depth & Underlying Structures). Caton-Deschamps Index (CDI) scores and Dejour classifications of trochlear dysplasia were also collected. Data were calculated by performing t tests, Mann-Whitney tests, and χ2 or Fisher Exact tests to calculate P values for categorical data. Results: In total, 233 patients were included: 117 with primary dislocations and 116 with recurrent dislocations. Articular cartilage injuries were present in 51 patients with primary dislocations (43.6%) and 68 patients with recurrent dislocations (58.6%, P = .026). On comparison of the groups, the recurrent group contained a significantly larger proportion of female patients (65.5% vs 46.2%, P = .004). There was no difference in lesion size, subchondral bone defect, presence of bone edema, or total AMADEUS score between groups (P = .231). Caton-Deschamps Index scores were not significant when comparing between groups; however, the Dejour classifications showed higher grades in the recurrent group (P = .013 for A-D grading scale and P = .005 for high/low grading scale). Subgroup analysis revealed that when cartilage damage was present, patients from the primary group had significantly more full-thickness lesions (P < .001) and lower AMADEUS scores (P = .016). Conclusions: There was a similarly high prevalence of cartilage injury seen on MRI after both a primary patellar dislocation and a recurrent patellar dislocation. Chondral injury primarily affected the medial and lateral patellar facets and the lateral femoral condyle in both the primary and recurrent dislocation groups. However, the primary group showed an increased number of full-thickness lesions. There was no difference in lesion size, subchondral bone defect, presence of bone edema, or total AMADEUS score between the primary and recurrent groups. Level of Evidence: Level III, retrospective comparative prognostic investigation.

Kinematic and Kinetic Comparisons of Arm Slot Position Between High School and Professional Pitchers.

Background: Throwing arm kinetics differ in pitchers at varying arm slot (AS) positions (frontal-plane arm position at ball release relative to the vertical axis). Purpose: To determine how kinematic and kinetic values differ between professional and high school pitchers with varying AS positions, and whether these differences are similarly observed in both populations. Methods: High school (n = 130) and professional (n = 288) pitchers threw 8 to 12 fastballs under 3-dimensional motion capture technology. Pitchers in each cohort were subdivided based on mean AS position at ball release: AS1 (least degree of AS: most overhand throwing styles), AS2 (intermediate degree of AS: three-quarter throwing styles), or AS3 (greatest degree of AS: most sidearm throwing styles). Kinetic and kinematic parameters were compared between groups. Study Design: Controlled laboratory study. Results: High school pitchers had a more overhand AS at ball release (50° ± 11°) compared with professional pitchers (58° ± 14°) (P < .001). In both cohorts, AS1 pitchers had significantly greater shoulder abduction (high school, P <0.001; professional, P <0.0001) and lateral trunk flexion (high school, P < 0.001; professional, P <0.0001) at ball release compared with AS3 pitchers. Professional pitchers with an AS3 position had significantly delayed timing of maximum upper trunk angular velocity compared with AS1 pitchers (64% ± 7% vs 57% ± 7% of pitch time, respectively; P < .0001). A significant positive correlation between AS and elbow flexion torque was found in high school pitchers (P = .002; ß = 0.28), and a significant negative correlation between AS and elbow varus torque (P < .001; ß = -0.22) and shoulder internal rotation torque (P < .001; ß = -0.20) was noted in professional pitchers. Conclusion: AS position was related to shoulder abduction and trunk lateral tilt. Professional and high school pitchers with varying AS positions did not experience similar changes in throwing arm kinetics. Clinical Relevance: In professional pitchers, the earlier onset of maximum upper trunk angular velocity with overhand throwing style may reflect inappropriate pelvis-trunk timing separation, a parameter implicated in upper extremity injury, and the negative correlation between AS and elbow varus and shoulder internal rotation torque suggests that both excessive and minimal AS positions have negative implications.

In Vivo Effect of Partial Ulnar Collateral Ligament Tear Location on Ulnohumeral Joint Gapping With Stress Ultrasound in Baseball Pitchers.

BACKGROUND: Stress ultrasonography (SUS) has provided clinicians with an alternative means of evaluating ulnar collateral ligament (UCL) injury by dynamically assessing ulnohumeral joint space gapping under applied valgus stress. However, 3 previous cadaveric studies have evaluated the biomechanical effect of partial UCL tears at different anatomic locations with conflicting results. PURPOSE/HYPOTHESIS: The purpose of this study was to use in vivo data from patients with magnetic resonance (MR)-confirmed partial UCL tears to determine if anatomic partial tear location influenced the resultant stability of the elbow in terms of ulnohumeral joint gapping on SUS. It was hypothesized that no difference would be seen in the amount of ulnohumeral joint gapping based on MR-identified anatomic partial UCL tear location. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: All patients diagnosed with elbow injury from 2015 to 2020 were screened to identify competitive baseball pitchers with a partial UCL tear who received an SUS. Partial UCL tear was diagnosed via surgeon and radiologist interpretation of elbow MR imaging (MRI) as well as confirmation at the time of surgery as documented in the operative report. Demographic, injury, and treatment data were collected from the clinic notes, MRI reports, and stress ultrasound reports. Ulnohumeral joint gapping on SUS was calculated as the difference between ulnohumeral joint gapping without valgus stress versus ulnohumeral joint gapping with valgus stress (delta) as performed by a musculoskeletal radiologist. RESULTS: Overall, 60 male baseball pitchers (age, 19.2 ± 2.1 years), including 22 (37%) high school, 26 (43%) collegiate, and 12 (20%) professional pitchers, were evaluated. Regarding the location of partial UCL tears, 32 (53%) pitchers had proximal tears and 28 (47%) had distal tears. The mean delta value cohort was 2.1 ± 1.1 mm, and 34 pitchers (57%) had delta values >2.0 mm. Ulnohumeral joint gapping (high school [1.9 mm] vs collegiate [2.6 mm] vs professional [1.6 mm]; P = .004) and the percentage of pitchers with delta values >2.0 mm (45% vs 77% vs 33%; P = .017) differed based on level of competition. After controlling for age, body mass index, and level of competition in a multivariate linear regression, tear location was not related to ulnohumeral joint gapping (P = .499). CONCLUSION: No difference was observed in the amount of ulnohumeral joint gapping on SUS in symptomatic baseball pitchers with MR-identified partial UCL tears at differing anatomic locations. The findings of this study are contrary to previous cadaveric studies that have evaluated the effects of UCL tear characteristics on delta laxity.

Scapular Dyskinesis in the Athletic Patient: A Sport-Specific Review.

¼: Scapular dyskinesis is an alteration of normal scapular kinematics. It is essential that each patient be evaluated holistically and that sport-related factors be taken into account. ¼: The presentation of scapular dyskinesis may be highly variable depending on the underlying etiology or associated pathology, but the onset of symptoms is often gradual. ¼: Sport-specific literature on scapular dyskinesis is most commonly reported in the context of baseball, swimming, and tennis. Treatment is most often conservative and involves physical therapy directed at the scapular stabilizers.

Clinical Outcomes After Ulnar Collateral Ligament Reconstructions With Concomitant Ulnar Nerve Transposition in Overhead Athletes: A Matched Cohort Analysis.

BACKGROUND: Injury of the ulnar collateral ligament (UCL) has become increasingly common, particularly in overhead athletes. There is no consensus on management of the ulnar nerve in UCL reconstruction (UCLR) in patients with preoperative ulnar nerve symptoms, as literature supports both not decompressing the nerve as well as ulnar nerve transposition (UNT). HYPOTHESIS/PURPOSE: The purpose of this study was to compare subjective clinical outcomes and return-to-sports (RTS) metrics between patients who received UNT during UCLR and a matched cohort who underwent UCLR alone. We hypothesized that there would be no significant difference in patient outcomes or RTS metrics between the cohorts. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Using an institutional database, patients who underwent UCLR with UNT between 2007 and 2017 were retrospectively identified. These patients were matched based on sex, age at surgery (±3 years), and body mass index (±2 kg/m2) to a comparison group that underwent UCLR alone. Patients completed the Kerlan-Jobe Orthopaedic Clinic Shoulder & Elbow (KJOC) score, the Timmerman and Andrews elbow score, the Conway-Jobe scale, and custom patient satisfaction and RTS questionnaires. RESULTS: Thirty patients who underwent UCLR with concomitant UNT and 30 matched patients who underwent UCLR without UNT were available for follow-up at a mean of 6.9 (3.4-9.9) and 8.1 (3.4-13.9) years, respectively. The UNT group reported similar KJOC (78.4 in UNT vs 76.8; P = .780), Conway-Jobe (60% excellent in UNT vs 77% excellent; P = .504), Timmerman and Andrews (86.2 in UNT vs 88.8; P = .496), and satisfaction scores (85.3% in UNT vs 89.3%; P = .512) compared with UCLR group. In terms of RTS rate (84% in UNT vs 93% in UCLR; P = .289) and duration required to RTS (11.1 months in UNT vs 12.5 months in UCLR; P = .176), the 2 groups did not significantly differ. Finally, despite significant differences in preoperative ulnar nerve symptoms (100% in UNT vs 7% in UCLR; P < .001), the 2 groups did not statistically differ in the proportion of patients who experienced postoperative ulnar nerve symptoms (13% in UNT vs 0% in UCLR; P = .112). CONCLUSION: This matched cohort analysis showed no statistically significant differences in patient-reported outcomes and RTS between patients undergoing UCLR with and without UNT.

Increased Pitch Velocity Is Associated With Throwing Arm Kinetics, Injury Risk, and Ulnar Collateral Ligament Reconstruction in Adolescent, Collegiate, and Professional Baseball Pitchers: A Qualitative Systematic Review.

PURPOSE: To assess the relationship between pitch velocity and throwing arm kinetics, injury, and ulnar collateral ligament reconstruction (UCLr) among high school, collegiate, and professional baseball pitchers. METHODS: The Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, PubMed (2008-2019), and OVID/MEDLINE (2008-2019) were queried for articles that reported on pitch velocity predicting throwing arm kinetics, injury, or UCLr. The Methodological Index for Non-randomized Studies checklist was used to evaluate the quality of all included studies. Descriptive statistics with ranges were used to quantify data where appropriate. RESULTS: A total of 24 studies examining 2,896 pitchers, with Level of Evidence II-V were included. Intergroup analysis noted pitch velocity was significantly correlated with elbow varus torque in high school (R2 = 0.36), collegiate (R2 = 0.29), and professional (R2 = 0.076) pitchers. Elbow distraction force was positively associated with ball velocity in interpitcher analyses of high school (R2 = 0.373), professional (R2 = 0.175), and mixed-cohort evaluations (R2 = 0.624). Intragroup analysis demonstrated a strong association between pitch velocity and elbow varus torque (R2 = 0.922-0.957) and elbow distraction force (R2 = 0.910) in professional pitchers. Faster ball velocity was positively associated with a history of throwing arm injury (R2 = 0.194) in nonadult pitchers. In 2 studies evaluating professionals, injured pitchers had faster pitch velocity before injury compared with uninjured controls (P = .014; P = .0354). The need for UCLr was positively correlated with pitch velocity (R2 = 0.036) in professional pitchers. The consequences of UCLr noted little to no decrease in pitch velocity. CONCLUSIONS: Professional baseball pitchers with faster pitch velocity may be at the greatest risk of elbow injury and subsequent UCLr, potentially through the mechanism of increased distractive forces on the medial elbow complex. When a pitcher ultimately undergoes UCLr, decreases in pitching performance are unlikely, but may occur, which should encourage pitchers to caution against maximizing pitch velocity. LEVEL OF EVIDENCE: Level IV, systematic review of Level II-IV studies.

Increased Knee and Meniscal Injury Incidence in Professional Baseball Pitchers With Wider, Positive Stride Width.

BACKGROUND: Professional baseball pitchers sustain 75% of knee injuries while at the pitcher's mound, yet no pitching motion has been associated directly with such injuries. Stride width is a potential, modifiable risk factor worth investigating. HYPOTHESIS: Increased stride width in both the positive and negative directions (deviations from neutral stride width) would correlate with increased incidence of knee injury in pitchers. STUDY DESIGN: Descriptive laboratory. LEVEL OF EVIDENCE: Level 5. METHODS: Professional pitchers (n = 199) were evaluated with motion capture (480 Hz) while pitching. Injury history over 10 years was recorded at face-to-face interviews with pitchers. Players were subsequently grouped into stride width tertiles, compared for previous injury incidence of the lower extremities. Regressions were performed to observe performance benefits of stride width with ball velocity, accuracy, or consistency in pitch location as secondary outcomes. RESULTS: Of the 40 lower extremity injuries reported, meniscal injury (27.5%) was the most common, followed by foot stress fracture (20.0%). Significant differences in injury incidence were noted between the least and most positive stride width tertiles: lower extremity (10.4% vs 25.8%, respectively; P = 0.03), knee (3.0% vs 15.2%, respectively; P = 0.02), and meniscal (0.0% vs 12.1%; P = 0.00). Stride width of pitchers with meniscal injury in the lead (32.6 ± 7.1 cm, n = 5; P = 0.02) and stance leg (33.5 ± 10.6 cm, n = 5; P = 0.03) was significantly more positive than that of uninjured pitchers (21.1 ± 11.5 cm, n = 164). No significant relationships were established between stride width and ball velocity (P = 0.54) or pitch location metrics (P > 0.05). CONCLUSION: Pitchers with increased positive, stride width had significantly higher incidence of lower extremity injury (knee and meniscus). Wider, positive stride width may increase the degree of external rotation on the lead knee in a loaded state, which can place the medial side of the knee (and meniscus) at higher risk of injury. CLINICAL RELEVANCE: Decreasing stride width may be beneficial for professional pitchers to reduce the rate of lower extremity injury, while also preserving performance metric outcomes.

Evaluating Pelvis Rotation Style at Foot Contact: A Propensity Scored Biomechanical Analysis in High School and Professional Pitchers.

BACKGROUND: Early pelvis rotation has been associated with decreased throwing arm kinetics and conventionally was considered a component of proper pitching form in baseball throwers. However, previous assessments of pelvis rotation style have not accounted for confounders such as playing level, anthropometric characteristics, or ball velocity and have not evaluated sufficient sample sizes. PURPOSE: To compare kinetic and kinematic parameters based on pelvis rotation style in high school and professional pitchers. STUDY DESIGN: Descriptive laboratory study. METHODS: High school and professional baseball pitchers threw 8 to 12 fastball pitches while being evaluated using 3-dimensional motion capture (480 Hz). These pitchers were 1:1 propensity score matched by age, height, weight, handedness, and ball velocity based on early (<60°) versus late (≥60°) pelvis rotation style at foot contact. A total of 26 kinematic and 10 kinetic parameters were compared between groups. The kinematic parameters were used to conduct a linear regression between early and late pelvis rotation at foot contact. RESULTS: Pelvis rotation at foot contact was not significantly associated with ball velocity for either high school (P = .243) or professional pitchers (P = .075). No difference was found in elbow varus torque between high school early rotators (57.5 ± 14.9 N·m) and late rotators (51.3 ± 14.7 N·m; P = .036) and between professional early rotators (80.1 ± 11.8 N·m) and late rotators (79.0 ± 11.2 N·m; P = .663). At foot contact in high school pitchers, stride length increased by 2.1% of body height (B = -0.205; ß = -0.470; P < .001), trunk rotation increased by 4.2° (B = -0.417; ß = -0.488; P < .001), and trunk flexion at foot contact decreased by 4.4° (B = 0.442; ß = 0.476; P < .001) with every 10° increase in pelvis rotation. At foot contact in professional pitchers, stride length increased by 2.3% of body height (B = -0.229; ß = -0.478; P < .001), trunk rotation increased by 4.3° (B = -0.431; ß = -0.515; P < .001), and trunk flexion decreased by 4.0° (B = 0.404; ß = 0.373; P < .001) with every 10° increase in pelvis rotation. CONCLUSION: Pelvis rotation at foot contact was associated with several kinematic parameters in both groups and may influence mechanics further along the kinetic chain. Landing open or closed was not significantly associated with throwing arm kinetics or ball velocity for both high school and professional baseball pitchers, contrary to previous thought. CLINICAL RELEVANCE: Coaches and players may better focus their efforts on refining other kinematic parameters for enhanced performance outcomes and safe pitching mechanics.

The influence of excessive ipsilateral trunk tilt on upper-extremity throwing mechanics: a newly characterized parameter for biomechanical evaluation in high school and professional pitchers.

BACKGROUND: Although contralateral trunk tilt has been recognized, the phenomenon of excessive ipsilateral trunk tilt, often observed during earlier portions of the pitch, has not been explored as a potential correlate with throwing-arm kinetics among baseball pitchers. The purpose of this study was to evaluate kinetic and kinematic parameters among high school and professional pitchers related to excessive ipsilateral and contralateral trunk tilt. METHODS: Professional and high school pitchers were assessed with a 3-dimensional motion capture system (480 Hz) while pitching. Pitchers were grouped as follows: excessive ipsilateral tilt at foot contact (FC), neutral, or excessive contralateral tilt at ball release (BR). Trunk and shoulder kinematics as well as throwing-arm kinetics were compared between subgroups via post hoc regression analysis. RESULTS: Professional pitchers (n = 287) had significantly higher ipsilateral trunk tilt at FC (P < .001) than high school pitchers (n = 59). High school pitchers with excessive contralateral trunk tilt at BR experienced significantly higher shoulder superior force (27.0% ± 7.4% body weight [BW] vs. 17.6% ± 5.1% BW, P < .001) and shoulder anterior force (39.6% ± 8.2% BW vs. 35.7% ± 5.4% BW, P < .001) compared with the ipsilateral trunk tilt cohort but had comparable ball velocity (30.2 ± 3.2 m/s vs. 30.4 ± 2.1 m/s, P = .633). For professionals, for every 10° increase in ipsilateral trunk tilt at FC, ball velocity increased by 0.2 m/s (B = 0.02, ß = 0.07, standard error [SE] = 0.005, P = .010) whereas elbow varus torque decreased by 0.1% BW × height (B = -0.01, ß = -0.08, SE = 0.002, P < .001) and shoulder internal rotation torque decreased by 0.1% BW × height (B = -0.01, ß = -0.07, SE = 0.002, P = .005). CONCLUSION: High school and professional pitchers with excessive ipsilateral trunk tilt at FC consistently demonstrated significantly decreased throwing-arm kinetics (shoulder anterior force and shoulder superior force for high school pitchers and shoulder internal rotation torque and elbow varus torque for professional pitchers) compared with pitchers with excessive contralateral trunk tilt at BR, with equivalent ball velocity. In addition, professional pitchers appeared to engage in significantly greater ipsilateral trunk tilt during early portions of the pitch when compared with high school pitchers, which may represent a kinetically favorable method adopted by pitchers at higher playing levels to maintain adequate ball velocity while concomitantly minimizing throwing-arm kinetics.

Increased Elbow and Olecranon Injury History in Professional Pitchers With Increased Elbow Flexion at Ball Release.

BACKGROUND: Elbow flexion at late portions of the pitch has been associated with increased elbow varus torque, a kinetic surrogate associated with injury risk. Direct examinations of injury incidence with elbow flexion angles have not been conducted in professional pitchers. PURPOSE: To compare elbow and shoulder injury incidence among professional baseball players stratified by degree of elbow flexion at ball release (BR). STUDY DESIGN: Descriptive laboratory study. METHODS: Professional pitchers (N = 314) were instructed to pitch between 8 and 12 fastballs while being evaluated using motion capture technology. Upper extremity injury incidence was recorded upon interview. Pitchers were subsequently subdivided into 3 groups based on increasing elbow flexion at BR. Analysis of variance was used to compare participant characteristics and kinematic and peak kinetic variables. An odds ratio (OR) was calculated to determine the risk of having a previous upper extremity injury based on the degree of elbow flexion at BR. RESULTS: A total of 116 pitchers (132 documented injuries) had a previous upper extremity injury, with elbow injury (76 injuries; 57.6%) being the most common. Evaluation of kinetic values showed that pitchers with the smallest elbow flexion at BR had significantly less peak elbow flexion torque than did those with greatest elbow flexion at BR (3.8 ± 0.5 vs 4.1 ± 0.6 %weight × height; P = .003). Pitchers who demonstrated a greater than average degree of elbow flexion at BR when pitching were more likely to have a history of elbow injury (OR, 1.97; 95% CI, 1.14-3.40; P = .015) and olecranon spur formation or stress fracture (OR, 5.79; 95% CI, 1.25-26.85; P = .025). CONCLUSION: Pitchers with greater elbow flexion at BR had significantly higher odds of previous injury of the elbow and olecranon. Increasing elbow flexion has been shown to place the medial elbow in a position to carry a greater amount of load, which may be exacerbated during the final moments of the pitching motion. Professional pitchers can consider decreasing elbow flexion at BR as a potential, modifiable risk factor for elbow injury, in particular for olecranon spur formation and fracture. CLINICAL RELEVANCE: This study attempts to associate injury incidence with a modifiable, kinematic variable for an at-risk population.

Medial Elbow Instability Resulting From Partial Tears of the Ulnar Collateral Ligament: Stress Ultrasound in a Cadaveric Model.

BACKGROUND: There is consensus that most complete ulnar collateral ligament (UCL) injuries in throwers would benefit from surgical intervention. Optimal treatment for partial UCL tears remains controversial. Stress ultrasonography has become a well-accepted diagnostic modality for assessing UCL injury. HYPOTHESIS: Partial UCL tears will result in an intermediate increase in ulnohumeral joint space gapping as compared with that of an intact UCL and a complete UCL tear, but the degree of joint space gapping will vary by anatomic location of the partial tear. STUDY DESIGN: Controlled laboratory study. METHODS: Twenty-one cadaveric elbows were divided into 7 groups representing different anatomic locations of UCL partial tears. Partial tears were simulated by cutting 50% of the measured width of the UCL at 6 locations: distal anterior/posterior, midsubstance anterior/posterior, and proximal anterior/posterior. A seventh partial tear was created by partially elevating the undersurface of the distal UCL to simulate the radiographic "T-sign." Valgus stress (15 daN) was applied to each cadaveric elbow at 30° of flexion using a standardized device. Each specimen was tested intact, partially torn, and completely torn. At each state, joint space was measured using stress ultrasonography, and the difference in joint space from unstressed to stressed (delta) was recorded. RESULTS: There were 10 right and 11 left upper extremity specimens. The mean delta was 0.58 mm for the intact state and <0.75 mm in all groups. Both distal partial tear groups had mean deltas <0.75 mm, similar to intact elbows. Proximal tears and the T-sign demonstrated intermediate deltas (0.99-1.23 mm). Midsubstance partial tears demonstrated the largest deltas (1.57-2.03 mm), similar to those of the complete tears. All complete tear groups had a mean delta >1.5 mm (1.54-3.03 mm). CONCLUSION: These findings suggest that partial tears introduce a spectrum of instability from functionally intact to completely torn. As a result, some may be biomechanically amenable to nonoperative treatment, while others would be indicated for early reconstruction. Further research into the biological and biomechanical determinants of nonoperative treatment failure will assist with more precise treatment recommendations. CLINICAL RELEVANCE: Describing the biomechanical consequences of different, clinically significant partial UCL tears potentially allows more precise recommendations for operative and nonoperative treatment.

Ulnar Collateral Ligament Evaluation and Diagnostics.

The overhead throwing motion subjects the elbow to a predictable pattern of forces, including medial tension, lateral compression, and posterior shear, that in turn result in a predictable pattern of injuries. Careful history taking, thorough physical examination, and judicious diagnostic imaging allow clinicians to correctly diagnose ulnar collateral ligament (UCL) injury. Athletes with UCL injury complain of acute or chronic medial elbow injury, resulting in decreased throwing effectiveness, with loss of control and/or velocity. Magnetic resonance imaging is the gold standard for diagnosis, but stress ultrasound rapidly is becoming an important adjunct, particularly in diagnostically challenging situations.

Youth Single-Sport Specialization in Professional Baseball Players.

BACKGROUND: An increasing number of youth baseball athletes are specializing in playing baseball at younger ages. PURPOSE: The purpose of our study was to describe the age and prevalence of single-sport specialization in a cohort of current professional baseball athletes. In addition, we sought to understand the trends surrounding single-sport specialization in professional baseball players raised within and outside the United States (US). STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A survey was distributed to male professional baseball athletes via individual team athletic trainers. Athletes were asked if and at what age they had chosen to specialize in playing baseball at the exclusion of other sports, and data were then collected pertaining to this decision. We analyzed the rate and age of specialization, the reasons for specialization, and the athlete's perception of injuries related to specialization. RESULTS: A total of 1673 professional baseball athletes completed the survey, representing 26 of the 30 Major League Baseball (MLB) organizations. Less than half (44.5%) of professional athletes specialized in playing a single sport during their childhood/adolescence. Those who reported specializing in their youth did so at a mean age of 14.09 ± 2.79 years. MLB players who grew up outside the US specialized at a significantly earlier age than MLB players native to the US (12.30 ± 3.07 vs 14.89 ± 2.24 years, respectively; P < .001). Additionally, MLB players raised in the US recalled a significantly higher incidence of sustaining an injury attributed to specializing in baseball than MLB athletes raised outside the US (27.7% vs 20.6%, respectively; P = .05). CONCLUSION: This study challenges the current trends toward early youth sport specialization, finding that the majority of professional baseball athletes studied did not specialize as youth and that those who did specialize did so at a mean age of 14 years. With the potential cumulative effects of pitching and overhead throwing on an athlete's arm, the trend identified in this study toward earlier specialization within baseball is concerning.

Return to Play Criteria Following Surgical Stabilization for Traumatic Anterior Shoulder Instability: A Systematic Review.

PURPOSE: To identify and describe in the existing literature any criteria used for return to play following surgical stabilization for traumatic, anterior shoulder instability. METHODS: We performed a systematic review evaluating surgical stabilization for primary traumatic anterior shoulder instability in skeletally mature patients with a minimum of 1-year follow-up using Level I to IV studies in PubMed and EMBASE from January 1994 to January 2017. RESULTS: Fifty-eight studies with at least 1 explicitly stated criterion for return to play were identified from a review of more than 5,100 published articles. Seven different categories of return to play criteria were identified, the most common of which were time from surgery (89.6%), strength (18.9%), and range of motion (13.8%). Pain, stability, proprioception, and postoperative radiographic evaluation were also used. As hypothesized, in 75.8% of the included studies (44/58), time was the only criterion explicitly used. The most commonly used time for return to play was 6 months. CONCLUSIONS: This systematic review identifies 7 criteria that have been used in the available literature to determine when patients are ready to return to play; however, consistent with our hypothesis, 75% of studies used time from surgery as the sole listed criterion, with the most commonly used time point of 6 months postoperative. All of these criteria can be used in future research to develop a comprehensive checklist of functional criteria in hopes of reducing recurrent injury. LEVEL OF EVIDENCE: Level IV, systematic review.

Correlation of MRI to Arthroscopy in the Elbow: Thrower's Elbow and Ulnar Collateral Ligament Injury.

One cannot overstate the importance of a thorough history and physical examination, supplemented with directed imaging, to help pinpoint the exact cause of the athlete's elbow pain. Although plain radiographs should not be overlooked, advanced imaging plays a critical role in diagnosis and management of pathology in the thrower's elbow, including computed tomography, magnetic resonance imaging, and stress ultrasound. By judiciously combining these elements, the clinician can appropriately manage these injuries in order to successfully return the athlete to their preinjury level of play.

Early Single-Sport Specialization: A Survey of 3090 High School, Collegiate, and Professional Athletes.

BACKGROUND: Youth participation in organized sports in the United States is rising, with many athletes focusing on a single sport at an increasingly younger age. PURPOSE: To retrospectively compare single-sport specialization in current high school (HS), collegiate, and professional athletes with regard to the rate and age of specialization, the number of months per year of single-sport training, and the athlete's perception of injury related to specialization. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A survey was distributed to HS, collegiate, and professional athletes prior to their yearly preparticipation physical examination. Athletes were asked whether they had chosen to specialize in only 1 sport, and data were then collected pertaining to this decision. RESULTS: A total of 3090 athletes completed the survey (503 HS, 856 collegiate, and 1731 professional athletes). A significantly greater percentage of current collegiate athletes specialized to play a single sport during their childhood/adolescence (45.2% of HS athletes, 67.7% of collegiate athletes, and 46.0% of professional athletes; P < .001). The age of single-sport specialization differed between groups and occurred at a mean age of 12.7 ± 2.4 (HS), 14.8 ± 2.5 (collegiate), and 14.1 ± 2.8 years (professional) (P < .001). Current HS (39.9%) and collegiate athletes (42.1%) recalled a statistically greater incidence of sport-related injury than current professional athletes (25.4%) (P < .001). The majority (61.7%) of professional athletes indicated that they believed specialization helps the athlete play at a higher level, compared with 79.7% of HS and 80.6% of collegiate athletes (P < .001). Notably, only 22.3% of professional athletes said they would want their own child to specialize to play only 1 sport during childhood/adolescence. CONCLUSION: This study provides a foundation for understanding current trends in single-sport specialization in all athletic levels. Current HS athletes specialized, on average, 2 years earlier than current collegiate and professional athletes surveyed. These data challenge the notion that success at an elite level requires athletes to specialize in 1 sport at a very young age.

Elbow Injuries in Professional Baseball: Epidemiological Findings From the Major League Baseball Injury Surveillance System.

BACKGROUND: Elbow injuries cause significant disability for the throwing athlete. Scant data are available on the distribution and characteristics of these injuries in elite baseball players. No study exists that focuses solely on the epidemiological characteristics of elbow injuries in professional baseball players using a comprehensive injury surveillance system. HYPOTHESIS: Professional baseball players have a high occurrence of elbow injuries influenced by factors including length of time playing, time period within the annual baseball season, and specific position played. STUDY DESIGN: Descriptive epidemiological study. METHODS: Data on elbow injuries occurring during the 2011-2014 seasons were collected from Major League Baseball's Health Injury and Tracking System, a comprehensive injury surveillance system. Each specific type of elbow injury was evaluated with respect to overall injury rate, years as a professional player, mechanism of injury, treatment, average time lost, and return to play. RESULTS: During the study period, 3185 elbow injuries (n = 430 Major League; n = 2755 Minor League) occurred. The mean number of days missed and percentage requiring surgery were similar between Major and Minor League players. Overall, 20.0% (650/3185) of the injuries required surgical treatment. Pitchers were the most likely to incur an elbow injury (40.0% of injured athletes were pitchers), were the most likely to require surgery (34.2% of injured pitchers required surgery), and had the greatest mean number of days missed when treated nonsurgically (33.2 days). Medial injuries composed 42.1% (1342/3185) of all elbow injuries. Of all elbow surgeries performed during the study period, the highest percentage involved ligaments (372/650; 57.2%). CONCLUSION: Elbow injuries are a considerable source of disability in professional baseball players. Pitchers are most likely to incur these injuries, are most likely to require surgery, and have the highest mean number of days missed when treated nonsurgically. The most common injuries involve the medial elbow, with ligament injuries most often requiring surgery. This study represents the only investigation to date using a comprehensive injury surveillance system to examine elbow injuries in professional baseball players. It provides a basis for injury prevention and treatment recommendations, establishes the most thorough framework for determining elbow injury risk, and focuses continued research on elbow injury prevention in the elite baseball player.

Long-Term Outcomes in Anterior Cruciate Ligament Reconstruction: A Systematic Review of Patellar Tendon Versus Hamstring Autografts.

BACKGROUND: Much controversy still exists surrounding graft choice in anterior cruciate ligament (ACL) reconstruction. Over the past decade, an increase in comparative studies with longer follow-up has enhanced our understanding of current graft options and outcomes. PURPOSE: To describe the long-term comparative outcomes of ACL reconstruction with autograft bone-patellar tendon-bone (BPTB) versus autograft hamstring (HS) ACL reconstruction with regard to clinical and radiographic outcomes. STUDY DESIGN: Systematic review; Level of evidence, 2. METHODS: A search of the PubMed, MEDLINE, Cochrane, and Scopus databases was performed to identify studies in the English language with outcome data comparing ACL reconstruction utilizing autograft BPTB and autograft HS; only studies with a minimum 5-year follow-up were included. Outcome data included failure and complications, manual and instrumented laxity, patient-reported outcomes, and radiographic risk of osteoarthritis. RESULTS: Twelve studies with a total of 953 patients met the inclusion criteria. Of these studies, 8 were level 1 evidence and 2 were level 2. Mean follow-up was 8.96 years (range, 5-15.3 years). No differences in graft failure or manual or instrumented laxity were seen in any studies. Lower clinical outcomes scores and greater motion loss were seen in BPTB patients in 1 and 2 studies, respectively. Two of 4 studies reporting on anterior knee pain, and 3 of 7 that recorded kneeling pain found it more frequently among BPTB patients. One study found significantly increased reoperation rates in HS patients, while another found a similar result in BPTB, and 1 study reported a significant increase in contralateral ACL tears in BPTB patients. Three of 5 studies reporting on radiographic evidence of osteoarthritis noted significantly increased rates in BPTB patients. CONCLUSION: This systematic review comparing long-term outcomes after ACL reconstruction with either autograft BPTB or autograft HS suggests no significant differences in manual/instrumented laxity and graft failures between graft types. An increase in long-term anterior knee pain, kneeling pain, and higher rates of osteoarthritis were noted with BPTB graft use.

Anatomic Anterior Cruciate Ligament Reconstruction via Independent Tunnel Drilling: A Systematic Review of Randomized Controlled Trials Comparing Patellar Tendon and Hamstring Autografts.

PURPOSE: To collect the highest level of evidence comparing anatomic anterior cruciate ligament (ACL) reconstruction via independent tunnel drilling using bone-patellar tendon-bone (BTB) and hamstring tendon (HT) autografts in terms of clinical outcome and failure rate. METHODS: We performed a systematic review of clinical trials that randomized patients to ACL reconstruction with either BTB or HT autografts with a minimum 2-year follow-up. Only trials using independent tunnel drilling, including outside-in and anteromedial portal techniques, for both autografts were eligible for inclusion, whereas all transtibial studies were excluded. Study design, demographics, surgical technique, rehabilitation protocol, and clinical outcomes were compiled. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Quality assessment was performed using the Coleman Methodological Scale (CMS). RESULTS: Six published studies reporting on 5 randomized controlled trials (RCTs) met the inclusion criteria. No study reported a difference in rerupture rate between BTB and HT. BTB-reconstructed knees experienced a greater incidence of anterior knee pain or crepitus in 2/7 trials and radiographic evidence of degenerative change in 3/7 trials. HT-reconstructed knees had increased instrumented laxity in 2/7 trials and less knee flexion strength postoperatively. CONCLUSIONS: This study collects all available Level I and II evidence for anatomic ACL reconstruction using BTB and HT grafts. According to the data presented in these studies, clinical outcome scores and failure rates showed no differences for anatomic reconstruction using either autograft. However, in some studies, BTB-reconstructed knees experienced a greater incidence of anterior knee pain and radiographic evidence of degenerative change, and in others, HT-reconstructed knees had increased laxity and less knee flexion strength. In our opinion, both BTB and HT autografts remain valid options for ACL reconstruction when using anatomic drilling techniques, providing a stable knee with reliable return to activity. LEVEL OF EVIDENCE: Level II, systematic review of Level I and II studies.

Stress ultrasound evaluation of medial elbow instability in a cadaveric model.

BACKGROUND: An injury of the ulnar collateral ligament (UCL) is potentially career threatening for elite overhead-throwing athletes. Stress ultrasonography (SUS) allows for a rapid, cost-effective, and noninvasive evaluation of the UCL and elbow joint both at rest and with applied stress. PURPOSE/HYPOTHESIS: To determine the amount of cadaveric elbow valgus gapping with sequential sectioning of medial elbow structures as measured by SUS. It was hypothesized that the greatest increase in ulnohumeral joint gapping would be noted with release of the anterior bundle of the UCL. STUDY DESIGN: Descriptive laboratory study. METHODS: Twelve cadaveric elbows were divided into 2 groups and dissected in reverse sequences under the direct supervision of an experienced orthopaedic surgeon. Baseline ultrasound and SUS with applied valgus loads were performed by an experienced radiologist. A valgus load was applied at each sectioning interval using a standardized device. Ulnohumeral joint gapping in millimeters was measured by SUS for each step as the width of the medial joint from the trochlea to the sublime tubercle. The mean increases in joint gapping (Δ) between each step were calculated to quantify the additional gapping achieved with release of each sequential stabilizer. RESULTS: Release of the anterior band of the anterior bundle resulted in a mean Δ of 2.0 mm (95% CI, 1.1-2.8 mm). Release of the posterior band of the anterior bundle resulted in a mean Δ of 1.4 mm (95% CI, 0.6-2.2 mm). Release of the entire anterior bundle caused a mean increase in ulnohumeral valgus joint gapping of 3.4 mm (95% CI, 2.4-4.3 mm). Release of the remaining individual structures each resulted in a mean increase in valgus joint gapping of ≤0.8 mm. CONCLUSION: The results of the current cadaveric study suggest that different amounts of gapping are seen on SUS with sectioning of the medial elbow stabilizers. The hypothesis was confirmed with release of the anterior bundle of the UCL resulting in the greatest increase in joint gapping as measured by SUS. CLINICAL RELEVANCE: This study illustrates that SUS can identify the contributions of each anatomic portion of the UCL and the flexor-pronator mass to ulnohumeral joint stability in a cadaveric model.