Unaccounted for Pitch Volume Among Adolescent Baseball Pitchers During a Travel Baseball Season.

OBJECTIVE: The primary aim was to compare differences in live game pitch counts (LGPCs) with all pitch counts (APCs) over the course of a youth baseball season. DESIGN: Prospective longitudinal study. SETTING: Midwest youth travel baseball. PARTICIPANTS: Ten male baseball players part of a youth baseball travel team. VARIABLES: Demographic data, pitch counts (practice, game, warm-up, and bullpen), innings pitched, and recommended rest days. MAIN OUTCOME MEASURES: Live pitch counts compared with APCs and the relationship to recommended rest days. RESULTS: During the season, 7866 pitches were recorded among 9 pitchers. By using the LGPC method alone, 42.5% of the pitches were unaccounted for. When considering age-specific rest days suggested by Pitch Smart Guidelines (PSGs), there were 104 rest days unaccounted for by using the live game pitch method. CONCLUSION: There is a high number of unaccounted for pitches and an underestimation of rest days per outing when using live game methods. Revisions to the PSGs that include all pitches should be considered to accurately reflect pitching volume, which may be associated with the rising rate of injuries among these athletes.

The effect of safety modifications on head kinematics experienced during common skills in women's artistic gymnastics.

The objective of this study was to evaluate the effect of skill modifications on head motion experienced during women's artistic gymnastics skills. Nine gymnasts (four beginner and five advanced) completed three trials of up to 24 skill progressions, each consisting of a skill and two progressive safety modifications. Gymnasts were instrumented with mouthpiece sensors embedded with an accelerometer and gyroscope collecting motion data at 200, 300, and 500 Hz during each skill performance. Peak-to-peak linear and rotational kinematics during contact phases and peak rotational kinematics during non-contact phases were computed. A mixed-effects model was used to compare differences in modification status nested within skill categories. Timer skills (i.e. drills that simulate performance of a gymnastics skill) resulted in the highest median ΔLA and ΔRA of all skill categories, and 132 skill performances exceeded 10 g ΔLA during a contact phase. Modifications were associated with significant reductions in head kinematics during contact phases of timers, floor skills, bar releases, and vault skills. Gymnasts can be exposed to direct and indirect head accelerations at magnitudes consistent with other youth contact sports, and common safety modifications may be effective at reducing head motion during contact and non-contact phases of gymnastics skills.

Neck Range of Motion Prognostic Factors in Association to Shoulder and Elbow Injuries in Professional Baseball Pitchers.

BACKGROUND: Authors have observed an association between cervical spine mobility and arm injury risk in baseball player; however, there is a need to assess the generalizability of cervical measurement data. Assessing the downstream of associations of cervical dysfunction on shoulder and elbow injuries can inform clinical interventions to help reduce future arm injuries. The purpose of this study was to assess the generalizability of neck range of motion measures as arm injury prognostic factors in professional baseball pitchers. METHODS: A prospective cohort of professional baseball pitchers in one Major League Baseball Organization was performed. Pitchers underwent pre-season neck range of motion including cervical flexion, extension, rotation, lateral flexion, and the flexion-rotation test (CFRT) and were followed for the season. The outcome was the occurrence of shoulder or elbow injury. A Cox proportional hazards analysis was performed and reported as hazard ratios (HR) with 95% confidence intervals (95% CI). RESULTS: A total of 88 pitchers were included (Age: 24.2 (2.4); Left-Handed: 21 (23%); Fastball Velocity: 92.3 (1.8)), with 15,942 athlete exposure days collected over the season. Pitcher neck range of motion was assessed (Flexion: 64 (10); Extension: 69 (11); Difference in Lateral Flexion: -1 (7); Difference in Neck Rotation: -2 (9); Difference in CFRT: -1 (7)). A total of 20 arm injuries (Shoulder: 9 (10%); Elbow: 11 (13%); Combined Rate: 1.3 (95% CI: 0.7, 1.7) per 1000 exposure days) were suffered by pitchers during the season. For every degree increase in the difference in dominant (rotating to dominant shoulder) versus non-dominant (rotating to non-dominant shoulder) neck rotation, there was a four-fold increase in arm injury hazard (HR: 4.0 (95% CI: 1.1, 13.9), p = 0.031). No other neck measurements demonstrated prognostic value. CONCLUSIONS: A deficit in dominant versus non-dominant neck rotation was prognostic for pitching arm injury. However, the cervical rotation test did not have prognostic value in this sample. Further research is required to assess the generalizability and scalability of neck range of motion assessment in relation to baseball shoulder and elbow injuries across different competition levels.

Presentation to the Emergency Department Increases the Likelihood of Surgical Management of Minimally Displaced Gartland Type IIa Pediatric Supracondylar Humerus Fractures.

BACKGROUND: Few studies have explored factors influencing the clinical decision-making process in the management of Gartland type IIa supracondylar humerus fractures (SCHFs). This study sought to determine whether the location of patient presentation and patient socioeconomic status are associated with the treatment of type IIa SCHFs. METHODS: This was a retrospective review of 262 patients younger than 13 years of age seen for acute Gartland type II SCHFs between 2012 and 2022. Pre-treatment radiographs were reviewed to measure Baumann angle and the location of the anterior humeral line relative to the capitellum. Demographic characteristics and socioeconomic status, measured through Child Opportunity Index (COI) scores, were generated and logistic regression analysis was performed to evaluate the relationship between location of presentation and fracture management. Logistic regressions were also used to evaluate the relationship between COI and location of presentation and treatment. RESULTS: 137 male and 125 female patients met the inclusion criteria with a mean age of 5.95 (0.13) years at the time of presentation. Presentation to the emergency department (ED) demonstrated reduced odds of closed reduction and casting compared to outpatient clinic presentation [0.13 (95% CI: 0.02-0.98), P=0.048]. 27.5% of minimally displaced fractures that presented to the ED and 20.0% of minimally displaced fractures that presented to an outpatient clinic were treated surgically. There was no association between COI and the location of patient presentation [1.2 (95% CI: 0.9-1.5), P=0.226] or treatment received [1.04 (95% CI: 0.48-2.26), P=0.922]. CONCLUSION: These results suggest that patients who present to the ED after type IIa SCHFs are more likely to receive surgical treatment. COI does not appear to be associated with the location of presentation or treatment received. LEVEL OF EVIDENCE: Prognostic level III.

Kinematic and Kinetic Differences Between Ball Rotational Exercises and the Throwing Motion in Collegiate Baseball Athletes.

ABSTRACT: Mylott, JA, Potts, EM, Wolf, JH, Bullock, GS, and Nicholson, KF. Kinematic and kinetic differences between ball rotational exercises and the throwing motion in collegiate baseball athletes. J Strength Cond Res XX(X): 000-000, 2024-The purpose of this study was to observe the associations that medicine ball pushes and chops have on the lower extremities regarding ground reaction forces (GRF) and lead knee flexion angles and to compare these values with a regular baseball overhead throw. Lower extremity kinetics and kinematics were obtained via force plates and marker motion capture. Subjects (n = 35) included baseball players (age 19.7 ± 1.5 years). Five medicine ball movements of each type along with at least 3 pitches or 5 throws off the mound were recorded for data collection. Statistical parametric mapping, including analysis of variance and 2-way t-tests, was used to compare the variables of interest between the movements for continuous time data. All kinematic and kinetic variables were significantly different (p < 0.05) for some time during the motion between the different trial types of medicine ball exercises and throws. A medicine ball chop can increase peak drive leg GRF, whereas a push can help an athlete keep greater driver leg GRF and maintain ground connection into foot plant. A push helps train lead leg deficiencies in the delivery. Both the medicine ball chop and push have benefits for training lead leg stabilization and extension.

Impact of Prolonged Sport Stoppage on Knee Injuries in High School Athletes: An Ecological Study.

CONTEXT: In March 2020, public health concerns resulted in school closure throughout the United States. The prolonged sport cessation may affect knee injury risk in high school athletes. The purpose of this study was to describe and compare risk of knee injuries in high school athletes during 2019-2020 and 2020-2021 academic years, and stratify by gender, severity, mechanism of injury, injury type, and knee anatomic region. DESIGN: Historical-prospective cohort study. METHODS: This historical-prospective cohort study included 176 schools in 6 states matched by sport participation in control and COVID years from July 1, 2019 to June 30, 2021. Injury rates per 1000 athletes per year were calculated with 95% confidence intervals. A negative binomial regression was performed to assess potential differences in knee injuries between academic years. RESULTS: 94,847 and 72,521 high school athletes participated in the 2019-2020 (19-20) and 2020-2021 (20-21) seasons. Knee injury risk was higher in the 20-21 season (19-20: 28.89% [27.82-29.96]; 20-21: 33.82% [32.50-35.14]). Risk increased for male athletes from 2019-2020 to 2020-2021 (19-20: 29.42% [28.01-30.83]; 20-21: 40.32% [38.89-41.75]). Female knee injury risk was similar between years (19-20: 25.78% [24.29-27.27]; 20-21: 26.03% [24.31-27.75]). Knee injuries increased by a ratio of 1.2 ([95% CI, 1.1-1.3], P < .001) during 2020-2021. CONCLUSIONS: Knee injury risk and relative risk increased among males in 2020-2021. Results indicate changes in knee injury risk following return from COVID shelter in place among high school athletes and implicate potential negative downstream effects of interrupted sports training and participation on high school injury risk.

Barriers and facilitators to implementation of musculoskeletal injury mitigation programmes for military service members around the world: a scoping review.

INTRODUCTION: Musculoskeletal injury (MSK-I) mitigation and prevention programmes (MSK-IMPPs) have been developed and implemented across militaries worldwide. Although programme efficacy is often reported, development and implementation details are often overlooked, limiting their scalability, sustainability and effectiveness. This scoping review aimed to identify the following in military populations: (1) barriers and facilitators to implementing and scaling MSK-IMPPs; (2) gaps in MSK-IMPP research and (3) future research priorities. METHODS: A scoping review assessed literature from inception to April 2022 that included studies on MSK-IMPP implementation and/or effectiveness in military populations. Barriers and facilitators to implementing these programmes were identified. RESULTS: From 132 articles, most were primary research studies (90; 68.2%); the remainder were review papers (42; 31.8%). Among primary studies, 3 (3.3%) investigated only women, 62 (69%) only men and 25 (27.8%) both. Barriers included limited resources, lack of stakeholder engagement, competing military priorities and equipment-related factors. Facilitators included strong stakeholder engagement, targeted programme design, involvement/proximity of MSK-I experts, providing MSK-I mitigation education, low burden on resources and emphasising end-user acceptability. Research gaps included variability in reported MSK-I outcomes and no consensus on relevant surveillance metrics and definitions. CONCLUSION: Despite a robust body of literature, there is a dearth of information about programme implementation; specifically, barriers or facilitators to success. Additionally, variability in outcomes and lack of consensus on MSK-I definitions may affect the development, implementation evaluation and comparison of MSK-IMPPs. There is a need for international consensus on definitions and optimal data reporting elements when conducting injury risk mitigation research in the military.

Oxidized Zirconium Versus Cobalt Chromium for Primary TKA: No Difference in Midterm Revision Rates From the American Joint Replacement Registry.

BACKGROUND: Cobalt chromium (CoCr) is the most commonly used material in TKA; however, the use of oxidized zirconium (OxZr) implants has increased. The advantages to this material demonstrated in basic science studies have not been borne out in clinical studies to date. QUESTION/PURPOSE: In the setting of the American Joint Replacement Registry (AJRR), how do revision rates differ between CoCr and OxZr after primary TKA? METHODS: The AJRR was accessed for all primary TKAs performed between 2012 and 2020 for osteoarthritis, resulting in 441,605 procedures (68,506 with OxZr and 373,099 with CoCr). The AJRR is the largest joint replacement registry worldwide and collects procedure-specific details, making it ideal for large-scale comparisons of implant materials in the United States. Competing risk survival analyses were used to evaluate the all-cause revision rates of primary TKAs, comparing CoCr and OxZr implants. Data from the Centers for Medicare and Medicaid Services claims from 2012 to 2017 were also cross-referenced to capture additional revisions from other institutions. Revision rates were tabulated and subclassified by indication. Multivariate Cox regression was used to account for confounding variables such as age, gender, region, and hospital size. RESULTS: After controlling for confounding variables, there were no differences between the OxZr and CoCr groups in terms of the rate of all-cause revision at a mean follow-up of 46 ± 23 months and 44 ± 24 months for CoCr and OxZr implants, respectively (hazard ratio 1.055 [95% confidence interval 0.979 to 1.137]; p = 0.16) The univariate analysis demonstrated increased rates of revisions for pain and instability in the OxZr group (p = 0.003 and p < 0.001, respectively). CONCLUSION: These findings suggest there is no difference in all-cause revision between OxZr and CoCr implants in the short-term to mid-term. However, further long-term in vivo studies are needed to monitor the safety and all-cause revision rate of OxZr implants compared with those of CoCr implants. OxZr implants may be favorable in patients who have sensitivity to metal. Despite similar short-term to mid-term all-cause revision rates to CoCr implants, because of the limitations of this study, definitive recommendations for or against the use of OxZr cannot be made. LEVEL OF EVIDENCE: Level III, therapeutic study.

Higher rates of concussion following COVID-19 infection in high school athletes.

OBJECTIVE: To compare concussion rates (CRs) over one academic year in high school athletes with and without a COVID-19 infection prior to concussion. METHODS: Illness and concussion were prospectively reported for male and female high school athletes across six states over one academic year in the Players Health Rehab surveillance system. Concussion was truncated to 60 days following recovery and return to sport from COVID-19. CRs were estimated per 1000 athletes per academic year and stratified by those who tested positive for COVID-19 infection (with COVID-19) and those who did not (no COVID-19). Poisson regression analyses estimated rate ratio (RR) of concussion controlling for state, gender and an offset of the log athlete participation (with COVID-19 and no COVID-19). RESULTS: Of 72 522 athletes, 430 COVID-19 infections and 1273 concussions were reported. The CR was greater in athletes who reported COVID-19 (CR=74.4/1000 athletes/year, 95% CI 49.6 to 99.3) compared with those who did not (CR=17.2, 95% CI 16.3 to 18.2). Athletes with recent COVID-19 had a threefold higher rate of concussion (RR=3.1, 95% CI 2.0 to 4.7). CONCLUSION: Athletes returning from COVID-19 had higher CRs than those who did not experience COVID-19. This may be related to ongoing COVID-19 sequelae or deconditioning related to reduced training and competition load during the illness and when returning to sport. Further research is needed to understand the association of recent COVID-19 infection and concussion in order to inform preventive strategies.

Improving Clinical Utility of Real-World Prediction Models: Updating Through Recalibration.

ABSTRACT: Bullock, GS, Shanley, E, Thigpen, CA, Arden, NK, Noonan, TK, Kissenberth, MJ, Wyland, DJ, and Collins, GS. Improving clinical utility of real-world prediction models: updating through recalibration. J Strength Cond Res 37(5): 1057-1063, 2023-Prediction models can aid clinicians in identifying at-risk athletes. However, sport and clinical practice patterns continue to change, causing predictive drift and potential suboptimal prediction model performance. Thus, there is a need to temporally recalibrate previously developed baseball arm injury models. The purpose of this study was to perform temporal recalibration on a previously developed injury prediction model and assess model performance in professional baseball pitchers. An arm injury prediction model was developed on data from a prospective cohort from 2009 to 2019 on minor league pitchers. Data for the 2015-2019 seasons were used for temporal recalibration and model performance assessment. Temporal recalibration constituted intercept-only and full model redevelopment. Model performance was investigated by assessing Nagelkerke's R-square, calibration in the large, calibration, and discrimination. Decision curves compared the original model, temporal recalibrated model, and current best evidence-based practice. One hundred seventy-eight pitchers participated in the 2015-2019 seasons with 1.63 arm injuries per 1,000 athlete exposures. The temporal recalibrated intercept model demonstrated the best discrimination (0.81 [95% confidence interval [CI]: 0.73, 0.88]) and R-square (0.32) compared with original model (0.74 [95% CI: 0.69, 0.80]; R-square: 0.32) and the redeveloped model (0.80 [95% CI: 0.73, 0.87]; R-square: 0.30). The temporal recalibrated intercept model demonstrated an improved net benefit of 0.34 compared with current best evidence-based practice. The temporal recalibrated intercept model demonstrated the best model performance and clinical utility. Updating prediction models can account for changes in sport training over time and improve professional baseball arm injury outcomes.

Long-term quality of life, work limitation, physical activity, economic cost and disease burden following ACL and meniscal injury: a systematic review and meta-analysis for the OPTIKNEE consensus.

OBJECTIVE: Determine the long-term health-related quality-of-life (HRQoL), work limitation, physical activity, health/economic cost and disease burden of traumatic ACL and/or meniscal injury. Findings will inform OPTIKNEE evidence-based consensus recommendations. DESIGN: Random-effects meta-analysis evaluated HRQoL (SF-36/SF-12/VR-12 Physical Component Scores (PCS) and Mental Component Scores (MCS), EuroQol-5D (EQ-5D)) stratified by time postinjury, and pooled mean differences (95% CI) between ACL-injured and uninjured controls. Other outcomes were synthesised descriptively. Risk-of-bias (RoB) and certainty of evidence (Grading of Recommendations Assessment, Development and Evaluation) were assessed. DATA SOURCES: MEDLINE, EMBASE, CENTRAL, SPORTDiscus, CINAHL searched inception: 22 November 2021. ELIGIBILITY: Studies reporting HRQoL, work limitations, physical activity levels, health/economic costs or disease burden, ≥2 years post-ACL and/or meniscal injury. RESULTS: Fifty studies were included (10 high-RoB, 28 susceptible-to-some-bias and 12 low-RoB). Meta-analysis (27 studies, very low certainty of evidence) estimated a pooled mean (95% CI) PCS of 52.4 (51.4 to 53.4) and MCS of 54.0 (53.0 to 55.0) 2-14 years post-ACL injury. Pooled PCS scores were worse >10 years (50.8 (48.7 to 52.9)) compared with 2-5 years (53.9 (53.1 to 54.7)) postinjury. Excluding high-RoB studies, PCS scores were worse in ACL-injured compared with uninjured controls (-1.5 (-2.9 to -0.1)). Six studies (low certainty of evidence) informed a pooled EQ-5D score of 0.83 (0.81 to 0.84). Some individuals experienced prolonged work absenteeism and modified activities ≥2 years post-ACL injury. ACL injury was associated with significant direct and indirect costs, and early ACL reconstruction may be less cost-effective than rehabilitation. Only three studies evaluated meniscal injury outcomes (all evaluated HRQoL). CONCLUSION: There is a very-low certainty of evidence that PCS scores ≥2 years post-ACL injury are worse than uninjured controls and decline over time, whereas MCS scores remain high. ACL injury can result in prolonged work absenteeism and high health/economic costs. Further studies are needed to determine the long-term burden of traumatic meniscal injury.

OPTIKNEE 2022: consensus recommendations to optimise knee health after traumatic knee injury to prevent osteoarthritis.

The goal of the OPTIKNEE consensus is to improve knee and overall health, to prevent osteoarthritis (OA) after a traumatic knee injury. The consensus followed a seven-step hybrid process. Expert groups conducted 7 systematic reviews to synthesise the current evidence and inform recommendations on the burden of knee injuries; risk factors for post-traumatic knee OA; rehabilitation to prevent post-traumatic knee OA; and patient-reported outcomes, muscle function and functional performance tests to monitor people at risk of post-traumatic knee OA. Draft consensus definitions, and clinical and research recommendations were generated, iteratively refined, and discussed at 6, tri-weekly, 2-hour videoconferencing meetings. After each meeting, items were finalised before the expert group (n=36) rated the level of appropriateness for each using a 9-point Likert scale, and recorded dissenting viewpoints through an anonymous online survey. Seven definitions, and 8 clinical recommendations (who to target, what to target and when, rehabilitation approach and interventions, what outcomes to monitor and how) and 6 research recommendations (research priorities, study design considerations, what outcomes to monitor and how) were voted on. All definitions and recommendations were rated appropriate (median appropriateness scores of 7-9) except for two subcomponents of one clinical recommendation, which were rated uncertain (median appropriateness score of 4.5-5.5). Varying levels of evidence supported each recommendation. Clinicians, patients, researchers and other stakeholders may use the definitions and recommendations to advocate for, guide, develop, test and implement person-centred evidence-based rehabilitation programmes following traumatic knee injury, and facilitate data synthesis to reduce the burden of knee post-traumatic knee OA.

A Higher Playing Standard, Bowling, and Intermittent Helmet Use Are Related to a Greater Odds of Injury or Concussion in Cricket.

OBJECTIVE: To determine if playing position, a higher playing standard, and nonhelmet use are related to an increased odds of joint-specific injury and concussion in cricket. DESIGN: Cross-sectional cohort. PARTICIPANTS: Twenty-eight thousand one hundred fifty-two current or former recreational and high-performance cricketers registered on a national database were invited to participate in the Cricket Health and Wellbeing Study. Eligibility requirements were aged ≥18 years and played ≥1 cricket season. INDEPENDENT VARIABLES: Main playing position (bowler/batter/all-rounder), playing standard (high-performance/recreational), and helmet use (always/most of the time/occasionally/never). MAIN OUTCOME MEASURES: Cross-sectional questionnaire data included cricket-related injury (hip/groin, knee, ankle, shoulder, hand, back) resulting in ≥4 weeks of reduced exercise and self-reported concussion history. Crude and adjusted (adjusted for seasons played) odds ratios and 95% confidence interval (CIs) were estimated using logistic regression. RESULTS: Of 2294 participants (59% current cricketers; 97% male; age 52 ± 15 years; played 29 ± 15 seasons; 62% recreational cricketers), 47% reported cricket-related injury and 10% reported concussion. Bowlers had greater odds of hip/groin [odds ratio (95% CI), 1.9 (1.0-3.3)], knee [2.0 (1.4-2.8)], shoulder [2.9 (1.8-4.5)], and back [2.8 (1.7-4.4)] injury compared with batters. High-performance cricketers had greater odds of injury and concussion than recreational cricketers. Wearing a helmet most of the time [2.0 (1.4-3.0)] or occasionally [1.8 (1.3-2.6)] was related to higher odds of self-reported concussion compared with never wearing a helmet. Concussion rates were similar in cricketers who always and never wore a helmet. CONCLUSIONS: A higher playing standard and bowling (compared with batting) were associated with greater odds of injury. Wearing a helmet occasionally or most of the time was associated with higher odds of self-reported concussion compared with never wearing a helmet.

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.

Pitching Biomechanics Normative Values and Kinetic Differences by Competition Level.

Pitching kinematic and kinetic assessments require normative values to make valuable comparisons to athletic peers. The purpose of this research note was to report normative values of pitching kinematics and kinetics and to compare kinetics by competition level. A retrospective review was performed on three-dimensional baseball pitching biomechanical evaluations. Kinematics and kinetics were calculated. Pitchers were portioned into competition level groups. Kinetic group differences were assessed through analyses of variance with significance level p < 0.05. One-hundred and twenty pitchers were included. Elbow varus torque was greater in higher competition levels. Shoulder distraction force was greater in higher competition levels. All levels demonstrated similar maximum vertical push off ground reaction force (p = 0.960) and maximum vertical landing ground reaction force (p = 0.135). Higher competition level pitchers demonstrated improved pitching kinematic efficiency compared to lower-level pitchers. However, college and professional pitchers exhibited greater arm stress, which may be attributed to increased pitching velocity. These pitching biomechanical data can be used as normative comparisons when examining pitching mechanics at multiple competition levels throughout an athlete's baseball career. (Journal of Surgical Orthopaedic Advances 31(3):177-180, 2022).

Does sex affect second ACL injury risk? A systematic review with meta-analysis.

OBJECTIVE: To determine sex-based differences in risk of a second ACL injury (overall and by laterality) following primary ACL reconstruction in athletes who are attempting to return to sport. DESIGN: Systematic review with meta-analysis. DATA SOURCES: Systematic search of five databases conducted in August 2019. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Studies reporting sex-based differences in the incidence of second ACL injury in athletes attempting to return-to-sports and who were followed for at least 1 year following primary ACL reconstruction. RESULTS: Nineteen studies were included in this review, with seven studies excluded from the primary meta-analysis due to high risk of bias. The remaining 12 studies (n=1431 females, n=1513 males) underwent meta-analysis, with all 19 studies included in a sensitivity analysis. Total second ACL injury risk was 21.9% (females: 22.8%, males: 20.3%). Females were found to have 10.7% risk of an ipsilateral ACL injury and 11.8% risk of a contralateral ACL injury. Males were found to have 12.0% risk of an ipsilateral ACL injury and 8.7% risk of a contralateral ACL injury. No statistically significant differences were observed for total second ACL injury risk (risk difference=-0.6%, 95% CI -4.9 to 3.7, p=0.783, I2=41%) or contralateral ACL injury risk (risk difference=1.9%, 95% CI -0.5% to 4.4%, p=0.113, I2=15%) between sexes. Females were found to have a 3.4% absolute risk reduction in subsequent ipsilateral ACL injury risk compared with males (risk difference=-3.4%, 95% CI -6.7% to -0.02%, p=0.037, I2=35%). CONCLUSION: Both sexes have >20% increased risk of experiencing a second ACL injury. Any difference in the absolute risk of either a subsequent ipsilateral or contralateral ACL injury between sexes appears to be small. REGISTRATION: PROSPERO (CRD42020148369).

Cementless unicompartmental knee replacement achieves better ten-year clinical outcomes than cemented: a systematic review.

PURPOSE: The aim of this study was to report and compare the long-term revision rate, revision indications and patient reported outcome measures of cemented and cementless unicompartmental knee replacements (UKR). METHODS: Databases Medline, Embase and Cochrane Central of Controlled Trials were searched to identify all UKR studies reporting the ≥ 10 year clinical outcomes. Revision rates per 100 component years [% per annum (% pa)] were calculated by fixation type and then, subgroup analyses for fixed and mobile bearing UKRs were performed. Mechanisms of failure and patient reported outcome measures are reported. RESULTS: 25 studies were eligible for inclusion with a total of 10,736 UKRs, in which there were 8790 cemented and 1946 cementless knee replacements. The revision rate was 0.73% pa (CI 0.66-0.80) and 0.45% pa (CI 0.34-0.58) per 100 component years, respectively, with the cementless having a significantly (p < 0.001) lower overall revision rate. Therefore, based on these studies, the expected 10-year survival of cementless UKR would be 95.5% and cemented 92.7%. Subgroup analysis revealed this difference remained significant for the Oxford UKR (0.37% pa vs 0.77% pa, p < 0.001), but for non-Oxford UKRs there were no significant differences in revision rates of cemented and cementless UKRs (0.57% pa vs 0.69% pa, p = 0.41). Mobile bearing UKRs had significantly lower revision rates than fixed bearing UKRs in cementless (p = 0.001), but not cemented groups (p = 0.13). Overall the revision rates for aseptic loosening and disease progression were significantly lower (p = 0.02 and p = 0.009 respectively) in the cementless group compared to the cemented group (0.06 vs 0.13% pa and 0.10 vs 0.21% pa respectively). CONCLUSIONS: Cementless fixation had reduced long-term revision rates compared to cemented for the Oxford UKR. For the non-Oxford UKRs, the revision rates of cementless and cemented fixation types were equivalent. Therefore, cementless UKRs offer at least equivalent if not lower revision rates compared to cemented UKRs. LEVEL OF EVIDENCE: III.

Reverse total shoulder arthroplasty clinical and patient-reported outcomes and complications stratified by preoperative diagnosis: a systematic review.

OBJECTIVE: This systematic review aimed to investigate differences in clinical outcomes, patient-reported outcomes (PROs), and complication types and rates among preoperative diagnoses following reverse total shoulder arthroplasty (RTSA): rotator cuff tear arthropathy, primary osteoarthritis, massive irreparable rotator cuff tear, proximal humeral fracture, rheumatoid arthritis (RA), and revision of anatomic arthroplasty (Rev). LITERATURE SEARCH: Three electronic databases were searched from inception to January 2020. STUDY SELECTION CRITERIA: The inclusion criteria were (1) patients with a minimum age of 60 years who underwent RTSA for the stated preoperative diagnoses, (2) a minimum of 2 years' follow-up, and (3) preoperative and postoperative values for clinical outcomes and PROs. DATA SYNTHESIS: Risk of bias was determined by the Methodological Index for Non-randomized Studies tool and the modified Downs and Black tool. Weighted means for clinical outcomes and PROs were calculated for each preoperative diagnosis. RESULTS: A total of 53 studies were included, of which 36 (68%) were level IV retrospective case series. According to the Methodological Index for Non-randomized Studies tool, 33 studies (62%) showed a high risk of bias; the 3 randomized controlled trials showed a low risk of bias on the modified Downs and Black tool. RTSA improved clinical outcomes and PROs for all preoperative diagnoses. The Rev group had poorer final outcomes as noted by a lower American Shoulder and Elbow Surgeons score (69) and lower pain score (1.8) compared with the other preoperative diagnoses (78-82 and 0.4-1.4, respectively). The RA group showed the highest complication rate (28%), whereas the osteoarthritis group showed the lowest rate (1.4%). CONCLUSION: Studies in the RTSA literature predominantly showed a high risk of bias. All preoperative diagnoses showed improvements; Rev patients showed the worse clinical outcomes and PROs, and RA patients showed higher complication rates. The preoperative diagnosis in RTSA patients can impact outcomes and complications.

Development and internal validation of a humeral torsion prediction model in professional baseball pitchers.

BACKGROUND: Humeral torsion (HT) has been linked to pitching arm injury risk after controlling for shoulder range of motion. Currently measuring HT uses expensive equipment, which inhibits clinical assessment. Developing an HT predictive model can aid clinical baseball arm injury risk examination. Therefore, the purpose of this study was to develop and internally validate an HT prediction model using standard clinical tests and measures in professional baseball pitchers. METHODS: An 11-year (2009-2019) prospective professional baseball cohort was used for this study. Participants were included if they were able to participate in all practices and competitions and were under a Minor League Baseball contract. Preseason shoulder range of motion (external rotation [ER], internal rotation [IR], horizontal adduction [HA]) and HT were collected each season. Player age, arm dominance, arm injury history, and continent of origin were also collected. Examiners were blinded to arm dominance. An a priori power analysis determined that 244 players were needed for accurate prediction models. Missing data was low (<3%); thus, a complete case analysis was performed. Model development followed the transparent reporting of a multivariable prediction model for individual prognosis or diagnosis (TRIPOD) recommendations. Regression models with restricted cubic splines were performed. Following primary model development, bootstrapping with 2000 iterations were performed to reduce overfitting and assess optimism shrinkage. Prediction model performance was assessed through root mean square error (RMSE), R2, and calibration slope with 95% confidence intervals (CIs). Sensitivity analyses included dominant and nondominant HT. RESULTS: A total of 407 professional pitchers (age: 23.2 [standard deviation 2.4] years, left-handed: 17%; arm history prevalence: 21%) participated. Predictors with the highest influence within the model include IR (0.4, 95% CI 0.3, 0.5; P < .001), ER (-0.3, 95% CI -0.4, -0.2; P < .001), HA (0.3, 95% CI 0.2, 0.4; P < .001), and arm dominance (right-handed: -1.9, 95% CI -3.6, -0.1; P = .034). Final model RMSE was 12, R2 was 0.41, and calibration was 1.00 (95% CI 0.94, 1.06). Sensitivity analyses demonstrated similar model performance. CONCLUSIONS: Every 3° of IR explained 1° of HT. Every 3° of ER explained 1° less of HT, and every 7° of HA explained 1° of HT. Right-handers had 2° less HT. Models demonstrated good predictive performance. This predictive model can be used by clinicians to infer HT using standard clinical test and measures. These data can be used to enhance professional baseball arm injury examination.

Health-related quality of life and flourishing in current and former recreational and elite cricketers.

BACKGROUND: Health related quality of life (HRQoL) and flourishing are constructs that encompasses a holistic representation of physical, psychological, and social health. The underlying psychological factors that can affect HRQoL and flourishing in sports participants is poorly understood. The purpose of this study was to i) evaluate HRQoL (physical and mental-components) and flourishing in recreational and elite and current and former cricketers; ii) determine the effect of resilience, playing-standard, and playing status on HRQoL and flourishing in cricketers. METHODS: The Cricket Health and Wellbeing Study (n = 2598 current and former cricketers, aged ≥18 years) collected cross-sectional questionnaire data including the Flourishing Scale, Short Form-8 (physical (PCS) and mental (MCS) component scores), resilience (European Social Survey), highest standard-of-play, and playing status. Multivariable linear regressions with fractional polynomials were utilised, adjusted for age, gender, total cricket-seasons, comorbidity, ≥ 4-week time-loss injury, and orthopaedic surgery. RESULTS: Two thousand two hundred eighty individuals (aged (mean (SD)) 51.7(14.7) years, 61% played recreationally, 37% former cricketers) were included in analyses. The median (IQR) PCS was 51.4(46.9-55.9), MCS was 54.3(50.0-58.6), and Flourishing Scale score was 48 [ (1-7)] .Greater resilience was associated with better PCS (effect (95% CI) 1.41(0.70-2.11)), MCS (4.78(4.09-5.48)), and flourishing (2.07(2.55-3.59)) compared to less resilience. Playing standard was not associated with HRQoL. Playing at an elite standard was associated with greater flourishing (1.21(0.68, 1.73)), compared with playing recreationally. Current cricket participation was associated with better PCS (3.61(2.92-4.30)) and flourishing scores (0.53(0.02-1.04)), compared to former cricket participation. CONCLUSION: Cricketers reported high levels of mental-components of HRQoL and flourishing, and this was similar in recreational, elite, current and former cricketers. Current cricket participation and a higher standard-of-play was associated with greater flourishing. Current cricket participation was also associated with better PCS, however playing-status was not related to MCS. Further research is needed to understand if cricket participation may have psychological benefits that persist beyond cricket retirement.