Relationships between throwing mechanics and shoulder anterior force in high school and professional baseball pitchers.

Background: Excessive shoulder anterior force has been implicated in pathology of the rotator cuff in little league and professional baseball pitchers; in particular, anterior laxity, posterior stiffness, and glenohumeral joint impingement. Distinctly characterized motions associated with excessive shoulder anterior force remain poorly understood. Methods: High school and professional pitchers were instructed to throw fastballs while being evaluated with 3D motion capture (480 Hz). A supplementary random forest model was designed and implemented to identify the most important features for regressing to shoulder anterior force, with subsequent standardized regression coefficients to quantify directionality. Results: 130 high school pitchers (16.3 ± 1.2 yrs; 179.9 ± 7.7 cm; 74.5 ± 12.0 kg) and 322 professionals (21.9 ± 2.1 yrs; 189.7 ± 5.7 cm; 94.8 ± 9.5 kg) were included. Random forest models determined nearly all the variance for professional pitchers (R2 = 0.96), and less than half for high school pitchers (R2 = 0.41). Important predictors of shoulder anterior force in high school pitchers included: trunk flexion at maximum shoulder external rotation (MER) (X.IncMSE = 2.4, ß = -0.23, p < 0.001), shoulder external rotation at ball release (BR)(X.IncMSE = 1.7, ß = -0.34, p < 0.001), and shoulder abduction at BR (X.IncMSE = 3.1, ß = 0.17, p < 0.001). In professional pitchers, shoulder horizontal adduction at foot contact (FC) was the highest predictor (X.IncMSE = 13.9, ß = 0.50, p < 0.001), followed by shoulder external rotation at FC (X.IncMSE = 3.6, ß = 0.26, p < 0.001), and maximum elbow extension velocity (X.IncMSE = 8.5, ß = 0.19, p < 0.001). Conclusion: A random forest model successfully selected a subset of features that accounted for the majority of variance in shoulder anterior force for professional pitchers; however, less than half of the variance was accounted for in high school pitchers. Temporal and kinematic movements at the shoulder were prominent predictors of shoulder anterior force for both groups. Clinical relevance: : Our statistical model successfully identified a combination of features with the ability to adequately explain the majority of variance in anterior shoulder force among high school and professional pitchers. To minimize shoulder anterior force, high school pitchers should emphasize decreased shoulder abduction at BR, while professionals can decrease shoulder horizontal adduction at FC.

Low Rates of Postoperative Complications and Revision Surgery After Primary Medial Elbow Ulnar Collateral Ligament Repair.

Purpose: To evaluate the incidence of early postoperative complications and revision surgery in patients who underwent primary medial ulnar collateral ligament (MUCL) repair with minimum of 2-year follow-up. Methods: A retrospective review of a national insurance database was conducted to identify patients with MUCL injuries who underwent primary MUCL repair between 2015 to 2020 with minimum 2-year follow-up. Patients >40 years of age and those who had concomitant elbow fractures or dislocations, lateral UCL injures, medial epicondylitis, elbow arthritis, or a history of previous elbow injury/surgery were excluded. The number of patients who underwent a concomitant ulnar nerve procedure (transposition or decompression) during the primary MUCL repair was recorded. Complications within 90 days of surgery and the incidence and timing of subsequent ipsilateral ulnar nerve surgery or revision MUCL surgery were assessed. Results: A total of 313 patients (63.6% male) were included. The mean age was 20.3 ± 6.9 years, and mean follow-up was 3.7 ± 1.3 years. Concomitant ulnar nerve transposition or decompression was performed in 34.2% (N = 107). The early postoperative complication rate was 7.3% (N = 23). The most common complication was ulnar neuropathy (5.8%, N = 18). Wound complications, elbow stiffness, and medial epicondyle fractures were much less common (N = 5). Sixteen of 18 (88.9%) patients with postoperative ulnar neuropathy underwent transposition or decompression at the time of primary repair. Of these 18 patients, 5 (27.8%) underwent a subsequent ulnar nerve surgery (1 primary and 4 secondary), with the majority occurring within 6 months. The incidence of revision MUCL surgery was low (1.0%, N=3), with all 3 patients undergoing MUCL reconstruction. Conclusion: There was a low incidence of early postoperative complications (7.3%) and 2-year revision MUCL surgery (1.0%) in young patients who underwent primary MUCL repair with no additional ligamentous, fracture, and dislocation-related diagnoses. All 3 (1.0%) MUCL revisions underwent reconstruction. Level of Evidence: Level IV, therapeutic case series.

Biomechanical Characteristics of Ulnar Collateral Ligament Injuries Treated With and Without Augmentation: A Network Meta-analysis of Controlled Laboratory Studies.

BACKGROUND: Treatment of ulnar collateral ligament (UCL) tears with suture tape augmentation has gained interest given preliminary reports of favorable biomechanical characteristics. No study to date has quantitatively assessed the biomechanical effects of multiple augmentation techniques relative to the native UCL. PURPOSE: To perform a systematic review and meta-analysis of controlled laboratory studies to assess and comparatively rank biomechanical effects of UCL repair or reconstruction with or without augmentation. STUDY DESIGN: Systematic review and meta-analysis; Level of evidence, 4. METHODS: PubMed, OVID/Medline, and Cochrane databases were queried in January 2023. A frequentist network meta-analytic approach was used to perform mixed-treatment comparisons of UCL repair and reconstruction techniques with and without augmentation, with the native UCL as the reference condition. Pooled treatment estimates were quantified under the random-effects assumption. Competing treatments were ranked in the network meta-analysis by using point estimates and standard errors to calculate P scores (greater P score indicates superiority of treatment for given outcome). RESULTS: Ten studies involving 206 elbow specimens in which a distal UCL tear was simulated were included. UCL reconstruction with suture tape augmentation (AugRecon) restored load to failure to a statistically noninferior magnitude (mean difference [MD], -1.99 N·m; 95% CI, -10.2 to 6.2 N·m; P = .63) compared with the native UCL. UCL reconstruction (Recon) (MD, -12.7 N·m; P < .001) and UCL repair with suture tape augmentation (AugRepair) (MD, -14.8 N·m; P < .001) were both statistically inferior to the native UCL. The AugRecon condition conferred greater load to failure compared with Recon (P < .001) and AugRepair (P = .002) conditions. AugRecon conferred greater torsional stiffness relative to all other conditions and was not statistically different from the native UCL (MD, 0.32 N·m/deg; 95% CI, -0.30 to 0.95 N·m/deg; P = .31). Medial ulnohumeral gapping was not statistically different for the AugRepair (MD, 0.30 mm; 95% CI, -1.22 to 1.82 mm; P = .70), AugRecon (MD, 0.57 mm; 95% CI, -0.70 to 1.84 mm; P = .38), or Recon (MD, 1.02 mm; 95% CI, -0.02 to 2.05 mm; P = .055) conditions compared with the native UCL. P-score analysis indicated that AugRecon was the most effective treatment for increasing ultimate load to failure and torsional stiffness, whereas AugRepair was the most effective for minimizing medial gapping. CONCLUSION: AugRecon restored load to failure and torsional stiffness most similar to the parameters of the native UCL, whereas Recon and AugRepair did not restore the same advantageous properties at time zero. Medial ulnohumeral gapping during a valgus load was minimized by all 3 treatments. Based on network interactions, AugRecon was the superior treatment approach for restoring important biomechanical features of the UCL at time zero that are jeopardized during a complete distal tear.

High Rate of Clinically Meaningful Achievement in Outcomes After Subacromial Balloon Spacer Implantation for Massive Irreparable Rotator Cuff Tears: A Systematic Review and Meta-analysis.

BACKGROUND: Subacromial balloon spacers have been introduced as a potential treatment option for patients with massive irreparable rotator cuff tears. However, it is important to comprehensively assess the clinical efficacy of this procedure in the context of an increasing amount of contemporary literature. PURPOSE: To perform a systematic review of the contemporary literature to understand the propensity for clinically meaningful improvements after subacromial balloon spacer implantation for massive irreparable rotator cuff tears. STUDY DESIGN: Systematic review and meta-analysis; Level of evidence, 4. METHODS: The PubMed, Ovid/MEDLINE, and Cochrane databases were queried in July 2022 for data pertaining to studies reporting clinically significant outcomes after subacromial balloon spacer implantation. Freeman-Tukey double arcsine transformation was used to quantify the pooled rate of clinically meaningful improvements in outcomes as evaluated using the minimal clinically important difference (MCID), Patient Acceptable Symptom State (PASS), and substantial clinical benefit (SCB). Qualitative analysis was performed when data were variably presented to avoid misleading reporting. RESULTS: There were 10 studies included, all of which reported MCID achievement. The overall pooled rate of MCID achievement for the Constant-Murley score was 83% (95% CI, 71%-93%; range, 40%-98%), with 6 of 8 studies reporting rates equal to or exceeding 85%. One study reported a 98% rate of PASS achievement for the Constant-Murley score at 3-year follow-up. The rate of MCID achievement for the American Shoulder and Elbow Surgeons (ASES) score ranged between 83% and 87.5%. The rate of PASS achievement for the ASES score was 56% at 2-year follow-up, while the rate of SCB achievement for the ASES score was 83% and 82% at 1- and 2-year follow-up, respectively. At 1-year follow-up, 74% and 78% of patients achieved the MCID for the Numeric Rating Scale and Oxford Shoulder Score, respectively. At 3 years, 69% of patients achieved the MCID for the Numeric Rating Scale and 87% achieved it for the Oxford Shoulder Score. CONCLUSION: Patients who underwent isolated subacromial balloon spacer implantation for massive irreparable rotator cuff tears demonstrated a high rate of clinically significant improvement in outcomes at short- to mid-term follow-up. A paucity of literature exists to appropriately define and evaluate the rates of achieving the PASS and SCB after subacromial balloon spacer implantation, necessitating further study.

Outcomes after débridement, antibiotics, and implant retention for prosthetic joint infection in shoulder arthroplasty.

BACKGROUND: Patients who undergo total shoulder arthroplasty usually have excellent long-term outcomes. However, a subset of patients is diagnosed with a prosthetic joint infection (PJI) requiring revision procedures and prolonged recovery. The purpose of this study was to evaluate rates of recurrent shoulder PJI in patients undergoing débridement, antibiotics, and implant retention (DAIR), single-stage revision, and 2-stage revision. We also sought to compare outcomes and complications across procedures. METHODS: Retrospective chart review was conducted for patients diagnosed with PJI after primary shoulder arthroplasty between January 2010 and August 2021. Patients were included if they underwent treatment with DAIR, single-stage revision, or 2-stage revision. Demographic information, surgical details, complications, laboratory data, postoperative antibiotic regimen, and infectious pathogen were collected. Postoperative patient-reported outcomes were collected: American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form, Single Assessment Numeric Evaluation, Shoulder Activity Scale, and PROMIS Upper Extremity. Chi-square, t test, and 1-way analysis of variance were used as appropriate to evaluate each factor. RESULTS: Sixty-five patients were included in the study, 26% treated with DAIR, 9% treated with single-stage revision, and 65% treated with 2-stage revision. There were no significant differences in patient comorbidities. Patients undergoing DAIR were diagnosed significantly earlier than those undergoing single- and 2-stage revision procedures (12.6 ± 22.9 months vs. 49.6 ± 48.4 vs. 25.0 ± 26.6, P = .010). Recurrent PJI was noted in 23.1% of patients: 29.4% of DAIR patients, no single-stage patients, and 23.8% of 2-stage patients (P = .330). Patients undergoing 2-stage revision with treatment failure had a significantly higher Elixhauser Comorbidity Index (0.2 ± 3.7 vs. 3.7 ± 3.9, P = .027). There was no significant difference in patient-reported outcomes across groups. CONCLUSION: Patients undergoing treatment of shoulder PJI with DAIR did not have an increased rate of reinfection compared with single-stage and 2-stage revision procedures. Patients treated with DAIR were diagnosed with PJI significantly earlier than those undergoing single-stage and 2-stage revision procedures. There was no difference in complication rates between groups. This information adds to the body of work detailing outcomes after DAIR for shoulder PJI and provides encouraging data for use in this patient population. Future studies with a larger sample size may be conducted to further investigate specific pathogens, infection timelines, and antibiotic regimens that reduce the risk of treatment failure.

Kinematic Parameters Predictive of Pitch Velocity in Youth to Professional Baseball Pitchers: A Qualitative Systematic Review.

Background: Specific kinematic factors have been found to contribute to faster pitch speeds, with poor mechanics leading to injury. Purpose: To discuss the kinematic parameters that predict faster ball velocity among baseball pitchers. Study Design: Systematic review. Methods: Using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, the authors utilized the Cochrane Database of Systematic Reviews, PubMed (2008-2019), and OVID/MEDLINE (2008-2019) databases. Eligible articles included those that reported on kinematic factors predictive of ball velocity across youth, high school, collegiate, and professional levels of play. The quality of all included studies was evaluated by 2 reviewers using the Appraisal tool for Cross-Sectional Studies (AXIS). The lack of consistent study design or outcome variables precluded meta-analysis. Results: A total of 584 studies were identified from the initial search with 12 included in final analysis (930 pitchers in total; 429 [46.1%] youth, 164 [17.6%] high school, 153 [16.5%] collegiate and 184 [19.8%] professional) with mean ball velocity of 71.1 mph (114.4 km/h). The average AXIS score was 16 out of a possible 20. The shoulder played a significant role in the generation of velocity-induced torques. Hip and shoulder separation was associated with a 2.6 ± 0.5 mph (4.1 ± 0.8 km/h) increase in velocity, whereas increased shoulder movement of the nonthrowing arm was negatively correlated with initial ball velocity (r2 = 0.798). Furthermore, hip/shoulder separation, decreased movement of the nonthrowing shoulder, trunk power and timing of maximum trunk rotation, increased contralateral trunk tilt and increased sagittal-plane trunk tilt, and decreased knee flexion at ball release were all associated with higher fastball speeds. Conclusion: Multiple upper extremity and trunk kinematic parameters affect ball velocity, with significant contributions from the throwing shoulder and trunk, as well as nondominant arm. Understanding kinematic predictors of faster ball velocity can help guide training regimens.

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.

Golfing after Orthopaedic Surgery: A longitudinal follow-up (GOLF) study protocol.

Aims: The primary aim of this prospective, multicentre study is to describe the rates of returning to golf following hip, knee, ankle, and shoulder arthroplasty in an active golfing population. Secondary aims will include determining the timing of return to golf, changes in ability, handicap, and mobility, and assessing joint-specific and health-related outcomes following surgery. Methods: This is a multicentre, prospective, longitudinal study between the Hospital for Special Surgery, (New York City, New York, USA) and Edinburgh Orthopaedics, Royal Infirmary of Edinburgh, (Edinburgh, UK). Both centres are high-volume arthroplasty centres, specializing in upper and lower limb arthroplasty. Patients undergoing hip, knee, ankle, or shoulder arthroplasty at either centre, and who report being golfers prior to arthroplasty, will be included. Patient-reported outcome measures will be obtained at six weeks, three months, six months, and 12 months. A two-year period of recruitment will be undertaken of arthroplasty patients at both sites. Conclusion: The results of this prospective study will provide clinicians with accurate data to deliver to patients with regard to the likelihood of return to golf and timing of when they can expect to return to golf following their hip, knee, ankle, or shoulder arthroplasty, as well as their joint-specific functional outcomes. This will help patients to manage their postoperative expectations and plan their postoperative recovery pathway.

Forearm Pronation at Foot Contact: A Biomechanical Motion-Capture Analysis in High School and Professional Pitchers.

Background: It has previously been speculated that baseball pitchers who display excessive forearm pronation at foot contact (FC) have a higher propensity toward ulnar collateral ligament injury and subsequent surgery. Purpose: To evaluate the association between degree of forearm pronation/supination at FC and throwing arm kinetics in high school and professional pitchers, at both the individual (intrapitcher) and the group (interpitcher) level. Study Design: Descriptive laboratory study. Methods: High school (n = 41) and professional (n = 196) pitchers threw 8 to 12 fastballs while being assessed with a 3-dimensional motion-capture system (480 Hz). Pitchers at each playing level were divided into a supination or pronation subgroup depending on degree of forearm pronation at FC. Regression models were built to observe the relationship between forearm pronation at FC and kinetic and kinematic parameters of interest. Results: At both the individual and the group level of high school and professional pitchers, there was no significant correlation between forearm pronation at FC and elbow varus torque (P min = .21). For every 10° increase in forearm pronation at FC in the individual high school pitcher, elbow flexion at FC decreased by 5°, whereas maximum elbow extension velocity was achieved 0.6% later in the pitch. In addition, elbow medial force increased by 4.1 N and elbow varus torque increased by 0.8 N·m for every 10° increase in forearm supination at FC. For every 10° increase in forearm supination in the individual professional pitcher, ball velocity increased by 0.5 m/s, shoulder external rotation at FC decreased by 11°, and elbow medial force decreased by 5.5 N. Conclusion: Supination- or pronation-predominant forearm motion during the pitch did not significantly differ between playing levels. Excessive forearm pronation at FC was not a significant risk factor for increased throwing arm kinetics for high school or professional pitchers. There was a weak positive association between forearm supination at FC and elbow varus torque in the individual high school pitcher. Ultimately, coaches and pitchers may be better served by redirecting their focus to other mechanical aspects of the pitch that may have stronger associations with injury risk implications as well as performance.

Artificial intelligence for automated identification of total shoulder arthroplasty implants.

BACKGROUND: Accurate and rapid identification of implant manufacturer and model is critical in the evaluation and management of patients requiring revision total shoulder arthroplasty (TSA). Failure to correctly identify implant designs in these circumstances may lead to delay in care, unexpected intraoperative challenges, increased morbidity, and excess health care costs. Deep learning (DL) permits automated image processing and holds the potential to mitigate such challenges while improving the value of care rendered. The purpose of this study was to develop an automated DL algorithm to identify shoulder arthroplasty implants from plain radiographs. METHODS: A total of 3060 postoperative images from patients who underwent TSA between 2011 and 2021 performed by 26 fellowship-trained surgeons at 2 independent tertiary academic hospitals in the Pacific Northwest and Mid-Atlantic Northeast were included. A DL algorithm was trained using transfer learning and data augmentation to classify 22 different reverse TSA and anatomic TSA prostheses from 8 implant manufacturers. Images were split into training and testing cohorts (2448 training and 612 testing images). Optimized model performance was assessed using standardized metrics including the multiclass area under the receiver operating characteristic curve (AUROC) and compared with a reference standard of implant data from operative reports. RESULTS: The algorithm classified implants at a mean speed of 0.079 seconds (±0.002 seconds) per image. The optimized model discriminated between 8 manufacturers (22 unique implants) with AUROCs of 0.994-1.000, accuracy of 97.1%, and sensitivities between 0.80 and 1.00 on the independent testing set. In the subset of single-institution implant predictions, a DL model identified 6 specific implants with AUROCs of 0.999-1.000, accuracy of 99.4%, and sensitivity >0.97 for all implants. Saliency maps revealed key differentiating features across implant manufacturers and designs recognized by the algorithm for classification. CONCLUSION: A DL model demonstrated excellent accuracy in identifying 22 unique TSA implants from 8 manufacturers. This algorithm may provide a clinically meaningful adjunct in assisting with preoperative planning for the failed TSA and allows for scalable expansion with additional radiographic data and validation efforts.

Management of Shoulder Instability in Patients with Seizure Disorders.

PURPOSE OF REVIEW: Patients with seizure disorders commonly suffer shoulder dislocations and subsequent instability. Due to high rates of recurrence and bone loss, management of this instability and associated pathology has proven to be more complex than that of patients without seizure disorders. The ultimate goal of this review is to outline the various treatment modalities and their respective outcomes in this complex patient population. RECENT FINDINGS: Optimization of medical management of seizure disorders is imperative. However, despite these efforts, the incidence of post-operative seizure activity continues to be a concern. These subsequent episodes increase the risk of further instability and failure of surgical procedures. Overall, the use of soft tissue procedures has proven to result in increased recurrence of instability compared to bone-block augmenting and grafting procedures. There are a variety of bone-block procedures that have been described for anterior and posterior instability. Despite their success in decreasing further instability, they are associated with several complications that patients should be informed of. There is no consensus regarding the optimal surgical management of shoulder instability in patients with seizure activity. A multidisciplinary approach to the management of the seizure activity is paramount to the success of their treatment. Further studies are required to evaluate the optimal timing and type of surgical intervention for individualized cases.

Subacromial Balloon Spacer Implantation for Massive Irreparable Rotator Cuff Tears Is Associated With Restoration of the Acromiohumeral Interval and Glenohumeral Center of Pressure: A Systematic Review and Meta-Analysis of Controlled Laboratory Studies.

BACKGROUND: Biodegradable subacromial balloon spacers (SBSs) have become increasingly used for the treatment of massive irreparable rotator cuff tears given their theorized clinical benefits; however, the relationship between biomechanical functions of the balloon spacer and clinical benefits remains unclear. PURPOSE: To perform a systematic review and meta-analysis of controlled laboratory studies investigating the use of SBSs for massive irreparable rotator cuff tears. STUDY DESIGN: Systematic review and meta-analysis; Level of evidence, 4. METHODS: PubMed, OVID/Medline, and Cochrane databases were queried in July 2022 for biomechanical data pertaining to SBS implantation in cadaveric models of irreparable rotator cuff tears. Random-effects meta-analysis of continuous outcomes using the DerSimonian-Laird method was performed to estimate pooled-treatment effect sizes between the irreparable rotator cuff tear state and the state in which an SBS was implanted. Data reported variably or in formats not amenable to analysis were presented descriptively. RESULTS: Five studies involving 44 cadaveric specimens were included. At 0° of shoulder abduction, SBS implantation resulted in a mean inferior humeral head translation of 4.80 mm (95% CI, 3.20-6.40; P < .001) relative to the irreparable rotator cuff tear state. This decreased to 4.39 mm and 4.35 mm at 30° and 60° of abduction, respectively. At 0° of abduction, implantation of an SBS was associated with a 5.01-mm (95% CI, 3.56-6.46, P < .001) anterior translation of the glenohumeral center of contact pressure relative to the irreparable tear state. This translation changed to 5.11 mm and 5.49 mm at 30° and 60° of abduction. In 2 studies, SBS implantation restored the glenohumeral contact pressure to that of the intact state and significantly reduced subacromial pressure distribution over a rotator cuff repair state. In 1 study, a high balloon fill volume (40 mL) resulted in a significant 10.3 ± 1.4-mm more anterior humeral head position relative to the intact cuff state. CONCLUSION: SBS implantation in cadaveric models of irreparable rotator cuff tears results in significant improvements in humeral head position at 0°, 30°, and 60° of shoulder abduction. Balloon spacers may also improve glenohumeral and subacromial contact pressures, although insufficient evidence currently exists to corroborate these findings. High balloon fill volumes (40 mL) may confer supraphysiologic anteroinferior translation of the humeral head.

Association Between Limited English Language Proficiency and Disparities in Length of Stay and Discharge Disposition After Total Shoulder Arthroplasty: A Retrospective Cohort Study.

Background: Limited English language proficiency in patients undergoing total shoulder arthroplasty (TSA) may make treatment more challenging. Purpose: We sought to investigate the potential association between TSA patients' use of a language interpreter and 2 outcomes: hospital length of stay (LOS) and discharge disposition. Methods: We conducted a retrospective cohort study comparing LOS and discharge disposition after TSA for patients who required interpreter services and patients who did not at a single institution in an urban setting between 2016 and 2020. Consecutive patients requiring interpreter services who underwent TSA were matched 1:1 to patients who did not require an interpreter by age, body mass index (BMI), sex, and procedure. Multivariate regression models controlling for age, BMI, sex, smoking, opioid use, white or non-white race, procedure, and diagnosis were constructed to determine associations between interpreter use, LOS, and discharge disposition. Results: Forty-one patients were included in each cohort, exceeding the minimum number required per an a priori power analysis. Mean hospital LOS was longer in the interpreter cohort than in the non-interpreter cohort (2.8 ± 2.4 vs 1.8 ± 1.0 days, respectively). Multivariate linear regression demonstrated interpreter use was the strongest predictor of LOS, with the effect estimate indicating an additional 0.88-day LOS per patient. A greater proportion of patients from the interpreter cohort were discharged to an acute/subacute rehabilitation facility than patients from the non-interpreter cohort (n = 8 [19.5%] vs n = 2 [4.9%], respectively). Patients from the interpreter cohort were 454% more likely to be discharged to acute/subacute rehabilitation facilities. Conclusions: Our retrospective analysis of patients undergoing TSA suggests that the need for interpreter services may be associated with increased LOS and discharge to a facility. More rigorous study is needed to identify the factors that influence these outcomes and to avoid disparities in hospital stay and discharge.

A Systematic Review of Lower-Body Kinematic and Strength Factors Associated With Pitch Velocity in Adult Baseball Pitchers.

CONTEXT: Ball velocity for baseball pitchers is influenced by a multitude of factors along the kinetic chain. While a vast amount of data currently exist exploring lower-extremity kinematic and strength factors in baseball pitchers, no previous study has systematically reviewed the available literature. OBJECTIVE: The aim of this systematic review was to perform a comprehensive assessment of the available literature investigating the association between lower-extremity kinematic and strength parameters and pitch velocity in adult pitchers. EVIDENCE ACQUISITION: Cross-sectional studies that investigated the association between lower-body kinematic and strength factors and ball velocity in adult pitchers were selected. A methodological index for nonrandomized studies checklist was used to evaluate the quality of all included studies. EVIDENCE SYNTHESIS: Seventeen studies met the inclusion criteria comprising a total of 909 pitchers (65%, professional, 33% college, and 3% recreational). The most studied elements were hip strength and stride length. The mean methodological index for nonrandomized studies score was 11.75 of 16 (range = 10-14). Pitch velocity was found to be influenced by several lower-body kinematic and strength factors including the following: (1) hip range of motion and strength of muscles around the hip and pelvis, (2) alterations in stride length, (3) alterations in lead knee flexion/extension, and (4) several pelvic and trunk spatial relationships throughout the throwing phase. CONCLUSIONS: Based on this review, we conclude that hip strength is a well-established predictor of increased pitch velocity in adult pitchers. Further studies in adult pitchers are needed to elucidate the effect of stride length on pitch velocity given mixed results across multiple studies. This study can provide a basis for trainers and coaches to consider the importance of lower-extremity muscle strengthening as a means by which adult pitchers can improve pitching performance.

Factors associated with humeral stem revision in anatomic to reverse total shoulder arthroplasty revision.

BACKGROUND: Recent advances in implant technology have allowed for modular or platform humeral stem insertion during initial anatomic total shoulder arthroplasty (TSA). These systems allow for humeral stem retention during conversion to reverse TSA (RTSA). However, some patients still require humeral stem revision when undergoing revision to RTSA. The purpose of this study was to evaluate the association between patient-specific factors and radiographic parameters with humeral stem revision vs. retention during conversion from TSA to RTSA. METHODS: Retrospective chart review was conducted for patients who underwent a revision TSA to RTSA between January 2010 and May 2022 at a single institution. Patients were included if their prosthesis included a convertible humeral stem. Patient demographic information, surgical details, and postoperative outcomes and complications were collected. Radiographic parameters were measured by 2 graders on radiographs taken prior to the revision procedure. The need for humeral stem revision and American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) scores (preoperative and 2 years) were also noted. Statistical analysis was performed using chi-square test for categorical variables and t test for continuous variables. RESULTS: One hundred seven patients were included, with 52 undergoing humeral stem revision. Patients were revised an average of 51.0 ± 54 months after primary TSA. Younger patient age (63.6 vs. 68.5 years, P = .017) and use of a lateralized glenosphere (1.6 mm vs. 0.4 mm, P < .001) were significantly associated with need for humeral stem revision. Glenoid to humeral head cut distance (28.3 mm vs. 26.3 mm, P = .076) approached significant association with the need for humeral stem revision. All other measurements were not associated with the need for humeral stem revision. Improvement of ASES scores at 2 years' follow-up was higher in the nonrevised group (increase of 33.4 points) than the revision group (23.3), but this did not reach significance (P = .149). Estimated blood loss and surgical time were significantly higher in the stem revision group than the non-revised group (P = .048 and P < .001, respectively). CONCLUSION: Younger patients and those receiving a lateralized glenosphere were more likely to undergo humeral stem revision during conversion from TSA to RTSA. Glenoid to the humeral head cut distance should be studied further as a potential indication for humeral stem revision, as it correlates with the space available for a revision implant. This information can guide surgeons with preoperative planning for a revision arthroplasty.

American Shoulder and Elbow Surgeons SLAP/Biceps Anchor Study Group evidence review: pathoanatomy and diagnosis in clinically significant labral injuries.

Glenoid superior biceps-labral pathology diagnosis, treatment, and outcomes are an evolving area of shoulder surgery. Historically, described as superior labrum anterior posterior (SLAP) tears, these lesions were identified as a source of pain in throwing athletes. Diagnosis and treatments applied to these SLAP lesions resulted in less than optimal outcomes in some patients and a prevailing sense of confusion. The purpose of this paper is to perform a reappraisal of the anatomy, examination, imaging, and diagnosis by the American Shoulder and Elbow Surgeons/SLAP biceps study group. We sought to capture emerging concepts and suggest a more unified approach to evaluation and identify specific needs for future research.

A Number of Modifiable and Nonmodifiable Factors Increase the Risk for Elbow Medial Ulnar Collateral Ligament Injury in Baseball Players: A Systematic Review.

PURPOSE: To analyze the current literature regarding risk factors associated with medial ulnar collateral ligament (MUCL) injury in baseball players and to serve as a robust source for identifying modifiable risk factors that once optimized, have the potential to reduce injury risk. METHODS: Comprehensive search of the available literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Studies were included if they evaluated risk factors for MUCL injuries in the elbow of baseball players. Risk of bias assessment was performed via Methodological Index for Non-randomized Studies (MINORS) scoring system. The Oxford Centre for Evidence-Based Medicine was used to determine level of evidence. Variables of interest; player age, position, shoulder motion, humeral retrotorsion, joint laxity, strength, balance, geography, velocity, pitch count, pitch types, throwing volumes, and throwing mechanics were recorded. RESULTS: Twenty-one studies were included in this systematic review. MINORS scores ranged from 75 to 87%, and variables demonstrated significant heterogeneity. Performance-based risk factors for MUCL injury included: increased pitch count (both annual and per game), higher percentage of fastballs thrown, smaller pitch repertoire, and/or a loss of pitching velocity. Biomechanical studies demonstrated the relationship between decreased shoulder range of motion (total ROM, ER, IR, and abduction), increased humeral retrotorsion, increased elbow valgus opening in the throwing arm, lower Y-Balance score, and increased lateral release position to increased MUCL injury. CONCLUSIONS: Risk factors for MUCL injury can generally be categorized into 4 primary groups: 1) various player demographics and characteristics, 2) throwing too hard (high velocity), 3) throwing too much (pitch count/volume), and 4) throwing with poor mechanics. In this systematic review, the most significant nonmodifiable risk factors for MUCL injuries included: increased glenohumeral retrotorsion and elbow valgus opening. The most consistent modifiable risk factors included: total shoulder range of motion, pitch count, pitch selection, Y balance score, and lateral release position. Pitch velocity was inconsistent in literature, but most studies found this as a risk for injury. These risk factors may serve as appropriate targets for future evidence-based injury mitigation strategies. LEVEL OF EVIDENCE: Level IV, systematic review of Level II-IV studies.

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.

Rate and Timing of Return to Golf After Hip, Knee, or Shoulder Arthroplasty: A Systematic Review and Meta-analysis.

BACKGROUND: The physical and mental health benefits of golf are well recognized, and as a moderate-intensity activity, it is an ideal sport for patients after joint arthroplasty. PURPOSE: To assess the rate and timing of returning to golf and the factors associated with these after hip, knee, or shoulder arthroplasty. STUDY DESIGN: Meta-analysis; Level of evidence, 4. METHODS: A search of PubMed and Medline was performed in March 2021 in line with the 2009 PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. Search terms included sport, golf, and arthroplasty. The criterion for inclusion was any published research article studying return to golf after arthroplasty. Random-effects modeling was used to measure rates of returning to golf for each type of arthroplasty. RESULTS: A total of 23 studies were included for review. All studies were retrospective in their methodology. The mean age of patients was 66.8 years (SD, 3.37). Four studies reported on hip arthroplasty, 6 on knee arthroplasty, and 13 on shoulder arthroplasty. Among 13 studies, the mean rate of returning to golf was 80% (95% CI, 70%-89.9%). Hip, knee, and shoulder arthroplasty had mean return rates of 90% (95% CI, 82%-98%), 70% (95% CI, 39%-100%), and 80% (95% CI, 68%-92%), respectively. Among 9 studies, the mean time to return to golf was 4.4 months (95% CI, 3.2-6). Change in handicap was reported in 8 studies (35%) with a mean change of -0.1 (95% CI, -2.4 to +2.2). There were no studies presenting factors associated with return to golf. CONCLUSION: This is the first meta-analysis of returning to golf after joint arthroplasty. The study reports a high rate of returning to golf, which was greatest after hip arthroplasty. However, the study highlights the paucity of prospective data on demographic, surgical, and golf-specific outcomes after arthroplasty. Future prospective studies are required to eliminate response bias and accurately capture golf and patient-specific outcomes.

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.