Melatonin: Evolving Physiological Understanding and Potential Therapeutic Role in Pain Medicine Including Intervertebral Disc Degeneration.

BACKGROUND: Melatonin, one of the most versatile hormones in the body, is well appreciated in managing circadian rhythm and for antioxidant properties. Produced in the pineal gland and within mitochondria, melatonin influences many physiologic processes through receptor mediated and direct effects. OBJECTIVE: The present investigation explores the evolving pharmacologic properties of melatonin, as well as current therapeutic uses in areas where mitigating oxidative stress, inflammation, and cellular senescence. This review also delves into novel therapeutic potential of melatonin and how current research is revealing a wide array of therapeutic promise in pain medicine. STUDY DESIGN: A systematic review of randomized controlled trials (RCTs) and observational studies was performed using various search engines focused on melatonin and its role in pain medicine. METHODS: The available literature on melatonin and pain medicine was reviewed. A comprehensive literature search of multiple databases from 1966 to July 2024, including manual searches of the bibliography of known review articles was performed. Quality assessment of the included studies and best evidence synthesis were incorporated into qualitative and quantitative evidence synthesis. OUTCOME MEASURES: The primary outcome measure was the proportion of patients receiving melatonin with significant relief and functional improvement of greater than 50% of at least 3 months. Duration of relief was categorized as short-term (less than 6 months) and long-term (greater than 6 months). RESULTS: Melatonin can affect intervertebral disc (IVD) health through the enhancement of survival and function of nucleus pulposus cells, primarily through activation of the ERK1/2 signaling pathway. Melatonin also influences the biochemical environment of the IVD by modulating inflammation and oxidative stress, crucial factors in the pathogenesis of disc degeneration. Melatonin has been shown to reduce senescence and promote autophagy within disc cells, vital for clearing out damaged cellular components, preserving cellular function and preventing deterioration associated with aging and degenerative diseases. LIMITATIONS: Despite the availability of multiple studies, the paucity of clinical pain related literature is considered as the major drawback. CONCLUSION: Based on the present systematic review, melatonin plays a critical role in sleep, but evolving studies have demonstrated substantive roles in mitigating degenerative conditions in various tissues, including IVD degeneration. Ongoing studies will better clarify the role of melatonin as a potential therapeutic agent, including the targeted delivery to various body regions.

Posterior Sacroiliac Fusion Surgery: A Retrospective Single Center Study.

BACKGROUND: Chronic sacroiliitis has variable etiologies with numerous treatments of varying efficacy. In recent years, a novel posterior approach utilizing bone matrix has been developed although to date, there is limited data in the literature regarding efficacy and safety through this approach. Benefits described include reduced adverse outcomes and quicker recovery when compared to the lateral approach. OBJECTIVE: The present investigation focused on sacroiliac joint fusion through the posterior approach and outcomes including disability, pain, and use of analgesics post-surgery. STUDY DESIGN: This retrospective, single-center study was conducted evaluating safety and efficacy of sacroiliac fusion allograft implants (LinQ Implant System from PainTEQ; PsiF System from Omnia Medical). METHODS: A total of 72 posterior approach sacroiliac joint fusions were performed. Fifty-three individuals were enrolled and followed at LSU Health Shreveport as the sole investigational site between August 2020 and June 2024. Selected participant age ranged between 28 and 79 years, with a mean age of 53.4 years. The LinQ Implant System was the primary surgical hardware selected for implantation (83.0%), with the PsiF System chosen in the remaining cases. OUTCOME MEASURES: VAS Scores, disability changes, adverse outcomes, and analgesic use were compared after sacroiliac joint fusion via the posterior approach. RESULTS: Mean VAS Scores for SIJ Pain Intensity significantly decreased by 3.6 cm from a baseline score of 9.5 cm by the Specified End (June 1st, 2024). In this regard, 65.4% of patients experienced a 20% or greater improvement in pain, 38.5% of patients experienced a 50% or greater improvement in pain, and 26.9% of patients experienced a 70% or greater improvement in pain.  Zero (0) procedure-related adverse events nor intra- or post-operative complications occurred throughout the duration of the investigation. LIMITATIONS: Retrospective nature of the study without a control group. Fifty-four percent (39 of 72) completed minimum one year follow up. Further, the withdrawal rate was 26%. CONCLUSION: The results of the present investigation demonstrated effective outcomes with minimal adverse effects and improvements in disability over a three-year period in the largest single center study to date involving posterior approach sacroiliac joint fusion.

On the Concerning Early Failure of a Short Stem Press-Fit Humeral Component.

INTRODUCTION: Anatomic total shoulder arthroplasty (TSA) is a common surgical intervention for various shoulder pathologies, predominantly glenohumeral osteoarthritis. While generally considered safe and effective, complications remain a challenge. Short stem implants, aim to preserve bone stock and reduce complications. However, concerns about a specific short stem implant (Univers Apex; Arthrex, Naples, FL, USA) have surfaced due to high reported rates relatively early aseptic loosening. METHODS: This retrospective study analyzed 116 consecutive TSA patients with Univers Apex implants from 2004 to 2022. 15 revision cases were assessed for radiographic loosening, and explanted implants were examined for damage using a 0-3 scale. Histopathological analysis evaluated cellular responses to wear debris. RESULTS: Of the patients, 13% (15/116) required revision at 23.2 months on average. A distinct radiographic loosening pattern was identified, with humeral component subsidence and thinning of the proximal humeral cortex. Histopathology revealed a robust inflammatory response to wear debris, with a potential association between macrophage infiltration, hinge damage, and polyethylene wear. CONCLUSION: This study reveals a notable rate of early aseptic humeral loosening with the Univers Apex short stem implant, emphasizing concerns raised in previous reports and providing a potential explanation for the high rate of early failure. Surgeons should exercise caution and closely monitor patients with this implant design.

Influence of Lead Knee Extension on Ball Velocity and Elbow Varus Torque in Professional and High School Baseball Pitchers.

Background: When the lead leg of a pitcher contacts the ground, the knee braces and then rapidly extends, initiating energy transfer to begin pelvis and trunk rotation. Purpose: To investigate the relationship of lead knee extension during the pitching delivery with peak lead knee extension velocity, ball velocity, and elbow varus torque in high school and professional pitchers. Study Design: Descriptive laboratory study. Methods: Data from 50 professional (PRO) and 50 high school (HS) pitcher groups were retrospectively analyzed. Pitchers threw 8 to 12 fastballs under 3-dimensional motion analysis (480 Hz). The groups were divided according to high or low lead knee extension: PRO-high (n = 18), PRO-low (n = 16), HS-high (n = 16), and HS-low (n = 17). Lead knee flexion, lead knee extension velocity, ball velocity, and elbow varus torque were analyzed between groups. Regression analyses were performed to quantify associations between lead knee extension and ball velocity and elbow varus torque for all pitchers. Results: At foot contact, all pitchers landed with similar knee flexion. PRO-high and HS-high pitchers had significantly greater lead knee extension through remaining pitching time points compared with the PRO-low and HS-low pitchers. PRO-high pitchers had faster ball velocity than PRO-low pitchers (39.8 ± 1.1 vs 39.3 ± 1.3 m/s, respectively), and HS-high pitchers had faster ball velocity than HS-low pitchers (34.1 ± 2.6 vs 31.2 ± 1.8 m/s, respectively) (P < .05). PRO-high pitchers had decreased elbow varus torque compared with PRO-low pitchers (85.3 ± 10.7 vs 95.4 ± 13.3 N·m, respectively); conversely, HS-high pitchers had greater elbow varus torque than HS-low pitchers (64.2 ± 14.7 vs 56.3 ± 12.2 N·m, respectively). For every 1° increase in lead knee extension, ball velocity increased by 0.47 m/s (P < .001) and elbow varus torque increased by 0.27 N·m (P = .025). Conclusion: Proper lead knee extension allowed efficient energy transfer through the kinetic chain to produce optimal ball velocity and minimize elbow varus torque in professional pitchers. Conversely, while proper lead knee extension improved ball velocity among high school pitchers, this did not minimize elbow varus torque. Clinical Relevance: Professional pitchers can extend their lead knee with minimal impact at the elbow. In high school pitchers, cognizance of proper full-body pitching mechanics remains a priority over increased velocity.

Idiopathic Subglottic Stenosis in Non-Caucasian Women.

Objective: To characterize presentation, disease course, and treatment of idiopathic subglottic stenosis (iSGS) in non-Caucasian women and compare this cohort to the predominantly female, Caucasian patient cohorts identified in the literature. Study Design: Retrospective review. Results are compared to systematic review of demographics. Setting: Multiple California institutions from 2008 to 2021. Methods: Patients with intubation within 2 years of disease or who met exclusion criteria listed in prior publications were excluded. A systematic review of iSGS patient demographics was also completed for comparison. Results: Of 421 patients with iSGS, 58 self-identified as non-Caucasian women, with 50 ultimately included. Mean age of onset was 45.1 years old (95% confidence interval [CI], 41.5-48.8), and mean age at diagnosis was 47.2 years (95% CI, 43.6-50.7). Mean Charlson comorbidity index was 1.06 (n = 49, 95% CI, 0.69-1.44). At diagnosis, Cotton-Meyer severity scores (documented in n = 45) were Cotton-Myer (CM) I (28.9%), CM II (40%), and CM III (31.1%). Mean age at first endoscopic surgery was 47.7 (95% CI, 44.2-51.3) years. 64% experienced disease recurrence with a median of 11 months between their first and second surgery. Our systematic review identified 60 studies that reported demographic features in patients with iSGS. 95% of pooled patients were Caucasian, while other demographic features were similar to the current cohort. Conclusion: The non-Caucasian population, almost 14% of this Californian cohort, does not differ from the majority Caucasian population detailed in contemporary literature. This cohort supports the presence of some racial and ethnic heterogeneity in this disease population.

Reliability and validity of belt-stabilized and tension dynamometry for assessing hip strength and power in uninjured adults.

OBJECTIVES: To investigate the intra-rater reliability and validity of belt-stabilized and tension dynamometry to assess hip muscle strength and power. DESIGN: Repeated measures. SETTING: Biomechanics laboratory. PARTICIPANTS: Seventeen uninjured adults (age = 22.0 ± 2.3y; 13 females). MAIN OUTCOMES MEASURES: Peak torque (strength) and rate of torque development (RTD; power) were measured for hip abduction, internal rotation, external rotation and extension using an isokinetic dynamometer, and belt-stabilized and tension dynamometry. RESULTS: For peak torque assessment, belt-stabilized and tension dynamometry showed good (Intraclass Correlation Coefficient [ICC] = 0.848-0.899) and good-to-excellent (ICC = 0.848-0.942) reliability, respectively. For RTD, belt-stabilized dynamometry showed fair reliability for abduction (ICC = 0.524) and good reliability for hip internal rotation, external rotation, and extension (ICC = 0.702-0.899). Tension dynamometry showed good reliability for all motions when measuring RTD (ICC = 0.737-0.897). Compared to isokinetic dynamometry, belt-stabilized and tension dynamometry showed good-to-excellent correlations for peak torque assessment (r = 0.503-0.870), and fair-to-good correlations for RTD (r = 0.438-0.674). Bland-Altman analysis showed that measures from belt-stabilized and tension dynamometry had clinically meaningful disagreement with isokinetic dynamometry. CONCLUSION: Tension dynamometry is reliable for assessing hip strength and power in all assessed motions. Belt-stabilized dynamometry is reliable for assessing internal rotation, external rotation, and extension. Validity of both methods is questionable, considering the lack of agreement with isokinetic dynamometry.

Clinical management of bone loss in cervical total disc arthroplasty: literature review and treatment recommendations.

PURPOSE: Cervical total disc replacement (cTDR) has been established as an alternative treatment for degenerative cervical radiculopathy and myelopathy. While the rate of complications for cTDR is reasonably low, recent studies have focused on bone loss after cTDR. The purpose of this work is to develop a clinical management plan for cTDR patients with evidence of bone loss. To guide our recommendations, we undertook a review of the literature and aimed to determine: (1) how bone loss was identified/imaged, (2) whether pre- or intraoperative assessments of infection or histology were performed, and (3) what decision-making and revision strategies were employed. METHODS: We performed a search of the literature according to PRISMA guidelines. Included studies reported the clinical performance of cTDR and identified instances of cervical bone loss. RESULTS: Eleven case studies and 20 cohort studies were reviewed, representing 2073 patients with 821 reported cases of bone loss. Bone loss was typically identified on radiographs during routine follow-up or by computed tomography (CT) for patients presenting with symptoms. Assessments of infection as well as histological and/or explant assessment were sporadically reported. Across all reviewed studies, multiple mechanisms of bone loss were suspected, and severity and progression varied greatly. Many patients were reportedly asymptomatic, but others experienced symptoms like progressive pain and paresthesia. CONCLUSION: Our findings demonstrate a critical gap in the literature regarding the optimal management of patients with bone loss following cTDR, and treatment recommendations based on our review are impractical given the limited amount and quality evidence available. However, based on the authors' extensive clinical experience, close follow-up of specific radiographic observations and serial radiographs to assess the progression/severity of bone loss and implant changes are recommended. CT findings can be used for clinical decision-making and further follow-up care. The pattern and rate of progression of bone loss, in concert with patient symptomatology, should determine whether non-operative or surgical intervention is indicated. Future studies involving implant retrieval, histopathological, and microbiological analysis for patients undergoing cTDR revision for bone loss are needed.

Preoperative factors predict prolonged length of stay, serious adverse complications, and readmission following operative intervention of proximal humerus fractures: a machine learning analysis of a national database.

Background: Proximal humerus fractures are a common injury, predominantly affecting older adults. This study aimed to develop risk-prediction models for prolonged length of hospital stay (LOS), serious adverse complications, and readmission within 30 days of surgically treated proximal humerus fractures using machine learning (ML) techniques. Methods: Adult patients (age >18) who underwent open reduction internal fixation (ORIF), hemiarthroplasty, or total shoulder arthroplasty for proximal humerus fracture between 2016 and 2021 were included. Preoperative demographic and clinical variables were collected for all patients and used to establish ML-based algorithms. The model with optimal performance was selected according to area under the curve (AUC) on the receiver operating curve (ROC) curve and overall accuracy, and the specific predictive features most important to model derivation were identified. Results: A total of 7473 patients were included (72.1% male, mean age 66.2 ± 13.7 years). Models produced via gradient boosting performed best for predicting prolonged LOS and complications. The model predicting prolonged LOS demonstrated good discrimination and performance, as indicated by (Mean: 0.700, SE: 0.017), recall (Mean: 0.551, SE: 0.017), accuracy (Mean: 0.717, SE: 0.010), F1-score (Mean: 0.616, SE: 0.014), AUC (Mean: 0.779, SE: 0.010), and Brier score (Mean: 0.283, SE: 0.010) Preoperative hematocrit, preoperative platelet count, and patient age were considered the strongest predictive features. The model predicting serious adverse complications exhibited comparable discrimination [precision (Mean: 0.226, SE: 0.024), recall (Mean: 0.697, SE: 0.048), accuracy (Mean: 0.811, SE: 0.010), F1-score (Mean: 0.341, SE: 0.031)] and superior performance relative to the LOS model [AUC (Mean: 0.806, SE: 0.024), Brier score (Mean: 0.189, SE: 0.010), noting preoperative hematocrit, operative time, and patient age to be most influential. However, the 30-day readmission model achieved the weakest relative performance, displaying low measures of precision (Mean: 0.070, SE: 0.012) and recall (Mean: 0.389, SE: 0.053), despite good accuracy (Mean: 0.791, SE: 0.009). Conclusion: Predictive models constructed using ML techniques demonstrated favorable discrimination and satisfactory-to-excellent performance in forecasting prolonged LOS and serious adverse complications occurring within 30 days of surgical intervention for proximal humerus fracture. Modifiable preoperative factors such as hematocrit and platelet count were identified as significant predictive features, suggesting that clinicians could address these factors during preoperative patient optimization to enhance outcomes. Overall, these findings highlight the potential for ML techniques to enhance preoperative management, facilitate shared decision-making, and enable more effective and personalized orthopedic care by exploring alternative approaches to risk stratification.

Test-Retest Reliability and Visual Perturbation Performance Costs During 2 Reactive Agility Tasks.

CONTEXT: High secondary injury rates after orthopedic surgeries have motivated concern toward the construct validity of return-to-sport test batteries, as it is evident that common strength and functional assessments fail to elicit pertinent behaviors like visual search and reactive decision making. This study aimed to establish the test-retest reliability of 2 reactive agility tasks and evaluate the impact of visual perturbation on physical performance. METHODS: Fourteen physically active individuals completed 2 agility tasks with reaction time (ie, 4 corner agility), working memory, and pathfinding (ie, color recall) components. Participants completed both tasks 4 times in 2 sessions scheduled 7 days apart. Outcomes included performance metrics of reaction time, time to target, number of targets, and total time assessed with reactive training timing gates. To assess test-retest reliability, we used intraclass correlation coefficients (ICCs), standard error of measurement (SEM), and minimal detectable change (MDC). Stroboscopic goggles induced visual perturbation during the fourth trial of each task. To assess the effect of visual perturbation, we used paired t tests and calculated performance costs. RESULTS: The 4-corner agility task demonstrated excellent reliability with respect to reaction time (ICC3,1 = .907, SEM = 0.13, MDC = 0.35 s); time to light (ICC3,1 = .935, SEM = 0.07, MDC = 0.18 s); and number of lights (ICC3,1 = .800, SEM = 0.24, MDC = 0.66 lights). The color recall task demonstrated good-to-excellent test-retest reliability for time to lights (ICC3,1 = .818-.953, SEM = 0.07-0.27, MDC = 0.19-0.74 s); test time (ICC3,1 = .969, SEM = 5.43, MDC = 15.04 s); and errors (ICC3,1 = .882, SEM = 0.19, MDC = 0.53 errors). Visual perturbation resulted in increased time to target (P = .022-.011), number of targets (P = .039), and total test time (P = .013) representing moderate magnitude degradation of performance (d = 0.55-0.87, performance costs = 5%-12%). CONCLUSIONS: Both tasks demonstrated acceptable test-retest reliability. Performance degraded on both tasks with the presence of visual perturbation. These results suggest standardized reactive agility tasks are reliable and could be developed as components of dynamic RTS testing.

Identification of ChatGPT-Generated Abstracts Within Shoulder and Elbow Surgery Poses a Challenge for Reviewers.

PURPOSE: To evaluate the extent to which experienced reviewers can accurately discern between AI-generated and original research abstracts published in the field of shoulder and elbow surgery and compare this to the performance of an AI-detection tool. METHODS: Twenty-five shoulder and elbow-related articles published in high-impact journals in 2023 were randomly selected. ChatGPT was prompted with only the abstract title to create an AI-generated version of each abstract. The resulting 50 abstracts were randomly distributed to and evaluated by 8 blinded peer reviewers with at least 5 years of experience. Reviewers were tasked with distinguishing between original and AI-generated text. A Likert scale assessed reviewer confidence for each interpretation and the primary reason guiding assessment of generated text was collected. AI output detector (0-100%) and plagiarism (0-100%) scores were evaluated using GPTZero. RESULTS: Reviewers correctly identified 62% of AI-generated abstracts and misclassified 38% of original abstracts as being AI-generated. GPTZero reported a significantly higher probability of AI output among generated abstracts (median 56%, IQR 51-77%) compared to original abstracts (median 10%, IQR 4-37%; p < 0.01). Generated abstracts scored significantly lower on the plagiarism detector (median 7%, IQR 5-14%) relative to original abstracts (median 82%, IQR 72-92%; p < 0.01). Correct identification of AI-generated abstracts was predominately attributed to the presence of unrealistic data/values. The primary reason for misidentifying original abstracts as AI was attributed to writing style. CONCLUSIONS: Experienced reviewers faced difficulties in distinguishing between human and AI-generated research content within shoulder and elbow surgery. The presence of unrealistic data facilitated correct identification of AI abstracts, whereas misidentification of original abstracts was often ascribed to writing style.

Publicly Available Anatomic Total Shoulder Arthroplasty Rehabilitation Protocols Show High Variability and Frequent Divergence from the 2020 ASSET Recommendations.

Background: In 2020, the American Society of Shoulder and Elbow Therapists (ASSET) published an evidence-based consensus statement outlining postoperative rehabilitation guidelines following anatomic total shoulder arthroplasty (TSA). Purpose: The purpose of this study was to (1) quantify the variability in online anatomic TSA rehabilitation protocols, and (2) assess their congruence with the ASSET consensus guidelines. Methods: This study was a cross-sectional investigation of publicly available, online rehabilitation protocols for anatomic TSA. A web-based search was conducted in April 2022 of publicly available rehabilitation protocols for TSA. Each collected protocol was independently reviewed by two authors to identify recommendations regarding immobilization, initiation, and progression of passive (PROM) and active range of motion (AROM), as well as the initiation and progression of strengthening and post-operative exercises and activities. The time to initiation of various components of rehabilitation was recorded as the time at which the activity or motion threshold was permitted by the protocol. Comparisons between ASSET start dates and mean start dates from included protocols were performed. Results: Of the 191 academic institutions included, 46 (24.08%) had publicly available protocols online, and a total of 91 unique protocols were included in the final analysis. There were large variations seen among included protocols for the duration and type of immobilization post-operatively, as well as for the initiation of early stretching, PROM, AROM, resistance exercises, and return to sport. Of the 37 recommendations reported by both the ASSET and included protocols, 31 (83.78%) were found to be significantly different between groups (p\<0.05). Conclusion: Considerable variability was found among online post-operative protocols for TSA with substantial deviation from the ASSET guidelines. These findings highlight the lack of standardization in rehabilitation protocols following anatomic TSA. Level of Evidence: 3b.

Early Fluid Is Less Fluid: Comparing Early Versus Late ICU Resuscitation in Severely Injured Trauma Patients.

OBJECTIVES: The temporal trends of crystalloid resuscitation in severely injured trauma patients after ICU admission are not well characterized. We hypothesized early crystalloid resuscitation was associated with less volume and better outcomes than delaying crystalloid. DESIGN: Retrospective, observational. SETTING: High-volume level 1 academic trauma center. PATIENTS: Adult trauma patients admitted to the ICU with emergency department serum lactate greater than or equal to 4 mmol/dL, elevated lactate (≥ 2 mmol/L) at ICU admission, and normal lactate by 48 hours. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: For the 333 subjects, we analyzed patient and injury characteristics and the first 48 hours of ICU course. Receipt of greater than or equal to 500 mL/hr of crystalloid in the first 6 hours of ICU admission was used to distinguish early vs. late resuscitation. Outcomes included ICU length of stay (LOS), ventilator days, and acute kidney injury (AKI). Unadjusted and multivariable regression methods were used to compare early resuscitation vs. late resuscitation. Compared with the early resuscitation group, the late resuscitation group received more volume by 48 hours (5.5 vs. 4.1 L; p ≤ 0.001), had longer ICU LOS (9 vs. 5 d; p ≤ 0.001), more ventilator days (5 vs. 2 d; p ≤ 0.001), and higher occurrence rate of AKI (38% vs. 11%; p ≤ 0.001). On multivariable regression, late resuscitation remained associated with longer ICU LOS and ventilator days and higher odds of AKI. CONCLUSIONS: Delaying resuscitation is associated with both higher volumes of crystalloid by 48 hours and worse outcomes compared with early resuscitation. Judicious crystalloid given early in ICU admission could improve outcomes in the severely injured.

A comparison of techniques to determine active motor threshold for transcranial magnetic stimulation research.

The determination of active motor threshold (AMT) is a critical step in transcranial magnetic stimulation (TMS) research. As AMT is frequently determined using an absolute electromyographic (EMG) threshold (e.g., 200 µV peak-to-peak amplitude), wide variation in EMG recordings across participants has given reason to consider relative thresholds (e.g., = 2 × background sEMG) for AMT determination. However, these approaches have not been systemically compared. Our purpose was to compare AMT estimations derived from absolute and relative criteria commonly used in the quadriceps, and assess the test-retest reliability of each approach. We used a repeated measures design to assess AMT estimations in the vastus lateralis (VL) from eighteen young adults (9 males and 9 females; mean ± SD age = 23 ± 2 years) across two laboratory visits. AMT was determined for each criterion, at each lab visit. A paired samples t-test was used to compare mean differences in AMT estimations during the second laboratory visit. Paired samples t-tests and intraclass correlation coefficients (ICC2,1) were calculated to assess test-retest reliability of each criterion. Differences between the criteria were small and not statistically significant (p = 0.309). The absolute criterion demonstrated moderate to excellent reliability (ICC2,1 = 0.866 [0.648-0.950]), but higher AMTs were observed in the second visit (p = 0.043). The relative criteria demonstrated good-to-excellent test-retest reliability (ICC2,1 = 0.894 [0.746-0.959]) and AMTs were not different between visits (p = 0.420). TMS researchers aiming to track corticospinal characteristics across visits should consider implementing relative criterion approaches during their AMT determination protocol.

Designing eco-evolutionary experiments for restoration projects: Opportunities and constraints revealed during stickleback introductions.

Eco-evolutionary experiments are typically conducted in semi-unnatural controlled settings, such as mesocosms; yet inferences about how evolution and ecology interact in the real world would surely benefit from experiments in natural uncontrolled settings. Opportunities for such experiments are rare but do arise in the context of restoration ecology-where different "types" of a given species can be introduced into different "replicate" locations. Designing such experiments requires wrestling with consequential questions. (Q1) Which specific "types" of a focal species should be introduced to the restoration location? (Q2) How many sources of each type should be used-and should they be mixed together? (Q3) Which specific source populations should be used? (Q4) Which type(s) or population(s) should be introduced into which restoration sites? We recently grappled with these questions when designing an eco-evolutionary experiment with threespine stickleback (Gasterosteus aculeatus) introduced into nine small lakes and ponds on the Kenai Peninsula in Alaska that required restoration. After considering the options at length, we decided to use benthic versus limnetic ecotypes (Q1) to create a mixed group of colonists from four source populations of each ecotype (Q2), where ecotypes were identified based on trophic morphology (Q3), and were then introduced into nine restoration lakes scaled by lake size (Q4). We hope that outlining the alternatives and resulting choices will make the rationales clear for future studies leveraging our experiment, while also proving useful for investigators considering similar experiments in the future.

How Fellowship Training Affects Complication Rate After Shoulder Arthroplasty: A Nationwide Assessment.

BACKGROUND: Total shoulder arthroplasty is performed by orthopedic surgeons with various fellowship training backgrounds. Whether surgeons performing shoulder arthroplasty with different types of fellowship training have differing rates of complications and reoperation remains unknown. METHODS: The PearlDiver Mariner database was retrospectively queried from the years 2010-2022. Patients undergoing shoulder arthroplasty were selected using the CPT code 23472. Those undergoing revision arthroplasty and those with a history of fracture, infection, or malignancy were excluded. Fellowship was determined and verified via online search. Only surgeons who performed a minimum of 10 cases were selected; and PearlDiver was queried using their provider ID codes. Primary outcome measures included 90-day, 1-year, and 5-year rates of complication and reoperation. A Bonferroni correction was utilized in which the significance threshold was set at p≤0.00023 RESULTS: In total, 150,385 patients met the inclusion criteria and were included in the study. Analysis of surgical trends revealed that Sports Medicine and Shoulder and Elbow fellowship- trained surgeons are performing an increasing percentage of all shoulder arthroplasty over time, with each cohort exhibiting am 11.3% and 4.2% increase from 2010 to 2022, respectively. The geographic region with the highest proportion of cases performed by Sports Medicine surgeons was the West, while the Northeast has the highest proportion of cases performed by Shoulder and Elbow surgeons. Shoulder and Elbow surgeons operated on patients that were significantly younger and had fewer comorbidities. Both Shoulder and Elbow and Sports Medicine surgeons had lower rates of postoperative complications at 90 days, 1 year and 5 years in comparison to surgeons who completed another type of fellowship or no fellowship. Across each time point, the rates of individual complications between Sports Medicine and Shoulder and Elbow were comparable, but the pooled complication rate was lowest in the Shoulder and Elbow cohort. CONCLUSION: Surgeons who have completed either a Sports Medicine or Shoulder and Elbow fellowship are performing an increasing proportion of shoulder arthroplasty over time. Sports Medicine and Shoulder and Elbow-trained surgeons have significantly lower complication rates at 90 days, 1 year and 5 years postoperatively. The individual complication rates between Sports Medicine and Shoulder and Elbow are comparable, but Shoulder and Elbow has the lowest pooled complication rates overall.

Electrochemical Imaging of Precisely-Defined Redox and Reactive Interfaces.

Understanding the diverse electrochemical reactions occurring at electrode-electrolyte interfaces (EEIs) is a critical challenge to developing more efficient energy conversion and storage technologies. Establishing a predictive molecular-level understanding of solid electrolyte interphases (SEIs) is challenging due to the presence of multiple intertwined chemical and electrochemical processes occurring at battery electrodes. Similarly, chemical conversions in reactive electrochemical systems are often influenced by the heterogeneous distribution of active sites, surface defects, and catalyst particle sizes. In this mini review, we highlight an emerging field of interfacial science that isolates the impact of specific chemical species by preparing precisely-defined EEIs and visualizing the reactivity of their individual components using single-entity characterization techniques. We highlight the broad applicability and versatility of these methods, along with current state-of-the-art instrumentation and future opportunities for these approaches to address key scientific challenges related to batteries, chemical separations, and fuel cells. We establish that controlled preparation of well-defined electrodes combined with single entity characterization will be crucial to filling key knowledge gaps and advancing the theories used to describe and predict chemical and physical processes occurring at EEIs and accelerating new materials discovery for energy applications.

Delays to Antibiotics in the Emergency Department and Risk of Mortality in Children With Sepsis.

Importance: Pediatric consensus guidelines recommend antibiotic administration within 1 hour for septic shock and within 3 hours for sepsis without shock. Limited studies exist identifying a specific time past which delays in antibiotic administration are associated with worse outcomes. Objective: To determine a time point for antibiotic administration that is associated with increased risk of mortality among pediatric patients with sepsis. Design, Setting, and Participants: This retrospective cohort study used data from 51 US children's hospitals in the Improving Pediatric Sepsis Outcomes collaborative. Participants included patients aged 29 days to less than 18 years with sepsis recognized within 1 hour of emergency department arrival, from January 1, 2017, through December 31, 2021. Piecewise regression was used to identify the inflection point for sepsis-attributable 3-day mortality, and logistic regression was used to evaluate odds of sepsis-attributable mortality after adjustment for potential confounders. Data analysis was performed from March 2022 to February 2024. Exposure: The number of minutes from emergency department arrival to antibiotic administration. Main Outcomes and Measures: The primary outcome was sepsis-attributable 3-day mortality. Sepsis-attributable 30-day mortality was a secondary outcome. Results: A total of 19 515 cases (median [IQR] age, 6 [2-12] years) were included. The median (IQR) time to antibiotic administration was 69 (47-116) minutes. The estimated time to antibiotic administration at which 3-day sepsis-attributable mortality increased was 330 minutes. Patients who received an antibiotic in less than 330 minutes (19 164 patients) had sepsis-attributable 3-day mortality of 0.5% (93 patients) and 30-day mortality of 0.9% (163 patients). Patients who received antibiotics at 330 minutes or later (351 patients) had 3-day sepsis-attributable mortality of 1.2% (4 patients), 30-day mortality of 2.0% (7 patients), and increased adjusted odds of mortality at both 3 days (odds ratio, 3.44; 95% CI, 1.20-9.93; P = .02) and 30 days (odds ratio, 3.63; 95% CI, 1.59-8.30; P = .002) compared with those who received antibiotics within 330 minutes. Conclusions and Relevance: In this cohort of pediatric patients with sepsis, 3-day and 30-day sepsis-attributable mortality increased with delays in antibiotic administration 330 minutes or longer from emergency department arrival. These findings are consistent with the literature demonstrating increased pediatric sepsis mortality associated with antibiotic administration delay. To guide the balance of appropriate resource allocation with time for adequate diagnostic evaluation, further research is needed into whether there are subpopulations, such as those with shock or bacteremia, that may benefit from earlier antibiotics.

Single Leg Hop Performance After Anterior Cruciate Ligament Reconstruction: Ready for Landing but Cleared for Take-Off?

CONTEXT: While the landing phases of the single-leg hop for distance (SLHD) are commonly assessed, limited work reflects how the take-off phase influences hop performance in patients with anterior cruciate ligament reconstruction (ACLR). OBJECTIVE: To compare trunk and lower extremity biomechanics between individuals with ACLR and matched uninjured controls during take-off of the SLHD. DESIGN: Cross-sectional study design. SETTING: Laboratory setting. PATIENTS OR OTHER PARTICIPANTS: 16 individuals with ACLR and 18 uninjured controls. MAIN OUTCOME MEASURES: Normalized quadriceps isokinetic torque, hop distance, and respective limb symmetry indices (LSI) were collected for each participant. Sagittal and frontal kinematics and kinetics of the trunk, hip, knee, and ankle, as well as vertical and horizontal ground reaction forces (GRF) were recorded for loading and propulsion of the take-off phase of the SLHD. RESULTS: Those with ACLR had weaker quadriceps peak torque in the involved limb (p=0.001) and greater strength asymmetry (p<0.001) compared to controls. Normalized hop distance was not statistically different between limbs or between groups (p>0.05) and hop distance symmetry was not different between groups (p>0.05). During loading, the involved limb demonstrated lesser knee flexion angles (p=0.030) and knee power (p=0.007) compared to the uninvolved limb, and lesser knee extension moments compared to the uninvolved limb (p=0.001) and controls (p=0.005). During propulsion, the involved limb demonstrated lesser knee extension moment (p=0.027), knee power (p=0.010), knee (p=0.032) and ankle work (p=0.032), anterior- posterior GRF (p=0.047), and greater knee (p=0.016) abduction excursions compared to the uninvolved limb. CONCLUSIONS: Between-limb differences in SLHD take-off suggest a knee underloading strategy in the involved limb. These results provide further evidence that distance covered during SLHD assessment can overestimate function and fail to identify compensatory biomechanical strategies.

A biomechanical study to optimize superior capsular reconstruction operative technique.

Background: The goals of this study were to optimize superior capsular reconstruction by assessing the relative fixation strength of 4 suture anchors; evaluating 3 glenoid neck locations for fixation strength and bone mineral density (BMD); determining if there is a correlation between BMD and fixation strength; and determining which portal sites have optimal access to the posterosuperior and anterosuperior glenoid neck for anchor placement. Methods: Twenty cadaveric specimens were randomized into 4 groups: all-suture anchor (FiberTak), conventional 3.0-mm knotless suture anchor (SutureTak), 3.9-mm knotless PEEK (polyetheretherketone) Corkscrew anchor, and 4.5-mm Bio-Corkscrew anchor. Each specimen was prepared with 3 anchors into the glenoid: an anterosuperior anchor, superior anchor, and posterosuperior anchor. All anchors were inserted into the superior glenoid neck 5 mm from the glenoid rim. A materials testing system performed cyclic testing (250 cycles) followed by load-to-failure testing at 12.5 mm/s. Cyclic elongation, first cycle excursion, maximum load, and stiffness were recorded. Using custom software, BMD was calculated at each anchor location. This software was also used to assess access to the posterosuperior and anterosuperior glenoid neck from standard arthroscopic portal positions. Results: There was no significant difference in cyclic elongation (P = .546), first cycle excursion (P = .476), maximum load (P = .817), or stiffness (P = .309) among glenoid anchor positions. Cyclic elongation was significantly longer in the PEEK Corkscrew group relative to the other implants (P ≤ .002). First cycle excursion was significantly greater in the FiberTak group relative to all other implants (P ≤ .008). For load-to-failure testing, the Bio-Corkscrew group achieved the highest maximum load (P ≤ .001). No other differences in cyclic or failure testing were observed between the groups. No differences in stiffness testing were observed (P = .133). The superior glenoid rim had the greatest BMD (P = .003), but there was no correlation between BMD and cyclic/load outcomes. The posterior portal (80% of specimens) and the anterior portal (60% of specimens) demonstrated the best access to the posterosuperior and anterosuperior glenoid neck, respectively. Conclusion: The 4.5-mm Bio-Corkscrew anchor provided the most robust fixation to the glenoid during superior capsular reconstruction as it demonstrated the strongest maximum load, had minimal elongation, had minimal first cycle excursion, and did not fail during cyclic testing. The superior glenoid neck had the highest BMD; however, there was no correlation between BMD or glenoid anchor location and biomechanical outcomes. The posterior portal and anterior portal provided optimal access to the posterosuperior glenoid neck and anterosuperior glenoid neck, respectively.