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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Posterior Shoulder Instability, Part I-Diagnosis, Nonoperative Management, and Labral Repair for Posterior Shoulder Instability-An International Expert Delphi Consensus Statement.

PURPOSE: To establish consensus statements on the diagnosis, nonoperative management, and labral repair for posterior shoulder instability. METHODS: A consensus process on the treatment of posterior shoulder instability was conducted, with 71 shoulder/sports surgeons from 12 countries participating on the basis of their level of expertise in the field. Experts were assigned to 1 of 6 working groups defined by specific subtopics within posterior shoulder instability. Consensus was defined as achieving 80% to 89% agreement, whereas strong consensus was defined as 90% to 99% agreement, and unanimous consensus was indicated by 100% agreement with a proposed statement. RESULTS: Unanimous agreement was reached on the indications for nonoperative management and labral repair, which include whether patients had primary or recurrent instability, with symptoms/functional limitations, and whether there was other underlying pathology, or patient's preference to avoid or delay surgery. In addition, there was unanimous agreement that recurrence rates can be diminished by attention to detail, appropriate indication and assessment of risk factors, recognition of abnormalities in glenohumeral morphology, careful capsulolabral debridement and reattachment, small anchors with inferior placement and multiple fixation points that create a bumper with the labrum, treatment of concomitant pathologies, and a well-defined rehabilitation protocol with strict postoperative immobilization. CONCLUSIONS: The study group achieved strong or unanimous consensus on 63% of statements related to the diagnosis, nonoperative treatment, and labrum repair for posterior shoulder instability. The statements that achieved unanimous consensus were the relative indications for nonoperative management, and the relative indications for labral repair, as well as the steps to minimize complications for labral repair. There was no consensus on whether an arthrogram is needed when performing advanced imaging, the role of corticosteroids/orthobiologics in nonoperative management, whether a posteroinferior portal is required. LEVEL OF EVIDENCE: Level V, expert opinion.

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.

Interpersonal Coordination between Female Soccer Players: Leader-Follower Roles within a Collision-Avoidance Task.

Background/Purpose: Return to sport decision-making may be improved by assessing an athlete's ability to coordinate movement with opponents in sport. The purpose was to investigate whether previous injuries associated with female soccer players' interpersonal coordination during a collision avoidance task. The authors hypothesized that external perturbations would disrupt the strength and stability of coordinated movement, and that individuals with a history of injury would be less likely to recover coordinated movement. Study Design: Cross-Sectional. Methods: Nine female athletes with a history of lower extremity injuries and nine without injuries were paired into dyads. Each dyad completed twenty trials of an externally paced collision-avoidance agility task with an unanticipated perturbation. Participant trajectories were digitized and analyzed using cross-recurrence quantification analysis (CRQA) to determine the strength and stability of interpersonal coordination dynamics. Trials in which participants with injury history assumed leader or follower roles within each dyad were then used to study how dyadic coordination varied across task stages (early, perturbation, and late) using linear mixed effect models. Cohen's d effect sizes were calculated to demonstrate magnitude of differences. In exploratory analysis, psychological readiness (i.e., self-reported knee functioning, fear of injury, and risk-taking propensity) was evaluated for their association with leader-follower status. Results: Perturbation disrupted the strength (R2=0.65, p<0.001, early=49.7±1.7, perturbation=41.1±1.7, d=0.39) and stability (R2=0.71, p < 0.001, early=65.0±1.6, perturbation=58.0±1.7, d=0.38) of interpersonal coordination regardless of leader-follower status. Individuals with injury history failed to restore coordination after the perturbation compared to control participants (injury=44.2.0±2.1, control=50.8±2.6, d=0.39). Neither demographic nor psychological measures were associated with leader-follower roles (B=0.039, p=0.224). Conclusion: Individuals with a history of lower extremity injury may have a diminished ability to adapt interpersonal coordination to perturbations, possibly contributing to a higher risk of re-injury. Level of Evidence: 3.

Posterior Shoulder Instability Part II - Glenoid Bone-Grafting, Glenoid Osteotomy, and Rehabilitation/Return to Play - An International Expert Delphi Consensus Statement.

PURPOSE: The purpose of this study was to establish consensus statements on glenoid bone-grafting, glenoid osteotomy, rehabilitation, return to play, and follow-up for posterior shoulder instability. METHODS: A consensus process on the treatment of posterior shoulder instability was conducted, with 71 shoulder/sports surgeons from 12 countries participating based on their level of expertise in the field. Experts were assigned to one of 6 working groups defined by specific subtopics within posterior shoulder instability. Consensus was defined as achieving 80-89% agreement, whereas strong consensus was defined as 90-99% agreement, and unanimous consensus was indicated by 100% agreement with a proposed statement. RESULTS: All of the statements relating to rehabilitation, return to play, and follow-up achieved consensus. There was unanimous consensus that the following criteria should be considered: restoration of strength, range of motion, proprioception, and sport-specific skills, with a lack of symptoms. There is no minimum time point required to return to play. Collision athletes and military athletes may take longer to return because of their higher risk for recurrent instability, and more caution should be exercised in clearing them to return to play, with elite athletes potentially having different considerations in returning to play. The relative indications for revision surgery are symptomatic apprehension, multiple recurrent instability episodes, further intra-articular pathologies, hardware failure, and pain. CONCLUSION: The study group achieved strong or unanimous consensus on 59% of statements. Unanimous consensus was reached regarding the criteria for return to play, collision/elite athletes having different considerations in return to play, indications for revision surgery, and imaging only required as routine for those with glenoid bone-grafting/osteotomies at subsequent follow-ups. There was no consensus on optimal fixation method for a glenoid bone-block, the relative indications for glenoid osteotomy, whether fluoroscopy is required or if the labrum should be concomitantly repaired. LEVEL OF EVIDENCE: Level V Expert Opinion.

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.

Presentation and management of infection in total disc replacement: A review.

Background: Total disc replacement (TDR) is widely used in the treatment of cervical and lumbar spine pathologies. Although TDR infection, particularly delayed infection, is uncommon, the results can be devastating, and consensus on clinical management remains elusive. In this review of the literature, we asked: (1) What are the reported rates of TDR infection; (2) What are the clinical characteristics of TDR infection; and (3) How has infection been managed for TDR patients? Methods: We performed a search of the literature using PubMed and Embase to identify studies that reported TDR infection rates, the identification and management of TDR infection, or TDR failures with positive cultures. Twenty database studies (17 focusing on the cervical spine and 3 on the lumbar spine) and 10 case reports representing 15 patients were reviewed along with device Summary of Safety and Effectiveness Data reports. Results: We found a lack of clarity regarding how infection was diagnosed, indicating a variation in clinical approach and highlighting the need for a standard definition of TDR infection. Furthermore, while reported infection rates were low, the absence of a clear definition prevented robust data analysis and may contribute to underreporting in the literature. We found that treatment strategy and success rely on several factors including patient symptoms and time to onset, microorganism type, and implant positioning/stability. Conclusions: Although treatment strategies varied throughout the extant literature, common practices in eliminating infection and reconstructing the spine emerged. The results will inform future work on the creation of a more robust definition of TDR infection and as well as recommendations for management.