Search

We report on the detailed characterization of the HD 77946 planetary system. HD 77946 is an F5 (M *  = 1.17 M⊙, R *  = 1.31 R⊙) star, which hosts a transiting planet recently discovered by NASA's Transiting Exoplanet Survey Satellite (TESS), classified as TOI-1778 b. Using TESS photometry, high-resolution spectroscopic data from HARPS-N, and photometry from CHEOPS , we measure the radius and mass from the transit and radial velocity observations, and find that the planet, HD 77946 b, orbits with period P b  =  |$6.527282_{-0.000020}^{+0.000015}$| d, has a mass of M b = 8.38 ± 1.32 M⊕, and a radius of |$R_{\rm b} = 2.705_{-0.081}^{+0.086}$| R⊕. From the combination of mass and radius measurements, and the stellar chemical composition, the planet properties suggest that HD 77946 b is a sub-Neptune with a ∼1  per cent H/He atmosphere. However, a degeneracy still exists between water-world and silicate/iron-hydrogen models, and even though interior structure modelling of this planet favours a sub-Neptune with a H/He layer that makes up a significant fraction of its radius, a water-world composition cannot be ruled out, as with |$T_{\rm eq}~= 1248^{+40}_{-38}~$| K, water may be in a supercritical state. The characterization of HD 77946 b, adding to the small sample of well-characterized sub-Neptunes, is an important step forwards on our journey to understanding planetary formation and evolution pathways. Furthermore, HD 77946 b has one of the highest transmission spectroscopic metrics for small planets orbiting hot stars, thus transmission spectroscopy of this key planet could prove vital for constraining the compositional confusion that currently surrounds small exoplanets. [ABSTRACT FROM AUTHOR]

Ninety eight newborn infants weighing less than 1500 g at birth and with gestational ages from 26 to 32 weeks were followed prospectively. They were grouped according to real time ultrasound scans in the neonatal period: infants in group A (n = 20) had periventricular haemorrhage (PVH) and normal ventricles; infants in group B (n = 26) had PVH and dilated ventricles (none with clinical hydrocephalus); and infants in group C, who formed the control group (n = 52), had no PVH and normal ventricles. At outpatient follow up a static image ultrasound scanner was used to measure the width of the lateral ventricles and brain hemispheres. The three groups of infants showed similar growth in occipitofrontal circumference, biparietal diameter, and brain hemispheres irrespective of a history of PVH or ventricular dilatation. The relation of ventricle size to biparietal diameter was similar in those infants in groups A (PVH alone) and C (controls) who had a good outcome. About a third (n = 8) of the infants in group B had persistent ventricular dilatation in relation to biparietal diameter and a poor outcome associated with developmental delay and cerebral palsy. By contrast, the remaining two thirds (n = 18) of the infants in group B who later had smaller ventricles in relation to biparietal diameter showed fewer neurodevelopmental sequelae. It is suggested that persistent ventricular dilatation in relation to biparietal diameter at follow up carries a bad prognosis, which might be due to brain atrophy. [ABSTRACT FROM AUTHOR]

Umbilical venous blood, and umbilical arterial blood pH, PO2, PCO2, and base excess were determined in 453 term infants at birth. The results indicate that umbilical venous blood pH, and umbilical arterial blood pH are significantly related to each another. Acidosis, as defined by an umbilical venous blood pH less than 7 X 27, is associated with a lower PO2, a raised PCO2, and a reduced buffer base when compared with PO2, PCO2, and buffer base associated with a normal pH (7 X 27-7 X 42), or alkalosis (pH greater than 7 X 42). The infant's condition at birth was recorded using modified Apgar scores, in which the gradings were vigorous (5-6), intermediate (3-4), or depressed (0-2). In the neonatal period, neurological abnormalities occurred in infants who had been in a depressed condition at birth in the presence of acidosis. Other infants, who had been in a depressed condition with a normal pH or alkalosis and the remaining infants who had an intermediate or a vigorous condition at birth, did not manifest neurological abnormalities in the neonatal period. Our findings suggest that measurement of umbilical venous blood pH, whose values correlate well with those of umbilical arterial blood pH, in infants who are in a depressed condition at birth improves the clinical assessment of the severity of asphyxia. [ABSTRACT FROM AUTHOR]

Objective:  The aim of the study was to compare the stiffness and cyclic fatigue of locking compression plate constructs from three manufacturers, DePuy Synthes (DPS), Knight Benedikt (KB), and Provet Veterinary Instrumentation (Vi), under cyclic torsion., Methods:  The constructs of DPS, KB, and Vi were assembled by fixing a 10-hole 3.5-mm stainless steel locking compression plate 1 mm away from a validated bone model with a fracture gap of 47 mm. The corresponding drill guides and locking screws were used. Three groups of six constructs were tested in cyclic torsion until failure., Results:  There was no significant difference in initial stiffness between DPS constructs (28.83 ± 0.84 N·m/rad) and KB constructs (28.38 ± 0.81 N·m/rad), and between KB constructs and Vi constructs (27.48 ± 0.37 N·m/rad), but the DPS constructs were significantly stiffer than the Vi constructs. The DPS constructs sustained the significantly highest number of cycles (24,833 ± 2,317 cycles) compared with KB constructs (16,167 ± 1,472 cycles) and Vi constructs (19,833 ± 4,792 cycles), but the difference between KB and Vi constructs was not significant. All constructs failed by screw damage at the shaft between the plate and the bone model., Conclusion:  DPS constructs showed superior initial torsional stiffness and cyclic fatigue life than Vi constructs, whereas KB and Vi constructs shared comparable results. Further investigation is required to assess the clinical significance of these biomechanical differences., Competing Interests: D.R.J. is an occasional presenter and consultant on the products of Knight Benedikt. None of the other authors have any conflicts of interest to declare., (Thieme. All rights reserved.)

Background: Persons of low socioeconomic status are overrepresented in the firearm injury patient population and may experience challenges in accessing complex outpatient health systems. Consequently, outpatient care for these patients is plagued by poor follow-up and increased emergency department (ED) utilization. We developed a Post Discharge Care Team (PDCT) consisting of a dedicated trauma nurse navigator and medical social worker to bridge the gap between hospital discharge and outpatient care to improve recovery., Methods: Adult firearm injury survivors admitted to the trauma service were randomized 1:1 to receive either PDCT services or standard of care (SOC) workflows. The PDCT nurse provided education and set expectations regarding injuries, wound care, and outpatient follow-up. The PDCT social worker performed a comprehensive assessment to identify concerns including housing and financial instability, food insecurity, or transportation issues. The primary outcome was ED utilization, with secondary outcomes including readmissions and overall health care costs compared between groups., Results: In the first 6 months of the study, a total of 44 patients were randomized to PDCT and 47 to SOC. There were 10 patients who visited the ED in the PDCT group compared with 16 in the SOC group ( p = 0.23) for a total of 14 and 23 ED visits, respectively. There were 14 patients in the PDCT and 11 patients in the SOC groups who were readmitted ( p = 0.31), but the PDCT group was readmitted for 27.9 fewer hospital days. After accounting for programmatic costs, the PDCT had a hospital savings of $34,542.71., Conclusion: A collaborative, specialized PDCT for firearm injury survivors consisting of a dedicated trauma nurse navigator and medical social worker decreased outpatient ED utilization, readmission days, and was cost effective. Trauma centers with high volumes of penetrating trauma should consider a similar model to improve outpatient care for firearm injury survivors., Level of Evidence: Therapeutic/Care Management; Level III., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Association for the Surgery of Trauma.)

Background: Isolated ACL reconstructions (ACLR) demonstrate limitations in restoring native knee kinematics. This study investigates the knee mechanics of ACLR plus various anterolateral augmentations using a patient-specific musculoskeletal knee model., Materials and Methods: A patient-specific knee model was developed in OpenSim using contact surfaces and ligament details derived from MRI and CT data. The contact geometry and ligament parameters were varied until the predicted knee angles for intact and ACL-sectioned models were validated against cadaveric test data for that same specimen. Musculoskeletal models of the ACLR combined with various anterolateral augmentations were then simulated. Knee angles were compared between these reconstruction models to determine which technique best matched the intact kinematics. Also, ligament strains calculated by the validated knee model were compared to those of the OpenSim model driven by experimental data. The accuracy of the results was assessed by calculating the normalised RMS error (NRMSE); an NRMSE < 30% was considered acceptable., Results: All rotations and translations predicted by the knee model were acceptable when compared to the cadaveric data (NRMSE < 30%), except for the anterior/posterior translation (NRMSE > 60%). Similar errors were observed between ACL strain results (NRMSE > 60%). Other ligament comparisons were acceptable. All ACLR plus anterolateral augmentation models restored kinematics toward the intact state, with ACLR plus anterolateral ligament reconstruction (ACLR + ALLR) achieving the best match and the greatest strain reduction in ACL, PCL, MCL, and DMCL., Conclusion: The intact and ACL-sectioned models were validated against cadaveric experimental results for all rotations. It is acknowledged that the validation criteria are very lenient; further refinement is required for improved validation. The results indicate that anterolateral augmentation moves the kinematics closer to the intact knee state; combined ACLR and ALLR provide the best outcome for this specimen., (© 2023. The Author(s).)

Purpose: The impact of the social determinants of health (SDOH) on hospitalized cancer patients and hospital length of stay is unknown. At our institution, a hospital-wide SDOH survey that examined patient-specific barriers to various domains of SDOH and facilitated hospital discharge was integrated into the electronic medical record. This study reports the effect of the SDOH survey on length of stay for oncology patients and the outpatient referrals generated to facilitate the discharge., Methods: We examined length of stay index data on inpatient oncology patients and 2 comparator services (bone marrow transplant, internal medicine). We evaluated the length of stay using a 2-sample t test, and the rate of referrals per discharge using a 2-sample Poisson test., Results: Compared to the baseline length of stay, after the launch of the SDOH survey, there was a significant (8.9%) decrease in the average length of stay for oncology patients (8.14 to 7.41 days, P  = 0.004), the LOS decrease for the bone marrow transplant and subset was a nonsignificant trend only ( P  > 0.1). Average referrals per discharge increased from baseline 1.063 per discharge to 1.159 after implementation ( P  = 0.004), and the mean values increased by 9%., Conclusions: The SDOH survey tool assisted in a timely examination of patient-specific barriers to discharge, leveraged care coordination, and facilitated a safe hospital discharge. Such efforts increase the efficiency of health care service delivery in response to public health threats, such as the COVID-19 pandemic., (Copyright© Board of Regents of the University of Wisconsin System and The Medical College of Wisconsin, Inc.)

Background: The practice of cement augmentation in pedicle screw fixation is well established. However, there is a lack of consensus regarding the optimal screw design or cement type. This remains a clinically important question given the incidence of cement augmentation-associated complications. While fenestrated screws have become widely used in clinical practice, the relationship between fenestration placement along the screw axis and cement plume geometry and pullout strength have yet to be clarified. This study was designed to evaluate the mechanical and geometric properties of different fenestrated screw designs and cement viscosities in pedicle screw fixation., Methods: Three different screw fenestration configurations and 2 different cement viscosities were examined in this study. Axial pullout tests were conducted in both foam blocks and cadaveric vertebrae. All vertebral specimens underwent tests of bone mineral density. In the foam blocks, 6 tests were conducted for each augmentation combination and also for nonaugmented controls. In the cadaveric testing, 36 lumbar vertebrae were instrumented with a cemented and uncemented control screw to compare features of fixation. Computed tomography (CT) images were taken to assess the geometric profile of the cement plumes in both the foam blocks and the cadaveric vertebrae., Results: In both foam blocks and vertebral specimens, cementation was shown to confer a significant increase in pullout strength. Significant correlations existed between the anterior-posterior and lateral cement plume diameters and pullout strength in cadaveric vertebra and foam blocks, respectively. Within instrumented vertebra, variables such as the width of the vertebral body and screw insertion were found to significantly correlate with enhanced fixation. CT analysis of the instrumented vertebra demonstrated that a centrally distributed pattern of fenestrations was found to result in a cement plume with consistently predictable distribution within the vertebral body, without evidence of leak., Conclusion: Cementation of fenestrated pedicle screws increases overall pullout forces; however, there is an unclear relationship between the geometric properties of the cement plume and the overall strength of the screw-bone interface. This study demonstrates that the plume diameter, vertebral body width, and angle of screw insertion are correlated with enhanced pullout strength. Furthermore, varying the fenestration design of injectable screws resulted in a set of predictable plume patterns, which may be associated with fewer complications. Further investigation is required to clarify the optimal geometric and biomechanical properties of injectable pedicle screws and their role in establishing the cement-bone interface., Clinical Relevance: This study is relevant to currently practicing spinal surgeons and biomechanical engineers., Competing Interests: Declaration of Conflicting Interests: The authors report no conflicts of interest in this work., (This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery. Copyright © 2022 ISASS. To see more or order reprints or permissions, see http://ijssurgery.com.)

Objective: To examine the efficacy of weight-adjusted D-cycloserine (DCS) (35 or 70 mg) relative to placebo augmentation of intensive exposure therapy for youth with obsessive-compulsive disorder (OCD) in a double-blind, randomised controlled trial, and examine whether antidepressant medication or patient age moderated outcomes., Methods: Youth (n = 100, 7-17 years) with OCD were randomised in a 1:1 ratio to either DCS + exposure (n = 49) or placebo + exposure (n = 51). Assessments occurred posttreatment, 1 month later, and at 3 and 6 months. Pills were ingested immediately before sessions., Results: Significant improvements on all outcomes were observed at posttreatment, and to 6-month follow-up. Treatment arms did not differ across time, with no significant time-by-medication interactions on symptom severity (T1 to T2 estimate: 9.3, 95% confidence interval [CI]: -11.2 to -7.4, and estimate -10.7, 95% CI: -12.6 to -8.7), diagnostic severity (T1 to T2 estimate: -2.0, 95% CI: -2.4 to -1.5 and estimate -2.5, 95% CI: -3.0 to -2.0) or global functioning (T1 to T2 estimate: 13.8, 95% CI: 10.6 to 17.0, and estimate 16.6, 95% CI: 13.2 to 19.9). Neither antidepressants at baseline nor age moderated primary outcomes. There were significantly fewer responders/remitters at 1- and 6-month follow-up among youth in the DCS condition stabilised on SSRIs, relative to youth not taking SSRIs., Conclusions: DCS augmented intensive exposure therapy did not result in overall additional benefits relative to placebo. Intensive exposure proved effective in reducing symptoms for the overall sample., (© 2022 The Authors. Depression and Anxiety published by Wiley Periodicals LLC.)

Background: The ligaments in the knee are prone to injury especially during dynamic activities. The resulting instability can have a profound impact on a patient's daily activities and functional capacity. Musculoskeletal knee modelling provides a non-invasive tool for investigating ligament force-strain behaviour in various dynamic scenarios, as well as potentially complementing existing pre-planning tools to optimise surgical reconstructions. However, despite the development and validation of many musculoskeletal knee models, the effect of modelling parameters on ligament mechanics has not yet been systematically reviewed., Objectives: This systematic review aimed to investigate the results of the most recent studies using musculoskeletal modelling techniques to create models of the native knee joint, focusing on ligament mechanics and modelling parameters in various simulated movements., Data Sources: PubMed, ScienceDirect, Google Scholar, and IEEE Xplore., Eligibility Criteria for Selecting Studies: Databases were searched for articles containing any numerical ligament strain or force data on the intact, ACL-deficient, PCL-deficient, or lateral extra-articular reconstructed (LER) knee joints. The studies had to derive these results from musculoskeletal modelling methods. The dates of the publications were between 1 January 1995 and 30 November 2021., Method: A customised data extraction form was created to extract each selected study's critical musculoskeletal model development parameters. Specific parameters of the musculoskeletal knee model development used in each eligible study were independently extracted, including the (1) musculoskeletal model definition (i.e., software used for modelling, knee type, source of geometry, the inclusion of cartilage and menisci, and articulating joints and joint boundary conditions (i.e., number of degrees of freedom (DoF), subjects, type of activity, collected data and type of simulation)), (2) specifically ligaments modelling techniques (i.e., ligament bundles, attachment points, pathway, wrapping surfaces and ligament material properties such as stiffness and reference length), (3) sensitivity analysis, (4) validation approaches, (5) predicted ligament mechanics (i.e., force, length or strain) and (6) clinical applications if available. The eligible papers were then discussed quantitatively and qualitatively with respect to the above parameters., Results and Discussion: From the 1004 articles retrieved by the initial electronic search, only 25 met all inclusion criteria. The results obtained by aggregating data reported in the eligible studies indicate that considerable variability in the predicted ligament mechanics is caused by differences in geometry, boundary conditions and ligament modelling parameters., Conclusion: This systematic review revealed that there is currently a lack of consensus on knee ligament mechanics. Despite this lack of consensus, some papers highlight the potential of developing translational tools using musculoskeletal modelling. Greater consistency in model design, incorporation of sensitivity assessment of the model outcomes and more rigorous validation methods should lead to better agreement in predictions for ligament mechanics between studies. The resulting confidence in the musculoskeletal model outputs may lead to the development of clinical tools that could be used for patient-specific treatments., Competing Interests: The authors have declared that no competing interests exist.

Objectives: To compare global warming potential (GWP) of hospitals converting from single-use sharps containers to reusable sharps containers (SSC, RSC). Does conversion to RSC result in GWP reduction?, Design: Using BS PAS 2050:2011 principles, a retrospective, before/after intervention quantitative model together with a purpose-designed, attributional 'cradle-to-grave' life-cycle tool, were used to determine the annual greenhouse gas (GHG) emissions of the two sharps containment systems. Functional unit was total fill line litres (FLL) of sharps containers needed to dispose of sharps for 1-year period in 40 trusts. Scopes 1, 2 and 3 emissions were included. Results were workload-normalised using National Health Service (NHS) national hospital patient-workload indicators. A sensitivity analysis examined areas of data variability., Setting: Acute care hospital trusts in UK., Participants: 40 NHS hospital Trusts using RSC., Intervention: Conversion from SSC to RSC. SSC and RSC usage details in 17 base line trusts immediately prior to 2018 were applied to the RSC usage details of the 40 trusts using RSC in 2019., Primary Outcome Measure: The comparison of GWP calculated in carbon dioxide equivalents (CO 2 e) generated in the manufacture, transport, service and disposal of 12 months, hospital-wide usage of both containment systems in the 40 trusts., Results: The 40 trusts converting to RSC reduced their combined annual GWP by 3267.4 tonnes CO 2 e (-83.9%); eliminated incineration of 900.8 tonnes of plastic; eliminated disposal/recycling of 132.5 tonnes of cardboard and reduced container exchanges by 61.1%. GHG as kg CO 2 e/1000 FLL were 313.0 and 50.7 for SSC and RSC systems, respectively. A sensitivity analysis showed substantial GHG reductions within unit processes could be achieved, however, their impact on relevant final GWP comparison varied <5% from base comparison., Conclusions: Adopting RSC is an example of a sustainable purchasing decision that can assist trusts meet NHS GHG reduction targets and can reduce GWP permanently with minimal staff behavioural change., Competing Interests: Competing interests: TRG is an international consultant on sharps injury prevention and sharps containment to healthcare facilities, professional associations and contractors in the healthcare sector, and from time to time, Sharpsmart UK (the manufacturer of the RSC studied in this paper) use his services. All other authors are employed by, or associated with, trusts using Sharpsmart reusable sharps containers and declare no conflicts of interest., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Meniscus root repairs are important for restoring knee function after a complete meniscus root tear. Various suturing patterns have been proposed for the root repair. The 2-simple-stitches (TSS) method is currently the preferred technique, as it is simplest to perform and allows the least displacement of the meniscus root., Purpose: To compare the biomechanical properties of a posterior medial meniscus transtibial root repair consisting of an all-inside meniscal repair device (AMRD) construct with the TSS pullout suture pattern., Study Design: Controlled laboratory study., Methods: Ten pairs of cadaveric medial menisci were prepared with 1 of the 2 constructs. The constructs were randomized between pairs. All constructs were subjected to preloading with 2 N for 10 seconds and then cyclic loading from 5 N to 20 N for 1000 cycles at a frequency of 0.5 Hz. Subsequently, the menisci were loaded to failure at a rate of 0.5 mm/s. All loads were applied in-line with the circumferential meniscal fibers near the posterior medial meniscal horn., Results: The mean yield load and stiffness were similar for both constructs. The elongation after cyclic loading was greater for the AMRD. The displacement at both yield load and ultimate failure were also higher for the AMRD. The ultimate failure load of the AMRD was also significantly higher. During load to failure, the mode of failure in the AMRD was heterogeneous. All the TSS constructs failed by suture cutout., Conclusion: Posterior medial meniscus root repairs using both the AMRD and TSS constructs have elongation under the biomechanically acceptable threshold of 3 mm. The stiffness and yield loads indicate similar mechanical properties of the constructs. However, the significantly higher elongation for the AMRD leaves the TSS method as the preferred option for transtibial repairs. Despite this, the AMRD construct may still represent a viable alternative to the TSS suture pattern, comparable to alternative suture patterns with similar limitations., Clinical Relevance: The AMRD construct may represent a viable alternative to the TSS suture pattern., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: Smith & Nephew provided the funding for this study as well as donating the devices and sutures. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2021.)

Objective: The optimal anterolateral procedure to control anterolateral rotational laxity of the knee is still unknown. The objective was to compare the ability of five anterolateral procedures performed in combination with anterior cruciate ligament reconstruction (ACLR) to restore native knee kinematics in the setting of a deficient anterior cruciate ligament (ACL) and anterolateral structures., Methods: A controlled laboratory study was performed using 10 fresh-frozen cadaveric whole lower limbs with intact iliotibial band. Kinematics from 0° to 90° of flexion were recorded using a motion analysis three-dimensional (3D) optoelectronic system, allowing assessment of internal rotation (IR) and anteroposterior (AP) tibial translation at 30° and 90° of flexion. Joint centres and bony landmarks were calculated from 3D bone models obtained from CT scans. Intact knee kinematics were assessed initially, followed by sequential section of the ACL and anterolateral structures (anterolateral ligament, anterolateral capsule and Kaplan fibres). After ACLR, five anterolateral procedures were performed consecutively on the same knee: ALLR, modified Ellison, deep Lemaire, superficial Lemaire and modified MacIntosh. The last three procedures were randomised. For each procedure, the graft was fixed in neutral rotation at 30° of flexion and with a tension of 20 N., Results: Isolated ACLR did not restore normal overall knee kinematics in a combined ACL plus anterolateral-deficient knee, leaving a residual tibial rotational laxity (p=0.034). Only the ALLR (p=0.661) and modified Ellison procedure (p=0.641) restored overall IR kinematics to the normal intact state. Superficial and deep Lemaire and modified MacIntosh tenodeses overconstrained IR, leading to shifted and different kinematics compared with the intact condition (p=0.004, p=0.001 and p=0.045, respectively). Compared with ACLR state, addition of an anterolateral procedure did not induce any additional control on AP translation at 30° and 90° of flexion (all p>0.05), except for the superficial Lemaire procedure at 90° (p=0.032)., Conclusion: In biomechanical in vitro setting, a comparison of five anterolateral procedures revealed that addition of either ALLR or modified Ellison procedure restored overall native knee kinematics in a combined ACL plus anterolateral-deficient knee. Superficial and deep Lemaire and modified MacIntosh tenodeses achieved excellent rotational control but overconstrained IR, leading to a change from intact knee kinematics., Level of Evidence: The level-of-evidence statement does not apply for this laboratory experiments study., Competing Interests: Competing interests: None declared., (© International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: Given the common occurrence of residual laxity and re-injury post anterior cruciate ligament reconstruction (ACLR), additional anterolateral procedures are increasingly used in combination with an ACLR. Despite the perception that there is a risk of over-constraining the lateral tibiofemoral (LTF) compartment, potentially leading to osteoarthritis, assessment on their effect on intra-articular compartment pressures is still lacking. Our objective was therefore, through a pilot biomechanical study, to compare LTF contact pressures after the most commonly used anterolateral procedures., Methods: A controlled laboratory pilot study was performed using 4 fresh-frozen cadaveric whole lower limbs. Through 0° to 90° of flexion, LTF contact pressures were measured with a Tekscan sensor, located under the lateral meniscus. Knee kinematics were obtained in 3 conditions of rotation (NR: neutral, ER: external and IR: internal rotation) to record the position of the knees for each loading condition. A Motion Analysis system with a coordinate system based on CT scans 3D bone modelling was used. After an ACLR, defined as the reference baseline, 5 anterolateral procedures were compared: anterolateral ligament reconstruction (ALLR), modified Ellison, deep Lemaire, superficial Lemaire and modified MacIntosh procedures. The last 3 procedures were randomised. For each procedure, the graft was fixed in NR at 30° of flexion and with a tension of 20 N., Results: Compared with isolated ACLR, addition of either ALLR or modified Ellison procedure did not increased the overall LTF contact pressure (all p>0.05) through the full range of flexion for the IR condition. Conversely, deep Lemaire, superficial Lemaire and modified MacIntosh procedure (all p<0.05) did increase the overall LTF contact pressure compared with ACLR in IR. No significant difference was observed in ER and NR conditions., Conclusion: This pilot study, comparing the main anterolateral procedures, revealed that addition of either ALLR or modified Ellison procedure did not change the overall contact pressure in the LTF compartment through 0° to 90° of knee flexion. In contrast, the deep and superficial Lemaire, and modified MacIntosh procedures significantly increased overall LTF contact pressures when the knee was internally rotated., Competing Interests: Competing interests: None declared., (© International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Suture pullout during rehabilitation may result in loss of tension in the inferior glenohumeral ligament (IGHL) and contribute to recurrent instability after capsular plication, performed with or without labral repair. To date, the suture pullout strength in the IGHL is not well-documented. This may contribute to recurrent instability., Purpose/hypothesis: A cadaveric biomechanical study was designed to investigate the suture pullout strength of sutures in the IGHL. We hypothesized that there would be no significant variability of suture pullout strength between specimens and zones. Additionally, we sought to determine the impact of early mobilization on sutures in the IGHL at time zero. We hypothesized that capsular plication sutures would fail under low load., Study Design: Descriptive laboratory study., Methods: Seven fresh-frozen cadaveric shoulders were dissected to isolate the IGHL complex, which was then divided into 18 zones. Sutures in these zones were attached to a linear actuator, and the resistance to suture pullout was recorded. A suture pullout strength map of the IGHL was constructed. These loads were used to calculate the load applied at the hand that would initiate suture pullout in the IGHL., Results: Mean suture pullout strength for all specimens was 61.6 ± 26.1 N. The maximum load found to cause suture pullout through tissue was found to be low, regardless of zone of the IGHL. Calculations suggest that an external rotation force applied to the hand of only 9.6 N may be sufficient to tear capsular sutures at time zero., Conclusion: This study did not provide clear evidence of desirable locations for fixation in the IGHL. However, given the low magnitude of failure loads, the results suggest the timetable for initiation of range-of-motion exercises should be reconsidered to prevent suture pullout through the IGHL., Clinical Relevance: From this biomechanical study, the magnitude of force required to cause suture pullout through the IGHL is met or surpassed by normal postoperative early range-of-motion protocols., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: S.R. has received research support from Mathys Orthopaedics. D.B. has received research support from Smith & Nephew; consulting fees and speaking fees from Mathys Orthopaedics, Rotation Medical, Smith & Nephew, Wright Medical, and Zimmer Biomet; and royalties from Allegra Orthopaedics; and has stock/stock options in Allegra Orthopaedics. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2021.)

Background: Patellar tendinopathy is an overuse condition affecting athletes, often with a high morbidity if left untreated. High-level evidence fails to support the use of surgery. A tibial tubercle osteotomy (TTO) has been suggested as a surgical option to improve patient outcomes. Our aim was to explore whether a distalising TTO will alter the patellar tendon to quadriceps tendon force ratio and the sagittal patellar tilt., Methods: Six cadaver limbs were placed in a custom jig with a mechanical testing machine applying cyclical loads of 200-500 N to the quadriceps tendon. The knee was fixed at 0, 15, 30, 45, 60, 75 and 90° of flexion and a buckle transducer recorded the resultant patellar tendon force. Testing was performed with the native tibial tubercle position and with the tubercle distalised by 11 mm. Testing was also performed with the tubercle anteriorised by 10 mm at both of these tubercle positions, a total of four different testing positions., Results: There was a significant decrease in the patellar tendon to quadriceps tendon force ratio from 30-60° of knee flexion. There was a significant increase in the sagittal patellar tilt at 30° of knee flexion with distalisation., Conclusion: This biomechanical study shows that the patellar tendon to quadriceps tendon force ratio can be altered with a distalising tibial tubercle osteotomy. A tibial tubercle osteotomy may be a biomechanical treatment option for recalcitrant patellar tendinopathy by decreasing the load through the patellar tendon, allowing the athlete to maintain higher training volumes and loads., (Copyright © 2020. Published by Elsevier B.V.)

Background: To assess whether lumbar pedicle screw placement with a minimally invasive surgical (MIS) vs. open technique imparts different biomechanical parameters and thus may affect failure rates., Methods: Human cadaveric disarticulated lumbar vertebrae 1-5 were stabilised in cement. Pedicle screws were inserted either via the 'MIS' or 'open' technique, based on previously described anatomical landmarks. Each vertebra had one 'MIS' and one 'open' technique screw. Specimens were tested with an Instron mechanical testing machine, positioned to allow for testing of direct coaxial force. Load was applied until failure occurred, and load-displacement curves generated for each screw., Results: Average failure load was found to be 685±399 N for MIS, versus 661±323 N for open technique (P=0.75). The average ultimate failure load was 748±421 N for MIS, versus 772±326 N for open (P=0.74). Average displacement until failure was 0.95±0.49 mm for MIS as compared to 0.95±0.62 mm for open (P=0.996). Axial stiffness was 936±217 N/mm for MIS and 1,016±263 N/mm for open (P=0.19). Average work required to result in failure was 0.84±1.09 J for MIS and 0.82±1.05 J for open (P=0.94)., Conclusions: There was no significant difference in the biomechanical properties of the MIS as compared with open lumbar pedicle screws, when tested until failure under direct coaxial force. The clinical implication may be that there is no significant advantage in the biomechanical properties of MIS versus open lumbar pedicle screw insertion techniques., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare., (2020 Journal of Spine Surgery. All rights reserved.)

Background: In anterior cruciate ligament reconstruction, quadrupled semitendinosus (Quad ST) grafts have potential advantages over doubled semitendinosus-gracilis (ST/G) including larger diameter and gracilis preservation, however the ideal tibial fixation method of the resultant shorter Quad ST graft remains elusive if a fixed-loop suspensory fixation device is used on the femur. We investigated whether the tibial fixation biomechanical properties of a Quad ST fixed indirectly with polyethylene terephthalate tape tied over a screw in a full outside-in created tunnel was superior to a ST/G graft fixed with an interference screw., Materials and Methods: In a controlled laboratory study, six cadaveric matched pairs of each construct were subjected to cyclic loading to mimic physiologic loading during rehabilitation. This included preconditioning cycling, cyclic loading to 220 N for 500 cycles, then cyclic loading to 500 N for 500 cycles., Results: High standard deviations across the measured parameters occurred with no significant difference between measured parameters of elongation for the different constructs. Elongation of the Quad-ST construct was greater at 10 and 100 cycles, but not statistically different. Four of the six Quad-ST constructs failed below 100 cycles, compared with two failures below 100 cycles in the ST/G construct. There was a strong correlation between cycles to failure and bone mineral density for the Quad ST-tape constructs., Conclusions: Tibial fixation of Quad ST with a tied tape-screw construct in a full-length tunnel was not biomechanically superior to ST/G graft fixed with an interference screw, exhibited greater nonsignificant construct elongation with earlier failure, and was more reliant on bone mineral density., Level of Evidence: In vitro laboratory study.

Emerging evidence suggests that cognitive-behavioral therapy (CBT) is an efficacious treatment for adolescent body dysmorphic disorder (BDD) in the short term, but longer-term outcomes remain unknown. The current study aimed to follow up a group of adolescents who had originally participated in a randomized controlled trial of CBT for BDD to determine whether treatment gains were maintained. Twenty-six adolescents (mean age = 16.2, SD = 1.6) with a primary diagnosis of BDD received a course of developmentally tailored CBT and were followed up over 12 months. Participants were assessed at baseline, midtreatment, posttreatment, 2-, 6-, and 12-month follow-up. The primary outcome measure was the clinician-rated Yale-Brown Obsessive-Compulsive Scale Modified for BDD. Secondary outcomes included measures of insight, depression, quality of life, and global functioning. BDD symptoms decreased significantly from pre- to posttreatment and remained stable over the 12-month follow-up. At this time point, 50% of participants were classified as responders and 23% as remitters. Participants remained significantly improved on all secondary outcomes at 12-month follow-up. Neither baseline insight nor baseline depression predicted long-term outcomes. The positive effects of CBT appear to be durable up to 12-month follow-up. However, the majority of patients remained symptomatic and vulnerable to a range of risks at 12-month follow-up, indicating that longer-term monitoring is advisable in this population. Future research should focus on enhancing the efficacy of CBT in order to improve long-term outcomes., (Copyright © 2017. Published by Elsevier Ltd.)

Adolescence is a critical time for physical development and maturation, and with these important physiological changes comes greater awareness of body image and appearance, which, for a proportion of young people can become excessive, signaling the onset of body dysmorphic disorder (BDD). BDD in adolescence is associated with significant impairment and suicidality, is poorly understood, and currently there is limited evidence for the effectiveness of psychological therapy. Cognitive behavioral therapy (CBT) is currently the most promising and best available psychological therapy for BDD in youth. The aim of this article is to provide clinicians with information on CBT treatment for BDD in young people and to provide guidance based on clinical experience of working with this complex population group. The article will include discussion of strategies including maximizing psychoeducation with parental involvement, the use of cognitive therapy techniques, exposure with response prevention, and perceptual visual training techniques, including attention training and mirror retraining.

Obsessive-compulsive disorder (OCD) is a debilitating mental health disorder, occurring in 1-2% of children and adolescents. Current evidence-based treatments produce promising rates of remission; however, many children and youth do not fully remit from symptoms. The current study explored predictors of treatment response to a group cognitive-behavioural treatment program for pediatric OCD (N=43). Higher levels of child depression and parental rejection at baseline were found to be associated with higher OCD symptoms at post-treatment. Family accommodation was found to be associated with OCD symptom severity at 12-months follow-up. Further, children who were classified as treatment responders at 12-months follow-up had fewer depressive symptoms at baseline than non-responders at 12-months. Results indicate that child depression and adverse family factors may contribute to poorer treatment response for children and youth with OCD. This finding suggests current treatments should be refined for these young people in order to better suit their individual needs., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Background: Depression is a global health challenge. Although there are effective psychological and pharmaceutical interventions, our best treatments achieve remission rates less than 1/3 and limited sustained recovery. Underpinning this efficacy gap is limited understanding of how complex psychological interventions for depression work. Recent reviews have argued that the active ingredients of therapy need to be identified so that therapy can be made briefer, more potent, and to improve scalability. This in turn requires the use of rigorous study designs that test the presence or absence of individual therapeutic elements, rather than standard comparative randomised controlled trials. One such approach is the Multiphase Optimization Strategy, which uses efficient experimentation such as factorial designs to identify active factors in complex interventions. This approach has been successfully applied to behavioural health but not yet to mental health interventions., Methods/design: A Phase III randomised, single-blind balanced fractional factorial trial, based in England and conducted on the internet, randomized at the level of the patient, will investigate the active ingredients of internet cognitive-behavioural therapy (CBT) for depression. Adults with depression (operationalized as PHQ-9 score ≥ 10), recruited directly from the internet and from an UK National Health Service Improving Access to Psychological Therapies service, will be randomized across seven experimental factors, each reflecting the presence versus absence of specific treatment components (activity scheduling, functional analysis, thought challenging, relaxation, concreteness training, absorption, self-compassion training) using a 32-condition balanced fractional factorial design (2 IV 7-2 ). The primary outcome is symptoms of depression (PHQ-9) at 12 weeks. Secondary outcomes include symptoms of anxiety and process measures related to hypothesized mechanisms., Discussion: Better understanding of the active ingredients of efficacious therapies, such as CBT, is necessary in order to improve and further disseminate these interventions. This study is the first application of a component selection experiment to psychological interventions in depression and will enable us to determine the main effect of each treatment component and its relative efficacy, and cast light on underlying mechanisms, so that we can systematically enhance internet CBT., Trial Registration: Current Controlled Trials ISRCTN24117387 . Registered 26 August 2014.

Background: Commercial fusion cages typically provide support in the central region of the endplate, failing to utilize the increased compressive strength around the periphery. This study demonstrates the increase in compressive strength that can be achieved if the bony periphery of the endplate is loaded., Methods: Sixteen cadaveric lumbar vertebrae (L1-L5) were randomly divided into two even groups. A different commercial mass produced implant (MPI) was allocated to each group: (I) a Polyether-ether-ketone (PEEK) anterior lumber inter-body fusion (ALIF) MPI; and (II) a titanium ALIF MPI. Uniaxial compression at a displacement rate of 0.5 mm/sec was applied to all vertebrae during two phases: (I) with the allocated MPI situated in the central region of the endplate; (II) with an aluminum plate, designed to load the bony periphery of the endplate. The failure load and mode of failure was recorded., Results: From phase 1 to phase 2, the failure load increased from 1.1±0.4 to 2.9±1.4 kN for group 1; and from 1.3±1.0 to 3.0±1.9 kN for group 2. The increase in strength from phase 1 to phase 2 was statistically significant for each group (group 1: P<0.01, group 2: P<0.05, paired t -test). There was no significant difference between the groups in either phase (P>0.05, t -test). The mode of failure in phase 1 was the implant being forced through the endplate for both groups. In phase 2, the mode of failure was either a fracture of the epiphyseal rim or buckling of the side wall of the vertebral body., Conclusions: Loading the periphery of the vertebral endplate achieved significant increase in compressive load capacity compared to loading the central region of the endplate. Clinically, this implies that patient-specific implants which load the periphery of the vertebral endplate could decrease the incidence of subsidence and improve surgical outcomes., Competing Interests: The authors have no conflicts of interest to declare.

Objective: Body dysmorphic disorder (BDD) typically starts in adolescence, but evidence-based treatments are yet to be developed and formally evaluated in this age group. We designed an age-appropriate cognitive-behavioral therapy (CBT) protocol for adolescents with BDD and evaluated its acceptability and efficacy in a pilot randomized controlled trial., Method: Thirty adolescents aged 12 to 18 years (mean = 16.0, SD = 1.7) with a primary diagnosis of BDD, together with their families, were randomly assigned to 14 sessions of CBT delivered over 4 months or a control condition of equivalent duration, consisting of written psycho-education materials and weekly telephone monitoring. Blinded evaluators assessed participants at baseline, midtreatment, posttreatment, and at 2-month follow-up. The primary outcome measure was the Yale-Brown Obsessive-Compulsive Scale Modified for BDD, Adolescent Version (mean baseline score = 37.13, SD = 4.98, range = 24-43)., Results: The CBT group showed a significantly greater improvement than the control group, both at posttreatment (time × group interaction coefficient [95% CI] = -11.26 [-17.22 to -5.31]; p = .000) and at 2-month follow-up (time × group interaction coefficient [95% CI] = -9.62 [-15.74 to -3.51]; p = .002). Six participants (40%) in the CBT group and 1 participant (6.7%) in the control condition were classified as responders at both time points (χ(2) = 4.658, p = .031). Improvements were also seen on secondary measures, including insight, depression, and quality of life at posttreatment. Both patients and their families deemed the treatment as highly acceptable., Conclusion: Developmentally tailored CBT is a promising intervention for young people with BDD, although there is significant room for improvement. Further clinical trials incorporating lessons learned in this pilot study and comparing CBT and pharmacological therapies, as well as their combination, are warranted., Clinical Trial Registration Information: Cognitive-Behaviour Therapy for Adolescents With Body Dysmorphic Disorder; http://www.isrctn.com/; ISRCTN67699666., (Copyright © 2015 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.)

Cuttlebone is a natural marine cellular material possessing the exceptional mechanical properties of high compressive strength, high porosity and high permeability. This combination of properties is exceedingly desirable in biomedical applications, such as bone tissue scaffolds. In light of recent studies, which converted raw cuttlebone into hydroxyapatite tissue scaffolds, the impact of morphological variations in the microstructure of this natural cellular material on the effective mechanical properties is explored in this paper. Two extensions of the finite element-based homogenization method are employed to account for deviations from the assumption of periodicity. Firstly, a representative volume element (RVE) of cuttlebone is systematically varied to reflect the large range of microstructural configurations possibly among different cuttlefish species. The homogenization results reveal the critical importance of pillar formation and aspect ratio (height/width of RVE) on the effective bulk and shear moduli of cuttlebone. Secondly, multi-cell analysis domains (or multiple RVE domains) permit the introduction of random variations across neighboring cells. Such random variations decrease the bulk modulus whilst displaying minimal impact on the shear modulus. Increasing the average size of random variations increases the effect on bulk modulus. Also, the results converge rapidly as the size of the analysis domain is increased, meaning that a relatively small multi-cell domain can provide a reasonable approximation of the effective properties for a given set of random variation parameters. These results have important implications for the proposed use of raw cuttlebone as an engineering material. They also highlight some potential for biomimetic design capabilities for materials inspired by the cuttlebone microstructure, which may be applicable in biomedical applications such as bone tissue scaffolds., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Tissue scaffolds aim to provide a cell-friendly biomechanical environment for facilitating cell growth. Existing studies have shown significant demands for generating a certain level of wall shear stress (WSS) on scaffold microstructural surfaces for promoting cellular response and attachment efficacy. Recently, its role in shear-induced erosion of polymer scaffold has also drawn increasing attention. This paper proposes a bi-directional evolutionary structural optimization (BESO) approach for design of scaffold microstructure in terms of the WSS uniformity criterion, by downgrading highly-stressed solid elements into fluidic elements and/or upgrading lowly-stressed fluidic elements into solid elements. In addition to this, a computational model is presented to simulate shear-induced erosion process. The effective stiffness and permeability of initial and optimized scaffold microstructures are characterized by the finite element based homogenization technique to quantify the variations of mechanical properties of scaffold during erosion. The illustrative examples show that a uniform WSS is achieved within the optimized scaffold microstructures, and their architectural and biomechanical features are maintained for a longer lifetime during shear-induced erosion process. This study provides a mathematical means to the design optimization of cellular biomaterials in terms of the WSS criterion towards controllable shear-induced erosion.

The microfluidic environment provided by implanted prostheses has a decisive influence on the viability, proliferation and differentiation of cells. In bone tissue engineering, for instance, experiments have confirmed that a certain level of wall shear stress (WSS) is more advantageous to osteoblastic differentiation. This paper proposes a level-set-based topology optimization method to regulate fluidic WSS distribution for design of cellular biomaterials. The topological boundary of fluid phase is represented by a level-set model embedded in a higher-dimensional scalar function. WSS is determined by the computational fluid dynamics analysis in the scale of cellular base cells. To achieve a uniform WSS distribution at the solid-fluid interface, the difference between local and target WSS is taken as the design criterion, which determines the speed of the boundary evolution in the level-set model. The examples demonstrate the effectiveness of the presented method and exhibit a considerable potential in the design optimization and fabrication of new prosthetic cellular materials for bioengineering applications., (© 2010 Wiley Periodicals, Inc.)

HIV infection recently has been complicated by the emergence of a rare metabolic dysmorphic disorder characterised by fat atrophy, redistribution and accumulation in the setting of hyperlipidaemia and, on occasion, hyperglycaemia. The disorder, sometimes referred to as HIV-associated Adipose Redistribution Syndrome (HARS), has a prevalence rate of about 50 to 60% and seems temporally related to the advent of highly active antiretroviral therapy, especially the usage of protease inhibitors. Various studies also implicate the nucleoside analogues stavudine, didanosine and lamivudine in the pathogenesis of HARS, especially fat atrophy. It is uncertain whether the changes described in HARS represent a single syndrome or a group of related syndromes. Reports have noted differences between morphologic and metabolic changes. More recently, it has been suggested that fat atrophy and fat accumulation may also be separate entities. There are several potential pathogenic theories for HARS that implicate both protease inhibitors and nucleoside analogues as causative agents. However, long term HIV infection rather than any specific agent or class of agent may be the source. Recombinant human growth hormone (rhGH) is a mammalian cell-derived product, which has been useful in a variety of human disorders ranging from pituitary dwarfism to septic shock. It has anabolic, immunological and metabolic properties that restore normal functioning to many aberrant disease pathways. The lipolytic properties of rhGH have been especially beneficial in the diminution of localised fat accumulation in the dorsocervical area (buffalo humps) and truncal region. This has been observed in various reports where rhGH has been administered at doses of 5 to 6 mg/day in patients with HARS for periods ranging from 3 months to >2 years. Relapses after discontinuation of rhGH occurred in most patients. Adverse effects included carpal tunnel syndrome, facial swelling, arthralgias and myalgias and worsening or onset of hyperglycaemia. The small uncontrolled studies conducted to date suggest that the most notable effect of rhGH treatment is the reduction of truncal adiposity and buffalo humps and that the agent has little effect on restoring the adiposity of the appendicular muscles, buttocks or face. Although most patients with HARS have associated hyperlipidaemia, rhGH has no notable effect on serum cholesterol and triglyceride levels. However, blood glucose levels can increase and pre-existent diabetes mellitus may worsen. A short term confirmatory placebo-controlled trial in patients with HARS is urgently needed, as are comparative trials using other anabolic agents such as oxandrolone and testosterone.

This project has been concerned with the comparison of children born as a result of fresh embryo transfer (IVF) with children conceived and born via the natural process. The former included children who were the single outcome of the birth (singletons) and children who were the result of a multiple birth (e.g. twins, triplets). A computer database was established into which was put 23 items of data on each child, making a total of 12,788 items overall. There were 278 "normally conceived" children (controls), 150 IVF Singletons, and 128 children from multiple births. The results show interesting differences in the gestational age at birth, the birth weight, the mode of delivery and the degrees of birth abnormalities and malformations.