Methodology and development of a machine learning probability calculator: Data heterogeneity limits ability to predict recurrence after arthroscopic Bankart repair.

PURPOSE: The aim of this study was to develop and train a machine learning (ML) algorithm to create a clinical decision support tool (i.e., ML-driven probability calculator) to be used in clinical practice to estimate recurrence rates following an arthroscopic Bankart repair (ABR). METHODS: Data from 14 previously published studies were collected. Inclusion criteria were (1) patients treated with ABR without remplissage for traumatic anterior shoulder instability and (2) a minimum of 2 years follow-up. Risk factors associated with recurrence were identified using bivariate logistic regression analysis. Subsequently, four ML algorithms were developed and internally validated. The predictive performance was assessed using discrimination, calibration and the Brier score. RESULTS: In total, 5591 patients underwent ABR with a recurrence rate of 15.4% (n = 862). Age <35 years, participation in contact and collision sports, bony Bankart lesions and full-thickness rotator cuff tears increased the risk of recurrence (all p < 0.05). A single shoulder dislocation (compared to multiple dislocations) lowered the risk of recurrence (p < 0.05). Due to the unavailability of certain variables in some patients, a portion of the patient data had to be excluded before pooling the data set to create the algorithm. A total of 797 patients were included providing information on risk factors associated with recurrence. The discrimination (area under the receiver operating curve) ranged between 0.54 and 0.57 for prediction of recurrence. CONCLUSION: ML was not able to predict the recurrence following ABR with the current available predictors. Despite a global coordinated effort, the heterogeneity of clinical data limited the predictive capabilities of the algorithm, emphasizing the need for standardized data collection methods in future studies. LEVEL OF EVIDENCE: Level IV, retrospective cohort study.

Patient-Reported Outcome Measures Show No Relevant Change Between 1-Year and 2-Year Follow-Up After Treatment for Anterior Shoulder Instability: A Systematic Review.

PURPOSE: To compare patient-reported outcome measures (PROMs) at 1-year and 2-year follow-up after treatment for anterior shoulder instability. METHODS: Randomized controlled trials and prospective studies that evaluated and reported PROMs after a capsulolabral repair (with or without remplissage), bone augmentation, or nonoperative treatment to treat anterior shoulder instability at both 1-year and 2-year follow-up were included. PROMs were compared between 1-year and 2-year follow-up; forest plots with mean difference were created to compare baseline, 1-year, and 2-year follow-up; and scatterplots were created to visualize clinical improvement over time. RESULTS: Fourteen studies, comprising 923 patients, with levels of evidence Level I and II were included. Nine PROMs, of which predominantly were the Western Ontario Shoulder Instability Index (WOSI; 11 studies; 79%), were evaluated. Minimal to no statistically significant change in WOSI, Oxford Shoulder Instability Score, American Shoulder and Elbow Surgeons (ASES), Subjective Shoulder Value, Simple Shoulder Test, Disabilities of Arm, Shoulder, and Hand (DASH), Quick DASH, Single Assessment Numeric Evaluation, or visual analog scale was observed between 1-year and 2-year follow-up. Pooling of the WOSI, Oxford Shoulder Instability Score, ASES, and Single Assessment Numeric Evaluation demonstrated improvement from baseline to 1-year follow-up and minimal to no change between 1-year and 2-year follow-up. Scatterplots of the WOSI and ASES demonstrated the most improvement within 6 months and no clear improvement after 1-year follow-up. Recurrence rates increased with time but varied between studies. CONCLUSIONS: In contrast to recurrence rates, which have been shown to increase with time, minimal to no statistically significant change was observed for any of the included PROMs between 1-year and 2-year follow-up. This finding raises the question as to whether it is necessary to evaluate PROMs in long-term follow-up of patients after shoulder stabilization treatment. LEVEL OF EVIDENCE: Level II, systematic review of Level I and II studies.

Factors associated with the choice of treatment for coronoid fractures.

Aims: This study aimed to gather insights from elbow experts using the Delphi method to evaluate the influence of patient characteristics and fracture morphology on the choice between operative and nonoperative treatment for coronoid fractures. Methods: A three-round electronic (e-)modified Delphi survey study was performed between March and December 2023. A total of 55 elbow surgeons from Asia, Australia, Europe, and North America participated, with 48 completing all questionnaires (87%). The panellists evaluated the factors identified as important in literature for treatment decision-making, using a Likert scale ranging from "strongly influences me to recommend nonoperative treatment" (1) to "strongly influences me to recommend operative treatment" (5). Factors achieving Likert scores ≤ 2.0 or ≥ 4.0 were deemed influential for treatment recommendation. Stable consensus is defined as an agreement of ≥ 80% in the second and third rounds. Results: Of 68 factors considered important in the literature for treatment choice for coronoid fractures, 18 achieved a stable consensus to be influential. Influential factors with stable consensus that advocate for operative treatment were being a professional athlete, playing overhead sports, a history of subjective dislocation or subluxation during trauma, open fracture, crepitation with range of movement, > 2 mm opening during varus stress on radiological imaging, and having an anteromedial facet or basal coronoid fracture (O'Driscoll type 2 or 3). An anterolateral coronoid tip fracture ≤ 2 mm was the only influential factor with a stable consensus that advocates for nonoperative treatment. Most disagreement existed regarding the treatment for the terrible triad injury with an anterolateral coronoid tip fracture fragment ≤ 2 mm (O'Driscoll type 1 subtype 1). Conclusion: This study gives insights into areas of consensus among surveyed elbow surgeons in choosing between operative and nonoperative management of coronoid fractures. These findings should be used in conjunction with previous patient cohort studies when discussing treatment options with patients.

Spatial-social familiarity complements the spatial-social interface: evidence from Yellowstone bison.

Social animals make behavioural decisions based on local habitat and conspecifics, as well as memorized past experience (i.e. 'familiarity') with habitat and conspecifics. Here, we develop a conceptual and empirical understanding of how spatial and social familiarity fit within the spatial-social interface-a novel framework integrating the spatial and social components of animal behaviour. We conducted a multi-scale analysis of the movements of GPS-collared plains bison (Bison bison, n = 66) residing in and around Yellowstone National Park, USA. We found that both spatial and social familiarity mediate how individuals respond to their spatial and social environments. For instance, individuals with high spatial familiarity rely on their own knowledge as opposed to their conspecifics, and individuals with high social familiarity rely more strongly on the movement of conspecifics to guide their own movement. We also found that fine-scale spatial and social phenotypes often scale up to broad-scale phenotypes. For instance, bison that select more strongly to align with their nearest neighbour have larger home ranges. By integrating spatial and social familiarity into the spatial-social interface, we demonstrate the utility of the interface for testing hypotheses, while also highlighting the pervasive importance of cognitive mechanisms in animal behaviour. This article is part of the theme issue 'The spatial-social interface: a theoretical and empirical integration'.

Determinants of pain intensity and magnitude of incapability more than two years after arthroscopic Bankart repair for anterior shoulder instability.

Background: Individuals treated with arthroscopic Bankart repair after anterior shoulder dislocations experience varied discomfort and incapability. The aim of this study was to determine the relative association of mental health and physical health factors with 1) magnitude of capability and 2) pain intensity 2 or more years after surgery. Methods: This cross-sectional study evaluated 80 military patients that experienced one or more traumatic anterior shoulder dislocations a minimum of 2 years after arthroscopic Bankart repair without remplissage. We measured capability (Oxford Shoulder Instability Score), pain intensity using an 11-point ordinal scale, symptoms of anxiety (Generalized Anxiety Disorder-2 questionnaire), symptoms of depression (Patient Health Questionnaire-2), catastrophic thinking (Pain Catastrophizing Scale-4), and kinesiophobia (Tampa scale for kinesiophobia-4). We also identified preoperative presence of a Hill-Sachs lesion on radiographs and postoperative occurrence of subluxation or a dislocation episode. A negative binominal regression analysis sought factors associated with magnitude of incapability and pain intensity. Results: Greater incapability was strongly associated with both greater kinesiophobia (Regression Coefficient [RC] = -0.50; 95% confidence interval [CI] = -0.73 to -0.26; P ≤ .01) and repeat surgery (RC = -0.27; 95% CI = -0.41 to -0.13; P ≤ .01). Greater pain intensity was only strongly associated with greater kinesiophobia (RC = 0.25; 95% CI = 0.039 to 0.46; P = .021). Conclusion: The observation that greater unhelpful thinking is associated with greater pain intensity and greater magnitude of incapability after a Bankart repair for anterior shoulder instability, whereas pathophysiological factors such as glenoid bone loss were not, emphasizes the degree to which mindset is associated with musculoskeletal health.

Type of fixation is not associated with range of motion after operative treatment of proximal radius fractures- a systematic review of 519 patients.

Background: The aims of this study are 1) to assess whether open reduction internal fixation (ORIF) techniques for fractures of the proximal radius are associated with the range of motion (ROM), 2) to determine the incidence of hardware-related complications and removal following plate and screw fixation of the proximal radius, and 3) to evaluate whether the safe-zone definition is described in the literature and its relation to the ROM. Methods: A literature search was performed in the PubMed, Embase, and Cochrane databases. Studies reporting ROM in patients undergoing ORIF for radial head or neck fractures were included. Two treatment groups were defined based on ORIF technique: screws only or plates with and without additional screw placement. Results: A total of 13 articles were included with 519 patients, of which 271 belonged to the screw group and 248 to the plate group. At final follow-up, the screw group reported a mean supination of 79 (95% CI: 74-83), pronation of 76 (95% CI: 69-84), flexion of 131 (95% CI: 124-138), and loss of extension of 4 (95% CI: 1-7). The plate group reported a mean supination of 72 (95% CI: 65-80), pronation of 697 (95% CI: 60-75), flexion of 126 (95% CI: 118-133), and loss of extension of 7 (95% CI: 1-14). Conclusion: Predominantly retrospective studies show that the ROM seems similar for screw and plate osteosynthesis of proximal radius fractures. Complication rates are similar as well. The safe-zone definition is rarely reported.

A brief history of the animals' scientific research, international rules and Brazilian regulations.

Several countries and non-governmental organizations have discussed the use of animals in industry and biomedical areas. This work shows the progression of animal' rights for scientific purposes in Brazil and how Brazilian Councils have advanced to follow worldwide regulations. Since the first rules about animals' usage in Ireland in 1635, the British Cruelty to Animals Act in 1876, and the Brazilian animal protection rules in 1924 and 1934, most worldwide actions culminated in the Universal Declaration of Animal Rights (1978). In 1979, the Brazilian Law 6.638 displayed directives for didactic-scientific practice of vivisection. In 2008, the Arouca Law 11.794 filled regulatory gaps and created the National Council for the Control of Animal Experimentation (CONCEA). In 2014, the CONCEA incorporated the 3R's philosophy and recognized substitute techniques, but only in 2023 it prohibited vertebrate animals in scientific research, development and control of personal hygiene products, cosmetics and perfumes. It is clear current Brazilian and international rules are unable to cover all aspects of animal wellbeing, even for regulations of commercial issues. Certainly, innovative tools, as organ-on-chip, in vitro techniques and bioinformatical advancements will provide a crucial animal welfare and new laws will minimize animal pain and distress, including for disregarded invertebrates.

Choice of Acromioclavicular Dislocation Treatment Should Not Be Influenced by Risk of Development of Acromioclavicular Osteoarthritis: A Systematic Review With Meta-Analysis.

BACKGROUND: It is currently unknown to what degree surgical or nonoperative treatment of acromioclavicular (AC) dislocation influences the development of osteoarthritis (OA). The aim of this study was to evaluate AC OA after surgical and nonoperative treatment for AC dislocations, compare OA prevalence between treatment options, and compare OA prevalence between the injured and contralateral shoulder. METHODS: Articles reporting on the prevalence of OA after surgical or nonoperative treatment of an AC dislocation with a minimal 2-year follow-up were included. AC OA presence was extracted for the injured and contralateral shoulder. Treatment categories were defined based on anatomical variation in the reattachment of ligaments: AC fixation, coracoclavicular (CC) fixation, AC and CC fixation, Bosworth screw synthetic graft, tendon graft, and conservative. Study quality was assessed using the Methodological Index for Non-Randomized Studies (MINORS) criteria. RESULTS: Ninety-four articles were included for qualitative analysis, and 7 articles were included for meta-analysis (n = 3,812; follow-up = 2.0-24.2 years; mean age 37.6 ± 10.4 years). A total of 3,483 patients underwent surgical treatment, and 329 patients underwent conservative treatment. OA prevalence ranged from 6.7%-29.3% between 7 pooled treatment categories. Most included studies had a follow-up <10 years (94%) and OA prevalence increased with time, regardless of treatment option. There was no difference in OA prevalence between the injured and contralateral shoulder (p = 0.120). MINORS scores were varied, ranging from poor to very good. CONCLUSION: The pooled AC OA prevalence of the 7 treatment categories ranged from 6.7% for the CC fixation surgical group to 29.3% for the conservative treatment group. However, the included studies were predominantly of low quality and had varying follow-up periods, with most having relatively short follow-up durations. No difference in AC OA prevalence was found between the injured and contralateral shoulder. Based on the available evidence, treatment choice for AC dislocation should not be influenced by the potential development of AC AO. LEVEL OF EVIDENCE: Level IV. See Instructions for Authors for a complete description of levels of evidence.

Maternal mortality in Eastern Democratic Republic of Congo: a 10-year multi-zonal institutional death review.

BACKGROUND: Maternal mortality (MM) remains a real scourge that hits hardest in the poorest regions of the world, particularly those affected by conflict. However, despite this worrying reality, few studies have been conducted about MM ratio in the Democratic Republic of Congo (DRC). The study aimed to describe the trends as well as the epidemiological profile and causes of reported institutional maternal deaths between 2013 and 2022 in Eastern DRC. METHODS: A retrospective descriptive study was conducted between March 2023 and August 2023 in eight Health Zones (HZ), five in South Kivu Province (Mwana, Minova, Miti-Murhesa, Kamituga and Idjwi) and three in North Kivu Province (Kirotshe, Karisimbi and Kayna) in the eastern region of the DRC. Our study covers 242 health facilities: 168 health centers (HC), 16 referral health centers (RHCs),50 referral hospitals (RH) and 8 general referral hospitals (GRHs). Data from registers and medical records of maternal deaths recorded in these zones from 2013-2022 were extracted along with information on the number of deliveries and live births. Sociodemographic, clinical parameters, blood and ultrasound tests and suspected causes of death between provinces were assessed. RESULTS: In total, we obtained 177 files on deceased women. Of these, 143 (80.8%) were retained for the present study, including 75 in the 3 HZs of North Kivu and 68 in the 5 HZs of South Kivu. From 2013 to 2022, study sites experienced two significant drops in maternal mortality ratio (MMR) (in 2015 and 2018), and a spike in 2016-2017. Nonetheless, the combined MMR (across study sites) started and ended the 10-year study period at approximately the same level (53 and 57 deaths per 100,000 live births in 2013 and 2022 respectively). Overall, 62,6% of the deaths were reported from secondary hospital. Most deaths were of married women in their thirties (93.5%). Almost half (47.8%) had not completed four antenatal consultations. The main direct causes of death were, in decreasing order of frequency: post-partum haemorrhage (55.2%), uterine rupture (14.0), hypertensive disorders (8.4%), abortion (7.7%) puerperal infections (2.8%) and placental abruption (0.7%). When comparing among provinces, reported abortion-related maternal mortality (14.1% vs 0%) was more frequent in North Kivu than in South Kivu. CONCLUSION: This study imperatively highlights the need for targeted interventions to reduce maternal mortality. By emphasizing the crucial importance of antenatal consultations, intrapartum/immediate post-partum care and quality of care, significant progress can be made in guaranteeing maternal health and reducing many avoidable deaths.

A simple CT scan protocol for planning of total hip arthroplasty in patients with femoral neck fractures.

We describe a method for planning total hip arthroplasty (THA) in patients with a displaced femoral neck fracture based on a simple CT scan protocol of the contralateral hip. This protocol was used on 22 consecutive patients during the inclusion period, followed by reconstruction and 2D templating to predict the implant size and positioning. The exact planned size was achieved in 21/22 (95%) cups, 14/22 (64%) femoral stems and 14/22 (64%) femoral heads. There were no intra- or postoperative fractures. After surgery in which this planning method had been applied, the differences in length and lateral offset were less than 5 mm on average relative to the opposite side (mean postoperative leg length difference of -2 mm (-8 to +3 mm) and lateralization of -4 mm (-14 to +3 mm)). While this technique exposes the patient to additional radiation, it does not require any specific devices or surgical approach and could be used in most hospitals. LEVEL OF EVIDENCE: IV.

Numerical simulations suggest asteroids (101955) Bennu and (162173) Ryugu are likely second or later generation rubble piles.

Rubble pile asteroids are widely understood to be composed of reaccumulated debris following a catastrophic collision between asteroids in the main asteroid belt, where each disruption can make a family of new asteroids. Near-Earth asteroids Ryugu and Bennu have been linked to collisional families in the main asteroid belt, but surface age analyses of each asteroid suggest these bodies are substantially younger than their putative families. Here we show, through a coupled collisional and dynamical evolution of members of these families, that neither asteroid was likely to have been created at the same time as the original family breakups, but rather are likely remnants of later disruptions of original family members, making them second, or later, generation remnants. Our model finds about 80% and 60% of asteroids currently being delivered to near-Earth orbits from the respective families of New Polana and Eulalia are second or later generation. These asteroids delivered today in the 0.5-1 km size range have median ages since their last disruption that are substantially younger than the family age, reconciling their measured crater retention ages with membership in these families.

Substantial variability in what is considered important in the radiological report for anterior shoulder instability: a Delphi study with Dutch musculoskeletal radiologists and orthopedic surgeons.

Background: Standardized consensus-based radiological reports for shoulder instability may improve clinical quality, reduce heterogeneity, and reduce workload. Therefore, the aim of this study was to determine important elements for the x-ray, magnetic resonance imaging (MRI) arthrography (MRA), and computed tomography (CT) report, the extent of variability, and important MRI views and settings. Methods: An expert panel of musculoskeletal radiologists and orthopedic surgeons was recruited in a three-round Delphi design. Important elements were identified for the x-ray, MRA, and CT report and important MRI views and setting. These were rated on a 0-9 Likert scale. High variability was defined as at least one score between 1-3 and 7-9. Consensus was reached when ≥80% scored an element 1-3 or 7-9. Results: The expert panel consisted of 21 musculoskeletal radiologists and 15 orthopedic surgeons. The number of elements identified in the first round was seventeen for the x-ray report, 52 for MRA, 21 for CT, and 23 for the MRI protocol. The number of elements that reached consensus was five for x-ray, twenty for MRA, nine for CT, and two for the MRI protocol. High variability was observed in 76.5% (n = 13) x-ray elements, 85.0% (n = 45) MRA, 76.2% (n = 16) CT, and 85.7% (n = 18) MRI protocol. Conclusion: Substantial variability was observed in the scoring of important elements in the radiological for the evaluation of anterior shoulder instability, regardless of modality. Consensus was reached for five elements in the x-ray report, twenty in the MRA report, and nine in the CT report. Finally, consensus was reached on two elements regarding MRA views and settings.

The bearing capacity of asteroid (65803) Didymos estimated from boulder tracks.

The bearing capacity - the ability of a surface to support applied loads - is an important parameter for understanding and predicting the response of a surface. Previous work has inferred the bearing capacity and trafficability of specific regions of the Moon using orbital imagery and measurements of the boulder tracks visible on its surface. Here, we estimate the bearing capacity of the surface of an asteroid for the first time using DART/DRACO images of suspected boulder tracks on the surface of asteroid (65803) Didymos. Given the extremely low surface gravity environment, special attention is paid to the underlying assumptions of the geotechnical approach. The detailed analysis of the boulder tracks indicates that the boulders move from high to low gravitational potential, and provides constraints on whether the boulders may have ended their surface motion by entering a ballistic phase. From the 9 tracks identified with sufficient resolution to estimate their dimensions, we find an average boulder track width and length of 8.9 ± 1.5 m and 51.6 ± 13.3 m, respectively. From the track widths, the mean bearing capacity of Didymos is estimated to be 70 N/m2, implying that every 1 m2 of Didymos' surface at the track location can support only ~70 N of force before experiencing general shear failure. This value is at least 3 orders of magnitude less than the bearing capacity of dry sand on Earth, or lunar regolith.

Evidence for multi-fragmentation and mass shedding of boulders on rubble-pile binary asteroid system (65803) Didymos.

Asteroids smaller than 10 km are thought to be rubble piles formed from the reaccumulation of fragments produced in the catastrophic disruption of parent bodies. Ground-based observations reveal that some of these asteroids are today binary systems, in which a smaller secondary orbits a larger primary asteroid. However, how these asteroids became binary systems remains unclear. Here, we report the analysis of boulders on the surface of the stony asteroid (65803) Didymos and its moonlet, Dimorphos, from data collected by the NASA DART mission. The size-frequency distribution of boulders larger than 5 m on Dimorphos and larger than 22.8 m on Didymos confirms that both asteroids are piles of fragments produced in the catastrophic disruption of their progenitors. Dimorphos boulders smaller than 5 m have size best-fit by a Weibull distribution, which we attribute to a multi-phase fragmentation process either occurring during coalescence or during surface evolution. The density per km2 of Dimorphos boulders ≥1 m is 2.3x with respect to the one obtained for (101955) Bennu, while it is 3.0x with respect to (162173) Ryugu. Such values increase once Dimorphos boulders ≥5 m are compared with Bennu (3.5x), Ryugu (3.9x) and (25143) Itokawa (5.1x). This is of interest in the context of asteroid studies because it means that contrarily to the single bodies visited so far, binary systems might be affected by subsequential fragmentation processes that largely increase their block density per km2. Direct comparison between the surface distribution and shapes of the boulders on Didymos and Dimorphos suggest that the latter inherited its material from the former. This finding supports the hypothesis that some asteroid binary systems form through the spin up and mass shedding of a fraction of the primary asteroid.

Fast boulder fracturing by thermal fatigue detected on stony asteroids.

Spacecraft observations revealed that rocks on carbonaceous asteroids, which constitute the most numerous class by composition, can develop millimeter-to-meter-scale fractures due to thermal stresses. However, signatures of this process on the second-most populous group of asteroids, the S-complex, have been poorly constrained. Here, we report observations of boulders' fractures on Dimorphos, which is the moonlet of the S-complex asteroid (65803) Didymos, the target of NASA's Double Asteroid Redirection Test (DART) planetary defense mission. We show that the size-frequency distribution and orientation of the mapped fractures are consistent with formation through thermal fatigue. The fractures' preferential orientation supports that these have originated in situ on Dimorphos boulders and not on Didymos boulders later transferred to Dimorphos. Based on our model of the fracture propagation, we propose that thermal fatigue on rocks exposed on the surface of S-type asteroids can form shallow, horizontally propagating fractures in much shorter timescales (100 kyr) than in the direction normal to the boulder surface (order of Myrs). The presence of boulder fields affected by thermal fracturing on near-Earth asteroid surfaces may contribute to an enhancement in the ejected mass and momentum from kinetic impactors when deflecting asteroids.

Lessons from PROMINENT and prospects for pemafibrate.

The neutral result of the PROMINENT trial has led to questions about the future for pemafibrate. This commentary discusses possible reasons for the lack of benefit observed in the trial. There were, however, indicators suggesting therapeutic potential in microvascular ischaemic complications associated with peripheral artery disease, with subsequent analysis showing reduction in the incidence of lower extremity ischaemic ulceration or gangrene. Reassurance about the safety of pemafibrate, together with emerging data from PROMINENT and experimental studies, also suggest benefit with pemafibrate in non-alcoholic fatty liver disease (alternatively referred to as metabolic dysfunction-associated steatotic liver disease) and microangiopathy associated with diabetes, which merit further study.

Better operating room efficiency and reduced staff demand: Individualised versus off-the-shelf total knee arthroplasty.

PURPOSE: The purpose of this pilot cross-sectional study was to compare the operating room (OR) efficiency and intraoperative staff task load when performing individualised versus off-the-shelf (OTS) total knee arthroplasty (TKA). METHODS: A consecutive series of 28 patients randomised (1:1) to receive either OTS TKA or individualised TKA were included. The OR staff workload was assessed with the NASA Task Load Index (TLX), a subjective grading system assessing mental demand, physical demand, temporal demand, performance, effort and frustration on a scale from 0 (very low) to 20 (very high). The time for patient preparation, surgical time, closure and total OR time was recorded to assess OR efficiency. Effect sizes of differences between OTS and individualised TKA were expressed as mean differences (MDs) with 95% confidence intervals (CIs). RESULTS: Patients in both cohorts were similar in age (OTS vs. individualised TKA (median [IQR]), 67 [63-76] vs. 71 [68-79]; p = 0.207) and body mass index (BMI) (29 [24-33] vs. 29 [26-31]; p = 0.807), and there were no significant differences in other preoperative characteristics. The OR staff perceived individualised TKA as less demanding than OTS TKA: Individualised TKA was rated significantly better across the six domains of the NASA TLX: mental demand by 5.6 points, physical demand by 6.3 points, temporal demand by 5.3 points, performance by 3.6 points, effort by 5.9 points and frustration by 5.8 points. Individualised TKA resulted in statistically significantly shorter mean total OR time (MD, 10 min; p = 0.018). CONCLUSION: The staff in the OR found that individualised TKA is less mentally, physically and temporally demanding than OTS TKA. The average total time spent in the OR during individualised TKA is 10 min less than during OTS TKA. CLINICAL TRIAL REGISTRATION: This study constitutes a part of a larger registered randomised controlled trial comparing patient satisfaction following OTS versus individualised TKA (NCT04460989). LEVEL OF EVIDENCE: Level III.

Individualised compared to off-the-shelf total knee arthroplasty results in lower and less variable patellar tilt.

PURPOSE: The purpose of this study was to compare postoperative patellar tilt at 4 months follow-up in a consecutive series of randomised patients that received individualised or off-the-shelf (OTS) primary total knee arthroplasty (TKA). The hypothesis was that patellar tilt would be lower and less variable in patients who received individualised TKA compared to patients who received OTS TKA. METHODS: A consecutive series of 385 patients randomised (1:1) to receive either OTS TKA or individualised TKA were analysed. Pre- and postoperative radiographs at 4 months were obtained of weight-bearing long leg, anterior-posterior and lateral knee views and a skyline view at 30° of flexion. Postoperative patellar tilt was measured between the anterior femoral line and patellar resection surface (ß) and the anterior femoral line and mediolateral patellar axis (σ). Postoperative patellar tilt (absolute value) was compared between the individualised and OTS TKA groups based on preoperative phenotypes of their femoral mechanical angle, tibial mechanical angle and hip-knee-ankle angle. Variability in postoperative patellar tilt was compared using the 95% confidence intervals (CIs). RESULTS: Comparisons of baseline patient characteristics revealed no difference between the individualised and OTS TKA groups. Comparison of absolute postoperative patellar tilt revealed significant differences between individualised and OTS TKA (|ß|, 1.0° ± 1.0° and 2.5° ± 2.2°, respectively, p < 0.001; |σ|, 1.7° ± 1.6° and 2.8° ± 2.3°, respectively, p < 0.001). The 95% CI of postoperative patellar tilt (|ß|) was narrower in patients that received individualised compared to OTS TKA (0.0° to 3.8° and 0.1° to 8.3°, respectively), irrespective of their preoperative phenotype. CONCLUSION: Patients who underwent individualised TKA had lower and less variable postoperative patellar tilt than those with OTS TKA, irrespective of preoperative phenotype. Individualised TKA allows the decoupling of the tibiofemoral and patellofemoral joints, replicating anatomical trochlear orientation and improving patellar tilt, which could facilitate better clinical outcomes. CLINICAL TRIAL REGISTRATION: This study constitutes a part of a larger registered randomised controlled trial comparing patient satisfaction following OTS versus individualised TKA (NCT04460989). LEVEL OF EVIDENCE: Level II.

Inverse bremsstrahlung absorption rate for super-Gaussian electron distribution functions including plasma screening.

We provide analytic expressions for the effective Coulomb logarithm for inverse bremsstrahlung absorption which predict significant corrections to the Langdon effect and overall absorption rate compared to previous estimates. The calculation of the collisional absorption rate of laser energy in a plasma by the inverse bremsstrahlung mechanism usually makes the approximation of a constant Coulomb logarithm. We dispense with this approximation and instead take into account the velocity dependence of the Coulomb logarithm, leading to a more accurate expression for the absorption rate valid in both classical and quantum conditions. In contrast to previous work, the laser intensity enters into the Coulomb logarithm. In most laser-plasma interactions the electron distribution function is super-Gaussian [Langdon, Phys. Rev. Lett. 44, 575 (1980)0031-900710.1103/PhysRevLett.44.575], and we find the absorption rate under these conditions is increased by as much as ≈30% compared to previous estimates at low density. In many cases of interest the correction to Langdon's predicted reduction in absorption is large; for example at Z=6 and T_{e}=400eV the Langdon prediction for the absorption is in error by a factor of ≈2. However, we also account for the additional effect of plasma screening, which predicts a reduction in absorption by a similar amount (up to ≈30%). These two effects compete to determine the overall absorption, which may be increased or decreased, depending on the conditions. The corrections can be incorporated into radiation-hydrodynamics simulation codes by replacing the familiar Coulomb logarithm with an analytic expression which depends on the super-Gaussian order "M" and the screening length.