Biotinylated Photocleavable Semiconductor Colloidal Quantum Dot Supraparticle Microlaser.

Luminescent supraparticles of colloidal semiconductor nanocrystals can act as microscopic lasers and are hugely attractive for biosensing, imaging, and drug delivery. However, biointerfacing these to increase functionality while retaining their main optical properties remains an unresolved challenge. Here, we propose and demonstrate red-emitting, silica-coated CdSxSe1-x/ZnS colloidal quantum dot supraparticles functionalized with a biotinylated photocleavable ligand. The success of each step of the synthesis is confirmed by scanning electron microscopy, energy dispersive X-ray and Fourier transform infrared spectroscopy, ζ-potential, and optical pumping measurements. The capture and release functionality of the supraparticle system is proven by binding to a neutravidin functionalized glass slide and subsequently cleaving off after UV-A irradiation. The biotinylated supraparticles still function as microlasers; e.g., a 9 µm diameter supraparticle has oscillating modes around 625 nm at a threshold of 58 mJ/cm2. This work is a first step toward using supraparticle lasers as enhanced labels for bionano applications.

Relationship between staff and quality of care in care homes: StaRQ mixed methods study.

Background: Quality of life and care varies between and within the care homes in which almost half a million older people live and over half a million direct care staff (registered nurses and care assistants) work. The reasons are complex, understudied and sometimes oversimplified, but staff and their work are a significant influence. Objective(s): To explore variations in the care home nursing and support workforce; how resident and relatives' needs in care homes are linked to care home staffing; how different staffing models impact on care quality, outcomes and costs; how workforce numbers, skill mix and stability meet residents' needs; the contributions of the care home workforce to enhancing quality of care; staff relationships as a platform for implementation by providers. Design: Mixed-method (QUAL-QUANT) parallel design with five work packages. WP1 - two evidence syntheses (one realist); WP2 - cross-sectional survey of routine staffing and rated quality from care home regulator; WP3 - analysis of longitudinal data from a corporate provider of staffing characteristics and quality indicators, including safety; WP4 - secondary analysis of care home regulator reports; WP5 - social network analysis of networks likely to influence quality innovation. We expressed our synthesised findings as a logic model. Setting: English care homes, with and without nursing, with various ownership structures, size and location, with varying quality ratings. Participants: Managers, residents, families and care home staff. Findings: Staffing's contribution to quality and personalised care requires: managerial and staff stability and consistency; sufficient staff to develop 'familial' relationships between staff and residents, and staff-staff reciprocity, 'knowing' residents, and skills and competence training beyond induction; supported, well-led staff seeing modelled behaviours from supervisors; autonomy to act. Outcome measures that capture the relationship between staffing and quality include: the extent to which resident needs and preferences are met and culturally appropriate; resident and family satisfaction; extent of residents living with purpose; safe care (including clinical outcomes); staff well-being and job satisfaction were important, but underacknowledged. Limitations: Many of our findings stem from self-reported and routine data with known biases - such as under reporting of adverse incidents; our analysis may reflect these biases. COVID-19 required adapting our original protocol to make it feasible. Consequently, the effects of the pandemic are reflected in our research methods and findings. Our findings are based on data from a single care home operator and so may not be generalised to the wider population of care homes. Conclusions: Innovative and multiple methods and theory can successfully highlight the nuanced relationship between staffing and quality in care homes. Modifiable characteristics such as visible philosophies of care and high-quality training, reinforced by behavioural and relational role modelling by leaders can make the difference when sufficient amounts of consistent staff are employed. Greater staffing capacity alone is unlikely to enhance quality in a cost-effective manner. Social network analysis can help identify the right people to aid adoption and spread of quality and innovation. Future research should focus on richer, iterative, evaluative testing and development of our logic model using theoretically and empirically defensible - rather than available - inputs and outcomes. Study registration: This study is registered as PROSPERO CRD42021241066 and Research Registry registration: 1062. Funding: This award was funded by the National Institute for Health and Care Research (NIHR) Health and Social Care Delivery Research programme (NIHR award ref: 15/144/29) and is published in full in Health and Social Care Delivery Research; Vol. 12, No. 8. See the NIHR Funding and Awards website for further award information.

This study was about the relationship between staffing and quality in care homes. Almost half a million older people live in care homes in England. Why quality of care and quality of life for residents vary so much between and within homes is unknown, but staff and the ways they work are likely to be important. Researching staffing and quality is difficult: quality means different things to different people and a lot of things shape how quality feels to residents, families and staff. In the past, researchers have oversimplified the problem to study it and may have missed important influences. We took a more complex view. In five interlinked work packages, we collected and analysed: (1) research journal articles; (2) national data from different care homes; (3) data from a large care organisation to look at what it is about staffing that influences quality; (4) reports and ratings of homes from the Care Quality Commission; and (5) we looked at the networks between staff in homes that shape how quality improvement techniques might spread. We used theories about how our findings might be linked to plan for this data collection and analysis. The results were combined into something called a 'logic model' ­ a diagram and explanation that make it easier for managers, researchers and people interested in care homes to see how staffing influences quality. Staffing considerations that might improve quality include: not swapping managers too much; having sufficient and consistent staff for family-like relationships in homes and putting residents' needs first; supporting staff and giving them freedom to act; and key staff leading by example. Research examining care home quality should capture those aspects that mean the most to residents, their families and staff.

Waveguide-Integrated Colloidal Nanocrystal Supraparticle Lasers.

Supraparticle (SP) microlasers fabricated by the self-assembly of colloidal nanocrystals have great potential as coherent optical sources for integrated photonics. However, their deterministic placement for integration with other photonic elements remains an unsolved challenge. In this work, we demonstrate the manipulation and printing of individual SP microlasers, laying the foundation for their use in more complex photonic integrated circuits. We fabricate CdSxSe1-x/ZnS colloidal quantum dot (CQD) SPs with diameters from 4 to 20 µm and Q-factors of approximately 300 via an oil-in-water self-assembly process. Under a subnanosecond-pulse optical excitation at 532 nm, the laser threshold is reached at an average number of excitons per CQD of 2.6, with modes oscillating between 625 and 655 nm. Microtransfer printing is used to pick up individual CQD SPs from an initial substrate and move them to a different one without affecting their capability for lasing. As a proof of concept, a CQD SP is printed on the side of an SU-8 waveguide, and its modes are successfully coupled to the waveguide.

Simultaneous Growth Strategy of High-Optical-Efficiency GaN NWs on a Wide Range of Substrates by Pulsed Laser Deposition.

Here, we explore a catalyst-free single-step growth strategy that results in high-quality self-assembled single-crystal vertical GaN nanowires (NWs) grown on a wide range of common and novel substrates (including GaN, Ga2O3, and monolayer two-dimensional (2D) transition-metal dichalcogenide (TMD)) within the same chamber and thus under identical conditions by pulsed laser deposition. High-resolution transmission electron microscopy and scanning transmission electron microscopy (HR-STEM) and grazing incidence X-ray diffraction measurements confirm the single-crystalline nature of the obtained NWs, whereas advanced optical and cathodoluminescence measurements provide evidence of their high optical quality. Further analyses reveal that the growth is initiated by an in situ polycrystalline layer formed between the NWs and substrates during growth, while as its thickness increases, the growth mode transforms into single-crystalline NW nucleation. HR-STEM and corresponding energy-dispersive X-ray compositional analyses indicate possible growth mechanisms. All samples exhibit strong band edge UV emission (with a negligible defect band) dominated by radiative recombination with a high optical efficiency (∼65%). As all NWs have similar structural and optical qualities irrespective of the substrate used, this strategy will open new horizons for developing III-nitride-based devices.

Anterior capsulectomy versus repair in direct anterior total hip arthroplasty.

BACKGROUND: Utilization of the direct anterior approach for total hip arthroplasty (DAA THA) has increased over the last ten years. The preservation and repair of the anterior hip capsule has been recommended, while anterior capsulectomy has been described by others. In contrast, the higher risk of posterior dislocation using the posterior approach improved significantly after capsular repair. No studies to date have investigated outcome scores based on capsular repair versus capsulectomy for the DAA. METHODS: Patients randomized to anterior capsulectomy or anterior capsule repair. Patients were blinded to their randomization. Maximum hip flexion was measured both radiographically and clinically with a goniometer. Using a one-sided t test assuming equal variance with an effect size, Cohen's d, of 0.6 and an alpha of 0.05, 36 patients in each group (total 72 patients) needed for a minimum 80% power. RESULTS: Median goniometer measurements preoperatively were 95° for repair (IQR 85-100) and 91° for capsulectomy (IQR 82-97.5) (p = 0.52). Four-month and one-year goniometer measurements also had no significant difference, 110° (IQR 105-120) and 110° (IQR 105-120) for repair and 105° (IQR 96-116) and 109° (IQR 102-120) for capsulectomy (p = 0.38 and p = 0.26). Median change in flexion as measured by goniometer at 4 months and one year was 12 and 9 degrees for repair and 9.5 and 3 degrees for capsulectomy (p = 0.53 and p = 0.46). X-ray analysis showed no differences in pre-op, 4-month, and one-year flexion with median one-year flexion of 105.5° (IQR 96-109.5) for repair and 100° (IQR 93.5-112) for capsulectomy (p = 0.35). VAS scores were the same for both groups at all three time points. HOOS scores improved equally for both groups. There are no differences in surgeon randomization, age, or gender. CONCLUSIONS: Both capsular repair and capsulectomy used in direct anterior approach THA result in equal maximum clinical as well as radiographic hip flexion with no change in postoperative pain or HOOS scores.

Comparison of tumor-informed and tumor-naïve sequencing assays for ctDNA detection in breast cancer.

Analysis of circulating tumor DNA (ctDNA) to monitor cancer dynamics and detect minimal residual disease has been an area of increasing interest. Multiple methods have been proposed but few studies have compared the performance of different approaches. Here, we compare detection of ctDNA in serial plasma samples from patients with breast cancer using different tumor-informed and tumor-naïve assays designed to detect structural variants (SVs), single nucleotide variants (SNVs), and/or somatic copy-number aberrations, by multiplex PCR, hybrid capture, and different depths of whole-genome sequencing. Our results demonstrate that the ctDNA dynamics and allele fractions (AFs) were highly concordant when analyzing the same patient samples using different assays. Tumor-informed assays showed the highest sensitivity for detection of ctDNA at low concentrations. Hybrid capture sequencing targeting between 1,347 and 7,491 tumor-identified mutations at high depth was the most sensitive assay, detecting ctDNA down to an AF of 0.00024% (2.4 parts per million, ppm). Multiplex PCR targeting 21-47 tumor-identified SVs per patient detected ctDNA down to 0.00047% AF (4.7 ppm) and has potential as a clinical assay.

Systematic review of marine environmental DNA metabarcoding studies: toward best practices for data usability and accessibility.

The emerging field of environmental DNA (eDNA) research lacks universal guidelines for ensuring data produced are FAIR-findable, accessible, interoperable, and reusable-despite growing awareness of the importance of such practices. In order to better understand these data usability challenges, we systematically reviewed 60 peer reviewed articles conducting a specific subset of eDNA research: metabarcoding studies in marine environments. For each article, we characterized approximately 90 features across several categories: general article attributes and topics, methodological choices, types of metadata included, and availability and storage of sequence data. Analyzing these characteristics, we identified several barriers to data accessibility, including a lack of common context and vocabulary across the articles, missing metadata, supplementary information limitations, and a concentration of both sample collection and analysis in the United States. While some of these barriers require significant effort to address, we also found many instances where small choices made by authors and journals could have an outsized influence on the discoverability and reusability of data. Promisingly, articles also showed consistency and creativity in data storage choices as well as a strong trend toward open access publishing. Our analysis underscores the need to think critically about data accessibility and usability as marine eDNA metabarcoding studies, and eDNA projects more broadly, continue to proliferate.

Re-interpreting tumour behaviour and the tumour microenvironment as normal responses to tissue disorganisation.

Much of tumour cell biology and the tumour microenvironment may be normal wound-healing responses as a consequence of the disruption of tissue structure. This is why tumours resemble wounds, and many features of the tumour microenvironment, such as the epithelial-mesenchymal transition, cancer-associated fibroblasts, and inflammatory infiltrates, may largely be normal responses to abnormal tissue structure, not an exploitation of wound-healing biology. © 2023 The Author. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Core-Shell Nanorods as Ultraviolet Light-Emitting Diodes.

Existing barriers to efficient deep ultraviolet (UV) light-emitting diodes (LEDs) may be reduced or overcome by moving away from conventional planar growth and toward three-dimensional nanostructuring. Nanorods have the potential for enhanced doping, reduced dislocation densities, improved light extraction efficiency, and quantum wells free from the quantum-confined Stark effect. Here, we demonstrate a hybrid top-down/bottom-up approach to creating highly uniform AlGaN core-shell nanorods on sapphire repeatable on wafer scales. Our GaN-free design avoids self-absorption of the quantum well emission while preserving electrical functionality. The effective junctions formed by doping of both the n-type cores and p-type caps were studied using nanoprobing experiments, where we find low turn-on voltages, strongly rectifying behaviors and significant electron-beam-induced currents. Time-resolved cathodoluminescence measurements find short carrier liftetimes consistent with reduced polarization fields. Our results show nanostructuring to be a promising route to deep-UV-emitting LEDs, achievable using commercially compatible methods.

Focused cardiac ultrasound in pregnancy.

Cardiac disease in pregnancy is an important cause of maternal morbidity and mortality. In many high-income countries, acquired cardiac disease is now the largest cause of maternal mortality. Given its prevalence in low- and middle-income countries (LMICs), rheumatic heart disease is the most common cause of cardiac disease in pregnancy worldwide and is associated with poor maternal outcome. The diagnosis of cardiac disease in pregnancy is often delayed resulting in excess maternal morbidity and mortality. Maternal mortality review committees have suggested that prompt recognition and treatment of heart disease in pregnancy may improve maternal outcome. Given the similarities between symptoms of normal pregnancy and those of cardiac disease, the clinical diagnosis of heart disease in pregnancy is challenging with echocardiography being the primary diagnostic modality. Focused cardiac ultrasound (FOCUS) at the point of care provides supplemental data to the history and physical examination and has been demonstrated to permit early diagnosis and improvement in the management of cardiac disease in emergency medicine, intensive care, and anesthesia. It has also been demonstrated to be useful in surveillance for rheumatic heart disease in LMICs. The use of FOCUS may allow earlier and more accurate diagnosis of cardiac disease in pregnancy with the potential to decrease morbidity and mortality in both developed and developing countries.

Synthesis of Plasmonically Active Titanium Nitride Using a Metallic Alloy Buffer Layer Strategy.

Titanium nitride (TiN) has emerged as a highly promising alternative to traditional plasmonic materials. This study focuses on the inclusion of a Cr90Ru10 buffer layer between the substrate and thin TiN film, which enables the use of cost-effective, amorphous technical substrates while preserving high film quality. We report best-in-class TiN thin films fabricated on fused silica wafers, achieving a maximum plasmonic figure of merit, -ϵ'/ϵ″, of approximately 2.8, even at a modest wafer temperature of around 300 °C. Furthermore, we delve into the characterization of TiN thin film quality and fabricated TiN triangular nanostructures, employing attenuated total reflectance and cathodoluminescence techniques to highlight their potential applications in surface plasmonics.

Supporting nurse leaders to recognise and mitigate the effects of moral injury.

The concept of moral injury has been around for several decades, yet its effect on nurses remains under-recognised. Moral injury is defined as the biopsychosocial harm that arises from a violation of one's moral code, meaning that a person is powerless to uphold and enact what they believe is morally right. The coronavirus disease 2019 (COVID-19) pandemic has brought the issue of moral injury into focus because many nurses and other healthcare professionals have encountered potentially morally injurious events, resulting in increased pressure and emotional demands. It is essential that nurse leaders recognise moral injury if its effects are to be addressed. This article describes moral injury and its effects on nurses, and offers nurse leaders a practical framework for mitigating this issue. The framework aims to support nurse leaders to increase their understanding of moral injury, address any ethical challenges, ensure they are adequately prepared to provide support to nurses, and enhance their awareness of various interventions that can mitigate moral injury.

Metformin suppresses pro-inflammatory cytokines in vitreous of diabetes patients and human retinal vascular endothelium.

Metformin is a traditional anti-hyperglycemic medication that has recently been shown to benefit vascular complications of diabetes via an anti-inflammatory mechanism other than glycemic control. This study aims to test the hypothesis that metformin suppresses diabetic retinopathy (DR) associated intraocular inflammation. Human vitreous from control and proliferative diabetic retinopathy (PDR) patients with or without long-term metformin treatment (> 5 years) were collected for multiple inflammatory cytokines measurements with a cytokine array kit. The vast majority of the measurable cytokines in PDR vitreous has a lower level in metformin group than non-metformin group. Although the p values are not significant due to a relatively small sample size and large deviations, the 95% confidence interval (CI) for the mean difference between the two groups shows some difference in the true values should not be neglected. Using quantitative ELISA, soluble intercellular adhesion molecule -1 (ICAM-1) and monocyte chemoattractant protein -1 (MCP-1) presented with significantly lower concentrations in metformin group versus non-metformin group. Metformin group also has significantly less up-regulated cytokines and diminished positive correlations among the cytokines when compared to non-metformin group. Possible role of AMP-activated protein kinase (AMPK) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) in metformin's anti-inflammatory effects were studied in human retinal vascular endothelial cells (hRVECs) cultured in normal glucose (NG) and high glucose (HG) conditions. Metformin inhibited HG-induced ICAM-1, IL-8, and MCP-1 via AMPK activation, whereas pharmacological AMPK inhibition had no effect on its inhibition of NF-κB p65, sICAM-1, and tumor necrosis factor-α (TNF-α). Metformin-induced suppression of the inflammatory cytokines could also be mediated through its direct inhibition of NF-κB, independent of AMPK pathway. This is a proof-of-concept study that found metformin treatment was associated with reduced inflammatory responses in vitreous of diabetes patients and retinal vascular endothelial cells, supporting the rationale for using metformin to treat DR at an early stage.

The impact of dental curriculum format on student performance on the national board dental examination.

PURPOSE/OBJECTIVE: The effectiveness of different curriculum types has long been debated by dental educators aiming to provide the best education possible to their students. This study aimed to evaluate the effect of curriculum type (hybrid problem-based learning [PBL] vs. traditional) on National Board Dental Examination (NBDE) part I and II pass rates METHODS: A retrospective cohort study was conducted with a hybrid PBL cohort and traditional cohort. NBDE part I and II pass rates for the two cohorts were acquired, along with demographic and scholastic variables. Pass rates, scholastic variables, and demographic variables were compared using two-sample t-tests and chi-square tests. Associations of the variables with pass rates were analyzed using logistic regression. Significance was set at 5% RESULTS: No significant differences in pass rates for NBDE part I and II were observed between the cohorts. Cumulative dental school grade point average (GPA) was found to be an independent predictor of success for NBDE part I (odds ratio (OR): 1.40, 1.24-1.59 for 0.1 point intervals) and II (OR: 1.34, 1.18-1.52 for 0.1 point intervals), (p < 0.01). DAT biology sub-score was found to be predictive of success for NBDE part I (OR: 1.58, 1.14-2.19), (p = 0.01) CONCLUSIONS: No significant difference in NBDE part I and II pass rates between the cohorts was found. Dental school GPA was the most predictive variable for success on NBDE part I and II. These findings may be helpful considerations as institutions assess the structure of their school curricula.

Assessing the Impact of Secondary Fluorescence on X-Ray Microanalysis Results from Semiconductor Thin Films.

The impact of secondary fluorescence on the material compositions measured by X-ray analysis for layered semiconductor thin films is assessed using simulations performed by the DTSA-II and CalcZAF software tools. Three technologically important examples are investigated: AlxGa1−xN layers on either GaN or AlN substrates, InxAl1−xN on GaN, and Si-doped (SnxGa1−x)2O3 on Si. Trends in the differences caused by secondary fluorescence are explained in terms of the propensity of different elements to reabsorb either characteristic or bremsstrahlung X-rays and then to re-emit the characteristic X-rays used to determine composition of the layer under investigation. Under typical beam conditions (7­12 keV), the quantification of dopants/trace elements is found to be susceptible to secondary fluorescence and care must be taken to prevent erroneous results. The overall impact on major constituents is shown to be very small with a change of approximately 0.07 molar cation percent for Al0.3Ga0.7N/AlN layers and a maximum change of 0.08 at% in the Si content of (SnxGa1−x)2O3/Si layers. This provides confidence that previously reported wavelength-dispersive X-ray compositions are not compromised by secondary fluorescence.

Determination of H-Atom Positions in Organic Crystal Structures by NEXAFS Combined with Density Functional Theory: a Study of Two-Component Systems Containing Isonicotinamide.

It is important to be able to identify the precise position of H-atoms in hydrogen bonding interactions to fully understand the effects on the structure and properties of organic crystals. Using a combination of near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and density functional theory (DFT) quantum chemistry calculations, we demonstrate the sensitivity of core-level X-ray spectroscopy to the precise H-atom position within a donor-proton-acceptor system. Exploiting this sensitivity, we then combine the predictive power of DFT with the experimental NEXAFS, confirming the H-atom position identified using single-crystal X-ray diffraction (XRD) techniques more easily than using other H-atom sensitive techniques, such as neutron diffraction. This proof of principle experiment confirms the H-atom positions in structures obtained from XRD, providing evidence for the potential use of NEXAFS as a more accurate and easier method of locating H-atoms within organic crystals.

Human health implications from consuming eggs produced near a derelict metalliferous mine: a case study.

Lead pollution from metalliferous mines can have major environmental and health effects long after the mines have closed. Animals living near derelict mine sites can inadvertently ingest lead-contaminated soils, causing them to accumulate lead and potentially experience significant adverse health effects. Human food products, such as eggs, produced near metalliferous mines may also be contaminated with lead. The focus of this case study was to determine whether free-range chickens living near a derelict lead mine had high lead body burdens, whether they were producing eggs with elevated lead concentrations, and whether these eggs could be hazardous to human health. Soil samples and chicken egg, feather, blood, and bone samples were collected from a small farm near an abandoned metalliferous mine. The soil in and around the chicken pens contained lead concentrations that were elevated above established soil lead baseline concentrations. The lead concentrations in the chicken feather, blood, and bone samples were consistent with lead toxicity and indicated long-term, continuous exposure. Finally, the lead concentrations in the eggs were significantly greater than those found in commercial eggs. Based on previously established lead benchmark dose levels, humans, and in particular, children, could experience adverse health impacts if they routinely consumed these eggs. Environmental lead contamination continues to pose a major health risk for humans, and further research, understanding, and awareness are required to safeguard the public from the risks of consuming food produced near derelict mines.

Rearrangement processes and structural variations show evidence of selection in oesophageal adenocarcinomas.

Oesophageal adenocarcinoma (OAC) provides an ideal case study to characterize large-scale rearrangements. Using whole genome short-read sequencing of 383 cases, for which 214 had matched whole transcriptomes, we observed structural variations (SV) with a predominance of deletions, tandem duplications and inter-chromosome junctions that could be identified as LINE-1 mobile element (ME) insertions. Complex clusters of rearrangements resembling breakage-fusion-bridge cycles or extrachromosomal circular DNA accounted for 22% of complex SVs affecting known oncogenes. Counting SV events affecting known driver genes substantially increased the recurrence rates of these drivers. After excluding fragile sites, we identified 51 candidate new drivers in genomic regions disrupted by SVs, including ETV5, KAT6B and CLTC. RUNX1 was the most recurrently altered gene (24%), with many deletions inactivating the RUNT domain but preserved the reading frame, suggesting an altered protein product. These findings underscore the importance of identification of SV events in OAC with implications for targeted therapies.

Inter-Rater Reliability of Clinical Testing for Laxity After Knee Arthroplasty.

BACKGROUND: The clinical examination for laxity has been considered a mainstay in evaluation of the painful knee arthroplasty, especially for the diagnosis of instability. More than 10 mm of anterior-posterior (AP) translation in flexion has been described as important in the diagnosis of flexion instability. The inter-observer reliability of varus/valgus and AP laxity testing has not been tested. METHODS: Ten subjects with prior to total knee arthroplasty (TKA) were examined by 4 fellowship-trained orthopedic knee arthroplasty surgeons. Each surgeon evaluated each subject in random order and was blinded to the results of the other surgeons. Each surgeon performed an anterior drawer test at 30 and 90 degrees of flexion and graded the instability as 0-5 mm, 5-10 mm or >10 mm. Varus-valgus testing was also graded. Motion capture was used during the examination to determine the joint position and estimate joint reaction force during the examination. RESULTS: Inter-rater reliability (IRR) was poor at 30 and 90 degrees for both the subjective rater score and the measured AP laxity in flexion (k = 018-0.22). Varus-valgus testing similarly had poor reliability. Force applied by the rater also had poor IRR. CONCLUSION: Clinical testing of knee laxity after TKA has poor reliability between surgeons using motion analysis. It is unclear if this is from differences in examiner technique or from differences in pain or quadriceps function of the subjects. Instability after TKA should not be diagnosed strictly by clinical testing and should involve a complete clinical assessment of the patient.