Search results
Found 31107 matches for
Comparison of five-year clinical outcomes of 524 cemented and cementless medial unicompartmental knee replacements.
AIM: To compare the outcomes of cemented and cementless Unicompartmental Knee Replacements (UKR) at 5 years after surgery. METHODS: 262 cemented and 262 cementless medial mobile-bearing UKR, implanted by four high-volume surgeons using identical indications and surgical techniques, were reviewed by independent physiotherapists at 5 years. Survival, Oxford Knee Score (OKS), American Knee Society Score (AKSS), and EQ-5D-5L were assessed. The cementless cohort was mainly implanted after the cemented. Each cohort was divided into early and late sub-groups and compared, to assess if any differences were due to progressive improvement in surgical practice over time. RESULTS: There were no significant differences between the cohorts for demographics, pre-operative scores, and 5-year revision (0.8%), re-operation (1.5%), and complication rates (5%). The cementless cohort had significantly better 5-year OKS (43v41, p = 0.008), AKSS-Objective (94v90, p = 0.049) and EQ-5D-5L (0.81v0.87, p = 0.0001). Pain sub-scores within OKS, AKSS, and EQ-5D-5L were also significantly better in the cementless cohort, and the differences were proportionally much greater and more significant than differences in their respective overall scores. There was no significant improvement in scores between the early and late subgroups of the cohorts, whereas the 'early-cementless' cohort had significantly better scores than the contemporaneously implanted 'late-cemented' cohort. This suggests that differences found were due to implant type, instead of improved surgical practice over time. CONCLUSION: Cementless UKR is associated with better clinical outcomes than cemented UKR, which is primarily due to improved pain relief. Both cemented and cementless UKR are safe with low reoperation and complication rates, and a 5-year survival of 99%.
Extended sample size calculations for evaluation of prediction models using a threshold for classification.
When evaluating the performance of a model for individualised risk prediction, the sample size needs to be large enough to precisely estimate the performance measures of interest. Current sample size guidance is based on precisely estimating calibration, discrimination, and net benefit, which should be the first stage of calculating the minimum required sample size. However, when a clinically important threshold is used for classification, other performance measures are also often reported. We extend the previously published guidance to precisely estimate threshold-based performance measures. We have reported closed-form solutions to estimate the sample size required to target sufficiently precise estimates of accuracy, specificity, sensitivity, positive predictive value (PPV), negative predictive value (NPV), and an iterative method to estimate the sample size required to target a sufficiently precise estimate of the F1-score, in an external evaluation study of a prediction model with a binary outcome. This approach requires the user to pre-specify the target standard error and the expected value for each performance measure alongside the outcome prevalence. We describe how the sample size formulae were derived and demonstrate their use in an example. Extension to time-to-event outcomes is also considered. In our examples, the minimum sample size required was lower than that required to precisely estimate the calibration slope, and we expect this would most often be the case. Our formulae, along with corresponding Python code and updated R, Stata and Python commands (pmvalsampsize), enable researchers to calculate the minimum sample size needed to precisely estimate threshold-based performance measures in an external evaluation study. These criteria should be used alongside previously published criteria to precisely estimate the calibration, discrimination, and net-benefit.
Longitudinal trajectories of health indicators using real world data
Older people with complex health needs are often excluded from clinical trials, primarily due to factors such as age, multimorbidity, and polypharmacy. However, they represent a significant portion of healthcare resource consumption and the use of newly authorised medications. Existing guidelines for identifying and treating this population often rely on using cross-sectional values and providing guidance on treating individual conditions rather than addressing the complexities of multimorbidity and treatment combinations. In this thesis, I propose applying novel approaches for identifying and characterising older people with complex health needs, using different health indicators and study designs on real world data. The definitions and cohorts established in this work have the potential to inform decisions for identifying, managing and treating older people with complex health needs. In the first project, I conducted a cross-sectional analysis to identify three cohorts of older people with high levels of frailty, polypharmacy, or unplanned hospital admissions. Patients in any of these cohorts had high comorbidity burden and preventive therapy use. Although there was considerable overlap between these cohorts, many patients only belonged to one of the three cohorts. This indicates that these health markers are intersectional and complementary to each other. Frailty and polypharmacy are cumulative conditions that take years to develop, making cross-sectional cohorts unable to describe their progression over time. In projects two and three, I modelled frailty and polypharmacy in older people over 4-5 years of follow-up. I identified subgroups with distinct frailty or polypharmacy trajectories, which demonstrated different association levels with the risk of mortality. Most of the population belonged to the low-steady/slow (healthy) subgroup. However, important subgroups emerging from these studies started from a seemingly healthy state, deteriorated rapidly over the study follow-up and had the highest mortality risks, indicating their need for more healthcare resources and monitoring. The subgroups were identified in a UK primary care database and then externally validated in two independent national and international databases. They demonstrated generalisability with good external validity, similar trajectories and clinical characteristics. Previous evidence reported that frailty and polypharmacy could start from middle age, and some of the identified subgroups of older people started from elevated or intermediate levels of frailty and polypharmacy. To understand these health markers’ progression from early on, I modelled polypharmacy over time in middle-aged people in the fourth project. I identified three subgroups with distinct polypharmacy trajectories and associated mortality risks. I found that those with the fastest polypharmacy trajectory had the highest mortality risk, followed by those starting at the highest polypharmacy baseline values. Those patients are likely to continue progressing and end up in one of the non-healthy subgroups at older age. My research demonstrated that monitoring trajectories of frailty and polypharmacy predicts mortality better than cross-sectional values. The identified subgroups were generalisable and had distinctive clinical characteristics. Future research can focus on further generalisability of the identified subgroups, and investigate how polypharmacy and frailty progress over longer periods, together and individually.
Stretch-induced microstructural evolution of electrospun polycaprolactone microfibers for biomedical applications
Abstract: The performance and degradation of polymeric medical yarns depend strongly on their microstructure, which can evolve significantly during fabrication. This work investigates and models how the microstructure of microfibrous electrospun (ES) filaments change during the critical post-processing step of uniaxial stretching. Specifically, we studied filaments designed for use in a knee ligament regeneration implant, made from biodegradable, semicrystalline polycaprolactone (PCL). Structural changes were characterized at both the fiber and molecular scales. Stretching led to fiber alignment, thinning, and coalescence, as revealed by micro-computed tomography (µCT) and scanning electron microscopy (SEM). At the molecular scale, the crystalline microarchitecture transformed profoundly, as shown by differential scanning calorimetry (DSC), 1D and 2D X-ray diffraction (XRD), and dynamic mechanical thermal analysis (DMTA). Based on these findings, we propose a conceptual model for stretch-induced microstructural evolution: at low strains, chain-folded crystals (CFC) fragment while amorphous chains extend; at higher strains, CFC unfold and recrystallize with extended chains into more thermodynamically stable chain-extended crystals (CEC) aligned with the stretch axis. This mechanism clarifies how uniaxial strain reorganizes semicrystalline domains in PCL, with important implications for thermomechanical and degradative properties relevant to implant performance. Understanding how microstructure responds to stretching enables the future development of more accurate simulations of complex fibrous materials under physiological conditions and informs the optimization of fabrication and design parameters for next-generation medical yarns.
Characterisation and modelling of continuous electrospun poly(ɛ- caprolactone) filaments for biological tissue repair.
This study investigates the mechanical behaviour of poly(ɛ-caprolactone) (PCL) continuous filaments produced by a novel electrospinning (ES) method. These filaments can be processed into woven or braided structures, showing great promises as scaffolds for ligament and tendon repair. Mechanical characterisation of the filaments using DMA and uniaxial tensile tests shows that the filament response is viscoelastic-viscoplastic. Filaments tested using bollard grips present an initially linear elastic response, followed by plastic yielding with two-stage hardening. The filaments are highly stretchable, reaching more than 1000% strain. The different deformation stages are correlated to the evolution of the micro-fibre network observed using SEM, involving the untangling, alignment and stretching of the fibres. A large deformation viscoelastic-viscoplastic model is proposed, which successfully captures the mechanical response of the filaments under non-monotonic loading conditions. Our study also highlights the sensitivity of the measured mechanical response to the type of mechanical grips, namely bollard or screw-side grips.
The experiences of clinical staff approaching families for organ donation consent: A systematic review and thematic synthesis of qualitative studies.
Healthcare professionals (HCPs) play an essential role in organ donation (OD) particularly when approaching families to discuss consent to OD. We synthesized the evidence on experiences of HCPs when approaching potential organ donor families. Fourteen electronic databases were searched to identify studies describing HCP experiences or associations between HCP experiences and consent rates. Methodological quality was assessed by independent reviewers using the Mixed Methods Appraisal Tool. Qualitative data were analysed using thematic synthesis, while quantitative data were summarized by narrative review. Ninety-two studies were included. HCP experiences were conceptualised as a paradox due to the challenges to negotiate the boundaries between life and death. Organisational and personal aspects broadly shape the experiences of professionals. Studies suggest that staff experiences can be improved by training and education, however, quantitative studies did not show a strong association between OD training and improved consent rates. The complexities of the family approach were evident in the variety of interactions between HCPs and the donor family, which may explain why there is no uniform approach across settings and countries. The review highlights the challenges faced by professionals when negotiating policy and practice and informs recommendations to support staff involved in the OD process worldwide.
The association between early-life gut microbiota and childhood respiratory diseases: a systematic review.
Data from animal models suggest a role of early-life gut microbiota in lung immune development, and in establishing susceptibility to respiratory infections and asthma in humans. This systematic review summarises the association between infant (ages 0-12 months) gut microbiota composition measured by genomic sequencing, and childhood (ages 0-18 years) respiratory diseases (ie, respiratory infections, wheezing, or asthma). Overall, there was evidence that low α-diversity and relative abundance of particular gut-commensal bacteria genera (Bifidobacterium, Faecalibacterium, Ruminococcus, and Roseburia) are associated with childhood respiratory diseases. However, results were inconsistent and studies had important limitations, including insufficient characterisation of bacterial taxa to species level, heterogeneous outcome definitions, residual confounding, and small sample sizes. Large longitudinal studies with stool sampling during the first month of life and shotgun metagenomic approaches to improve bacterial and fungal taxa resolution are needed. Standardising follow-up times and respiratory disease definitions and optimising causal statistical approaches might identify targets for primary prevention of childhood respiratory diseases.
Factors predicting poor glycemic control in the first two years of childhood onset type 1 diabetes in a cohort from East London, UK: Analyses using mixed effects fractional polynomial models.
BACKGROUND/OBJECTIVE: Poor early glycemic control in childhood onset type 1 diabetes (T1D) is associated with future risk of acute and chronic complications. Our aim was to identify the predictors of higher glycated hemoglobin (HbA1c) within 24 months of T1D diagnosis in children and adolescents. METHODS: Mixed effects models with fractional polynomials were used to analyze longitudinal data of patients <19 years of age, followed from T1D diagnosis for up to 2 years, at three diabetes clinics in East London, United Kingdom. RESULTS: A total of 2209 HbA1c observations were available for 356 patients (52.5% female; 64.4% non-white), followed from within 3 months of diagnosis during years 2005 to 2015, with a mean ± SD of 6.2 ± 2.5 HbA1c observations/participant. The mean age and HbA1c at diagnosis were 8.9 ± 4.3 years and 10.7% ±4.3% (or expressed as mmol/mol HbA1c mean ± SD 92.9 ± 23.10 mmol/mol) respectively. Over the 2 years following T1D diagnosis, HbA1c levels were mostly above the National Institute for Health, Care and Excellence (NICE), UK recommendations of 7.5% (<58 mmol/mol). Significant (P 9.5%, ie, >80 mmol/mol), clinic site, non-white ethnicity, and period (pre-year 2011) of diagnosis. Additionally in univariable analyses, frequency of clinic visits, HbA1c at diagnosis, and type of insulin treatment regimen showed association with poor glycemic control (P
Effect of early glycemic control on HbA1c tracking and development of vascular complications after 5 years of childhood onset type 1 diabetes: Systematic review and meta-analysis.
OBJECTIVE: A systematic review and meta-analysis was conducted to investigate if glycemic control measured by glycated hemoglobin (HbA1c) levels near diagnosis are predictive of future glycemic outcomes and vascular complications in childhood onset type 1 diabetes (T1D). METHODS: Evidence was gathered using electronic databases (MEDLINE, EMBASE, Web of Science, CINAHL, Scopus, and Cochrane Library up to February 2017) and snowballing techniques. Studies investigating the association between the exposure "early glycemic control" and main outcome: "tracking of early control" and secondary outcome: risk of future complications; in children and young people aged 0 to 19 years at baseline; were systematically double-reviewed, quality assessed, and outcome data extracted for synthesis and meta-analysis. FINDINGS: Five studies (N = 4227 participants) were eligible. HbA1c levels were sub-optimal throughout the study period but tended to stabilize in a "track" by 6 months after T1D diagnosis. The group with low HbA1c <53 mmol/mol (<7%) at baseline had lower long-term HbA1c levels than the higher HbA1c group. The estimated standardized mean difference between the sub groups showed a reduction of HbA1c levels on average by 1.6% (range -0.95% to -2.28%) from baseline. Only one study investigated the association between early glycemic control and development of vascular complications in childhood onset T1D. INTERPRETATIONS: Glycemic control after the first few months of childhood onset T1D, remains stable but sub-optimal for a decade. The low and high HbA1c levels at baseline seem to "track" in their respective tracks during the 10-year follow-up, however, the initial difference between groups narrows over time. PROSPERO: CRD42015024546 http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42015024546.
Predictors of glycemic control in the first year of diagnosis of childhood onset type 1 diabetes: A systematic review of quantitative evidence.
Early glycemic control is associated with reduced future vascular complications risk in type 1 diabetes (T1D). The aim of this study was to systematically review evidence on the predictors of glycemic control within 12 months of diagnosis of childhood onset T1D. Inclusion criteria for the electronic search were: interventional and observational studies that assessed and quantified an association between the predictor and glycemic control within 12 months of diagnosis of childhood onset T1D. A total of 17 915 articles were identified from 6 databases and 20 studies were finally included in the analysis. Harvest plots and narrative synthesis were used to summarize data from intervention (n = 0), prospective/retrospective cohort (n = 15), and cross-sectional (n = 5) studies. Significant predictors of poorer glycemic control 0 to 3 months after diagnosis were older age and female gender. Non-white ethnicity, diabetes autoantibody positivity, measures of deprivation, and non-private health insurance were potential predictors. Predictors of poorer glycemic control 4 to 12 months after diagnosis were: older age, non-white ethnicity, a single parent family, high hemoglobin A1c (HbA1c) levels at diagnosis, longer T1D duration, and non-intensive insulin therapy. Potential predictors included: family with health issues, clinical factors, and comorbidities at diagnosis. Most significant predictors of poor glycemic control within 12 months of diagnosis of childhood onset T1D are non-modifiable. These factors need to be recognized and addressed through individualized and multidisciplinary diabetes care. Further research is required to confirm the association of potential predictors with early glycemic control.
Determinants of sugar‐sweetened beverage consumption in young children: a systematic review
SummarySugar‐sweetened beverage (SSB) consumption is associated with adverse health outcomes. Improved understanding of the determinants will inform effective interventions to reduce SSB consumption. A total of 46,876 papers were identified through searching eight electronic databases. Evidence from intervention (n = 13), prospective (n = 6) and cross‐sectional (n = 25) studies on correlates/determinants of SSB consumption was quality assessed and synthesized. Twelve correlates/determinants were associated with higher SSB consumption (child's preference for SSBs, TV viewing/screen time and snack consumption; parents' lower socioeconomic status, lower age, SSB consumption, formula milk feeding, early introduction of solids, using food as rewards, parental‐perceived barriers, attending out‐of‐home care and living near a fast food/convenience store). Five correlates/determinants were associated with lower SSB consumption (parental positive modelling, parents' married/co‐habiting, school nutrition policy, staff skills and supermarket nearby). There was equivocal evidence for child's age and knowledge, parental knowledge, skills, rules/restrictions and home SSB availability. Eight intervention studies targeted multi‐level (child, parents, childcare/preschool setting) determinants; four were effective. Four intervention studies targeted parental determinants; two were effective. One (effective) intervention targeted the preschool environment. There is consistent evidence to support potentially modifiable correlates/determinants of SSB consumption in young children acting at parental (modelling), child (TV viewing) and environmental (school policy) levels.
Protocol for systematic review of evidence on the determinants and influence of early glycaemic control in childhood-onset type 1 diabetes.
BACKGROUND: Landmark studies in adult-onset type 1 diabetes (T1D) populations indicate that improved glycaemic control through use of intensive insulin therapy is strongly associated with reduced risk for the development of diabetes-related complications and mortality in later years. However, it is unclear whether these associations can be extrapolated to childhood-onset T1D, given the influence of other important biological and psychosocial determinants of glycaemic control, particularly during adolescence. The aims of the review are (1) to investigate the impact of early glycaemic control (within the first 2 years after diagnosis) on subsequent glycaemic trends and risk of complications during the life course of childhood-onset T1D and (2) to identify the predictors of early glycaemic control in children and young people (0-25 years). METHODS: The methods used in this study are systematic identification, review and mapping of quantitative (intervention and observational) and qualitative literature; assessing the effect and predictors of early glycaemic control in T1D (diagnosed ≤18 years) on risk or prevalence of later complications. An iterated search strategy, with no language or period restrictions, was applied to identify studies from six electronic databases. This will be supplemented by hand-searching (reference lists and contacting authors of studies meeting the inclusion criteria). Studies assessing glycaemic control within the first 2 years of diagnosis in children (at baseline) will be quality-assessed against predefined criteria and mapped descriptively to future health outcomes. Extracted data will be analysed and synthesised using narrative and forest plots or harvest plots for quantitative evidence and thematic analyses for qualitative studies. To get a deeper understanding of the predictors of early glycaemic control in reducing complications in childhood and adult life, we will integrate qualitative and quantitative evidence using mixed methods or parallel synthesis approach. DISCUSSION: These linked reviews will be the first to systematically investigate the effects of early glycaemic control and integrate both the quantitative and qualitative evidence on predictors of early glycaemic control in childhood-onset T1D in reducing future diabetes complications. This will help identify and map current research and inform development of effective future interventions. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42015024546.
Factors influencing obesogenic dietary intake in young children (0–6 years): systematic review of qualitative evidence
BackgroundObesogenic dietary intake is prevalent in young children and is associated with obesity and other adverse health outcomes in childhood and later in life.ObjectiveTo describe the barriers to and facilitators of obesogenic dietary intake in early childhood, in order to inform interventions and public health policies to prevent obesity.DesignSystematic review of qualitative literature on factors influencing obesogenic diets in children aged 0–6 years.Data sourcesMEDLINE, EMBASE, CINAHL, PsycINFO, Web of Knowledge, British Nursing Index, ASSIA and Sociological Abstracts.Review methodsQualitative studies meeting the inclusion criteria were synthesised. Data were analysed by creating a thematic framework, underpinned by the socioecological model, which included familiarisation of data across the studies, indexing, charting, mapping and interpretation.Results20 studies from the USA (10), Europe (6) and Australia (4) included the views of 1067 participants (901 parents/caregivers, 37 children, 87 teachers, 15 dieticians and 27 nursery staff). Study designs included focus groups (n=16), individual interviews (n=6) and ethnography (n=1) with some studies using more than one design. Despite wide differences in the study context and focus, several consistent themes emerged. Parental factors increasing young children's obesogenic diets were: negative parent/family/peer modelling, lack of knowledge, time constraints, using food as reward, affordability and concerns about child's health. Child preferences also increased intake. Environmental factors increasing intake include: availability, advertising, societal, cultural and preschool/childcare influences.ConclusionsFuture intervention strategies should aim to promote modelling of positive behaviours, create home and preschool environments that promote healthy diets, and simultaneously target factors at the family and preschool/childcare levels.Trial registration numberThis review is one of a series of systematic reviews on the determinants of obesogenic behaviours in young children, registered with the International Prospective Register for Systematic Reviews (PROSPERO), CRD42012002881.
Refining reporting guidelines using behaviour change theory
The lasting legacy of most medical research is the written account. When writing up their work, researchers often omit information that readers — including clinicians, reviewers, patients, and other researchers — need to fully understand, appraise, replicate, or apply the research. Reporting guidelines try to solve this problem. They are community-created recommendations of information to include when writing up research so that everybody can use it. The first reporting guideline was created almost 30 years ago, and many more have been created since. Most leading medical journals ask authors to adhere to reporting guidelines, yet adherence remains low in almost all medical fields. When authors do not adhere to reporting guidelines their work is less transparent, less valuable, contributes less to patient outcomes and has potential to inadvertently harm by distorting the evidence base. The aim of my thesis is to understand why authors do not adhere to reporting = guidelines when writing up medical research, and to address these reasons with the intention of increasing adherence in the future. I began my thesis with this clear aim but without a route to get there. My first step was a qualitative synthesis (chapter 3) of research exploring authors experiences of reporting guidelines, and I discovered authors’ adherence to reporting guidelines is influenced by features of the guidelines themselves, but also the system that surrounds them including the websites that disseminate them and the people and policies of the broader scholarly ecosystem. I probed this system further with a review of quantitative surveys and an evaluation of a key dissemination website (chapters 4 & 5). Given the complexity of the system and the complexity of the behaviour in question, I realised I would need a framework to help me make sense of them. I decided to use the Behaviour Change Wheel (chapter 6), a well established and evidenced framework for designing and defining complex behaviour change interventions. I led workshops and focus groups (chapters 7 & 8) to guide stakeholders through frameworks’ steps and, ultimately, ended up identifying 32 influences that needed to change, and 128 ideas of how to change them. These ideas were applicable to guideline developers, the EQUATOR Network, journals, publishers, funders, ethics committees, and institutions. I decided that redesigning reporting guidelines and EQUATOR’s website would be an effective, affordable, acceptable, and equitable way to realise many of the generated ideas. I defined 63 intervention components and managed to incorporate 46 into a prototype website that included a redesigned reporting guideline (the Standards for Reporting Qualitative Research) and the EQUATOR Network’s home page (chapter 9). I then explored authors experiences of using this prototype through in-depth interviews, observation, think aloud, and writing appraisals (chapter 10) and I identified 53 possible areas for improvement. My key outputs include a design blueprint for user-friendly reporting guideline resources, and an online platform for creating and hosting resources following this blueprint. This platform will benefit guideline developers who typically lack the money, time, and skills to create user friendly resources. A future feasibility study and parallel process evaluation will explore the acceptability and usability of this platform amongst authors submitting to journals, in preparation for a future evaluation to determine whether my redesign leads to more authors adhering to reporting guidelines successfully.
TGF-β is elevated in hyperuricemic individuals and mediates urate-induced hyperinflammatory phenotype in human mononuclear cells.
BACKGROUND: Soluble urate leads to a pro-inflammatory phenotype in human monocytes characterized by increased production of IL-1β and downregulation of IL-1 receptor antagonist, the mechanism of which remains to be fully elucidated. Previous transcriptomic data identified differential expression of genes in the transforming growth factor (TGF)-β pathway in monocytes exposed to urate in vitro. In this study, we explore the role of TGF-β in urate-induced hyperinflammation in peripheral blood mononuclear cells (PBMCs). METHODS: TGF-β mRNA in unstimulated PBMCs and protein levels in plasma were measured in individuals with normouricemia, hyperuricemia and gout. For in vitro validation, PBMCs of healthy volunteers were isolated and treated with a dose ranging concentration of urate for assessment of mRNA and pSMAD2. Urate and TGF-β priming experiments were performed with three inhibitors of TGF-β signalling: SB-505124, 5Z-7-oxozeaenol and a blocking antibody against TGF-β receptor II. RESULTS: TGF-β mRNA levels were elevated in gout patients compared to healthy controls. TGF-β-LAP levels in serum were significantly higher in individuals with hyperuricemia compared to controls. In both cases, TGF-β correlated positively to serum urate levels. In vitro, urate exposure of PBMCs did not directly induce TGF-β but did enhance SMAD2 phosphorylation. The urate-induced pro-inflammatory phenotype of monocytes was partly reversed by blocking TGF-β. CONCLUSIONS: TGF-β is elevated in individuals with hyperuricemia and correlated to serum urate concentrations. In addition, the urate-induced pro-inflammatory phenotype in human monocytes is mediated by TGF-β signalling. Future studies are warranted to explore the intracellular pathways involved and to assess the clinical significance of urate-TGF-β relation.
Early radiological outcomes of a fully porous bridging collar in lower-limb endoprosthetic reconstructions: a case-matched retrospective series to assess osseointegration.
BACKGROUND: Limb-salvage surgery involving the utilization of endoprosthetic replacements is commonly employed following segmental bone resection for primary and secondary bone tumors. This study aimed to evaluate whether a fully porous bridging collar promotes early osseous integration in endoprosthetic replacements. METHODS: We undertook a retrospective review of all lower-limb endoprostheses utilizing a fully porous endosteal bridging collar design. We matched this cohort with a conventional extra-osteal non-porous fully hydroxyapatite-coated grooved collar cohort according to surgical indication, implant type, resection length, age, and follow-up time. At 6, 12, and 24 months post-implantation, radiographs were assessed for the number of cortices with or without osseointegration on orthogonal radiographs. Each radiograph was scored on a scale of -4 to + 4 for the number of cortices bridging the ongrowth between the bone and the collar of the prosthesis. Implant survival was estimated using the Kaplan-Meier method, and the mean number of osseointegrated cortices at each time point between the collar designs was compared using a paired t-test. RESULTS: Ninety patients were retrospectively identified and analyzed. After exclusion, 40 patients with porous bridging collars matched with 40 patients with conventional extra-osteal non-porous collars were included in the study (n = 80). The mean age was 63.4 years (range 16-91 years); there were 37 males and 43 females. The groups showed no difference in implant survival (P = 0.54). The mean number of cortices with radiographic ongrowth for the porous bridging collar and non-porous collar groups was 2.1 and 0.3, respectively, at 6-month (P