The influence of frailty on outcomes for older adults admitted to hospital with benign biliary disease: a single-centre, observational cohort study.

INTRODUCTION: The prevalence and complications of biliary disease increase with age. Frailty has been associated with adverse outcomes in the hospital setting. We describe the prevalence of frailty in older patients hospitalised with benign biliary disease and its association with duration of hospital stay, and 90-day and 1-year mortality. METHODS: We performed a retrospective cohort study of patients aged 75 years and over admitted with acute biliary disease between 17 September 2014 and 20 March 2017. Clinical Frailty Scale (CFS) score was recorded on admission. RESULTS: We included 200 patients with a median age of 82 (75-99) years, 60% were female; 154 (77%) were independent for personal activities of daily living (ADLs) and 99 (49.5%) for instrumental ADLs. Cholecystitis was the most common diagnosis (43%) followed by cholangitis (36%) and pancreatitis (21%). Ninety-nine patients were non frail (NF; CFS 1-4) and 101 were frail (F; CFS 5-9). Some 104 patients received medical treatment only. Surgery was more common in NF patients (11% vs F 2%), percutaneous drainage more frequently performed in F patients (15% vs NF 5%) and endoscopic cholangiopancreatography was similar in both groups (F 32% vs NF 31%). Frailty was associated with worse clinical outcomes in F vs NF: functional deconditioning (34% vs 11%), increased care level (19% vs 3%), length of stay (12 vs 7 days), 90-day mortality (8% vs 3%) and 1-year mortality (48% vs 24%). CONCLUSIONS: Half of patients in our cohort were frail and spent longer in hospital, were less likely to undergo surgery and were less likely to remain alive at 1 year after discharge.

No exponential rise in revision knee replacement surgery over the past 15 years: an analysis from the National Joint Registry.

OBJECTIVE: To investigate trends in the incidence rate and the main indication for revision knee replacement (rKR) over the past 15 years in the UK. METHOD: Repeated national cross-sectional study from 2006 to 2020 using data from the National Joint Registry (NJR). Crude incidence rates were calculated using population statistics from the Office for National Statistics. RESULTS: Annual total counts of rKR increased from 2,743 procedures in 2006 to 6,819 procedures in 2019 (149% increase). The incidence rate of rKR increased from 6.3 per 100,000 adults in 2006 (95% CI 6.1 to 6.5) to 14 per 100,000 adults in 2019 (95% CI 14 to 14) (122% increase). Annual increases in the incidence rate of rKR became smaller over the study period. There was a 43.6% reduction in total rKR procedures in 2020 (during the Covid-19 pandemic) compared to 2019. Aseptic loosening was the most frequent indication for rKR overall (20.7% procedures). rKR for aseptic loosening peaked in 2012 and subsequently decreased. rKR for infection increased incrementally over the study period to become the most frequent indication in 2019 (2.7 per 100,000 adults [95% CI 2.6 to 2.9]). Infection accounted for 17.1% first linked rKR, 36.5% second linked rKR and 49.4% third or more linked rKR from 2014 to 2019. CONCLUSIONS: Recent trends suggest slowing of the rate of increase in the incidence of rKR. Infection is now the most common indication for rKR, following recent decreases in rKR for aseptic loosening. Infection was prevalent in re-revision KR procedures.

Evaluation of a method to measure fluorescent cell burden in complex culture systems.

Purpose. This work introduces and evaluates a method for accurate in-vitro measurement of fluorescent cell burden in complex 3D-culture conditions.Methods.The Fluorescent Cell Burden (FCB) method was developed to analyze the burden of 4T1 mCherry-expressing cells grown in an organotypic co-culture model of brain metastasis using 400µm rat brain slices. As a first step, representative simulated image-data accurately reflecting the 4T1 experimental data, but with known ground truth burden, were created. The FCB method was then developed in the CellProfiler software to measure the integrated intensity and area of the colonies in the simulated image data. Parameters in the pipeline were varied to span the experimentally observed range (e.g. of cell colony size) and the result compared with simulation ground truth to evaluate and optimize FCB performance. The optimized CellProfiler pipeline was then applied to the original 4T1 tumor cell images to determine colony growth with time, and re-applied with upper and lower bound parameters to determine uncertainty estimates.Results.The FCB method measured integrated intensity across 10 simulated images with an accuracy of 99.23% ± 0.75%. When colony density was increased by increasing colony number to 450, 600, and 750, the FCB measurement was 98.68%, 100.9%, 97.6% and 113.5% of the true value respectively. For the increasing number of cells plated on the rat brain slices, the integrated intensity increased nearly linearly with cell count except for at high cell counts, where it is hypothesized that shadowing from clumped cells causes a sub-linear relationship.Conclusion. The FCB method accurately measured an integrated fluorescent light intensity to within 5% of ground truth for a wide range of simulated image data spanning the range of observed variability in experimental data. The method is readily customizable to in-vitro studies requiring estimation of fluorescent tumor cell burden.

The feasibility of home monitoring of young people with cystic fibrosis: Results from CLIMB-CF.

BACKGROUND: CF is traditionally assessed in clinic. It is unclear if home monitoring of young people with CF is feasible or acceptable. The COVID-19 pandemic has made home monitoring more of a necessity. We report the results of CLIMB-CF, exploring home monitoring's feasibility and potential obstacles. METHODS: We designed a mobile app and enrolled participants with CF aged 2-17 years and their parents for six months. They were asked to complete a variety of measures either daily or twice a week. During the study, participants and their parents completed questionnaires exploring depression, anxiety and quality of life. At the end of the study parents and participants completed acceptability questionnaires. RESULTS: 148 participants were recruited, 4 withdrew prior to starting the study. 82 participants were female with median (IQR) age 7.9 (5.2-12 years). Median data completeness was 40.1% (13.6-69.9%) for the whole cohort; when assessed by age participants aged ≥ 12 years contributed significantly less (15.6% [9.8-30%]). Data completeness decreased over time. There was no significant difference between parental depression and anxiety scores at the start and the end of the study nor in CFQ-R respiratory domain scores for participants ≥ 14 years. The majority of participants did not feel the introduction of home monitoring impacted their daily lives. CONCLUSIONS: Most participants felt home monitoring did not negatively impact their lives and it did not increase depression, anxiety or decrease quality of life. However, uptake was variable, and not well sustained. The teenage years pose a particular challenge and further work is required.

Revision knee replacement surgery in the NHS: A BASK surgical practice guideline.

BACKGROUND: Revision knee replacement (KR) is both challenging for the surgical team and expensive for the healthcare provider. Limited high quality evidence is available to guide decision-making. AIM: To provide guidelines for surgeons and units delivering revision KR services. METHODS: A formal consensus process was followed by BASK's Revision Knee Working Group, which included surgeons from England, Wales, Scotland and Northern Ireland. This was supported by analysis of National Joint Registry data. RESULTS: There are a large number of surgeons operating at NHS sites who undertake a small number of revision KR procedures. To optimise patient outcomes and deliver cost-effective care high-volume revision knee surgeons working at high volume centres should undertake revision KR. This document outlines practice guidelines for units providing a revision KR service and sets out: The current landscape of revision KR in England, Wales and Northern Ireland. Service organisation within a network model. The necessary infrastructure required to provide a sustainable revision service. Outcome metrics and auditable standards. Financial mechanisms to support this service model. CONCLUSIONS: Revision KR patients being treated in the NHS should be provided with the best care available. This report sets out a framework to both guide and support revision KR surgeons and centres to achieve this aim.

Increased care at discharge from COVID-19: The association between pre-admission frailty and increased care needs after hospital discharge; a multicentre European observational cohort study.

BACKGROUND: The COVID-19 pandemic has placed significant pressure on health and social care. Survivors of COVID-19 may be left with substantial functional deficits requiring ongoing care. We aimed to determine whether pre-admission frailty was associated with increased care needs at discharge for patients admitted to hospital with COVID-19. METHODS: Patients were included if aged over 18 years old and admitted to hospital with COVID-19 between 27 February and 10 June 2020. The Clinical Frailty Scale (CFS) was used to assess pre-admission frailty status. Admission and discharge care levels were recorded. Data were analysed using a mixed-effects logistic regression adjusted for age, sex, smoking status, comorbidities, and admission CRP as a marker of severity of disease. RESULTS: Thirteen hospitals included patients: 1671 patients were screened, and 840 were excluded including, 521 patients who died before discharge (31.1%). Of the 831 patients who were discharged, the median age was 71 years (IQR, 58-81 years) and 369 (44.4%) were women. The median length of hospital stay was 12 days (IQR 6-24). Using the CFS, 438 (47.0%) were living with frailty (≥ CFS 5), and 193 (23.2%) required an increase in the level of care provided. Multivariable analysis showed that frailty was associated with an increase in care needs compared to patients without frailty (CFS 1-3). The adjusted odds ratios (aOR) were as follows: CFS 4, 1.99 (0.97-4.11); CFS 5, 3.77 (1.94-7.32); CFS 6, 4.04 (2.09-7.82); CFS 7, 2.16 (1.12-4.20); and CFS 8, 3.19 (1.06-9.56). CONCLUSIONS: Around a quarter of patients admitted with COVID-19 had increased care needs at discharge. Pre-admission frailty was strongly associated with the need for an increased level of care at discharge. Our results have implications for service planning and public health policy as well as a person's functional outcome, suggesting that frailty screening should be utilised for predictive modelling and early individualised discharge planning.

Provision of revision knee surgery and calculation of the effect of a network service reconfiguration: An analysis from the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man.

BACKGROUND: Revision knee replacement (KR) is technically challenging, expensive, and outcomes can be poor. It is well established that increasing surgeon and unit volumes results in improved outcomes and cost-effectiveness for complex procedures. The aim of this study was to 1) describe the current provision of revision KR in England, Wales and Northern Ireland at the individual surgeon and unit level and 2) investigate the effect on workload of case distribution in a network model. METHODS: Current practice was mapped using NJR summary statistics containing all revision KR procedures performed over a three-year period (2016-2018). Units were identified as revision centres based on threshold volumes. Units undertaking <20 revisions per year were classified as Primary Arthroplasty Units (PAUs) in calculations on the effect of workload centralisation. RESULTS: Revision KR was performed by 1353 surgeons at 232 NHS sites. The majority of surgeons and units were low-volume; >1000 surgeons performed <7 and 125 sites performed <20 procedures per year. Reallocation of work from these 125 PAUs (1235 cases, 21% of total workload) to a network model with even redistribution of cases between centres undertaking revision surgery would result in an additional average annual case increase of 11 per unit per year (range six to 14). CONCLUSIONS: Revision KR workload re-allocation would lift all revision centres above a 30 per year threshold and would appear to be a manageable increase in workload for specialist revision KR centres. Case complexity and local referral agreements will significantly affect the real increase in workload; these factors were not incorporated here.

The use of patient-reported outcome measures to guide referral for hip and knee arthroplasty.

AIMS: To assess how the cost-effectiveness of total hip arthroplasty (THA) and total knee arthroplasty (TKA) varies with age, sex, and preoperative Oxford Hip or Knee Score (OHS/OKS); and to identify the patient groups for whom THA/TKA is cost-effective. METHODS: We conducted a cost-effectiveness analysis using a Markov model from a United Kingdom NHS perspective, informed by published analyses of patient-level data. We assessed the cost-effectiveness of THA and TKA in adults with hip or knee osteoarthritis compared with having no arthroplasty surgery during the ten-year time horizon. RESULTS: THA and TKA cost < £7,000 per quality-adjusted life-year (QALY) gained at all preoperative scores below the absolute referral thresholds calculated previously (40 for OHS and 41 for OKS). Furthermore, THA cost < £20,000/QALY for patients with OHS of ≤ 45, while TKA was cost-effective for patients with OKS of ≤ 43, since the small improvements in quality of life outweighed the cost of surgery and any subsequent revisions. Probabilistic and one-way sensitivity analyses demonstrated that there is little uncertainty around the conclusions. CONCLUSION: If society is willing to pay £20,000 per QALY gained, THA and TKA are cost-effective for nearly all patients who currently undergo surgery, including all patients at and above our calculated absolute referral thresholds. Cite this article: Bone Joint J 2020;102-B(7):950-958.

Alternative and complementary therapies in osteoarthritis and cartilage repair.

Osteoarthritis (OA) is the most common joint condition and, with a burgeoning ageing population, is due to increase in prevalence. Beyond conventional medical and surgical interventions, there are an increasing number of 'alternative' therapies. These alternative therapies may have a limited evidence base and, for this reason, are often only afforded brief reference (or completely excluded) from current OA guidelines. Thus, the aim of this review was to synthesize the current evidence regarding autologous chondrocyte implantation (ACI), mesenchymal stem cell (MSC) therapy, platelet-rich plasma (PRP), vitamin D and other alternative therapies. The majority of studies were in knee OA or chondral defects. Matrix-assisted ACI has demonstrated exceedingly limited, symptomatic improvements in the treatment of cartilage defects of the knee and is not supported for the treatment of knee OA. There is some evidence to suggest symptomatic improvement with MSC injection in knee OA, with the suggestion of minimal structural improvement demonstrated on MRI and there are positive signals that PRP may also lead to symptomatic improvement, though variation in preparation makes inter-study comparison difficult. There is variability in findings with vitamin D supplementation in OA, and the only recommendation which can be made, at this time, is for replacement when vitamin D is deplete. Other alternative therapies reviewed have some evidence (though from small, poor-quality studies) to support improvement in symptoms and again there is often a wide variation in dosage and regimens. For all these therapeutic modalities, although controlled studies have been undertaken to evaluate effectiveness in OA, these have often been of small size, limited statistical power, uncertain blindness and using various methodologies. These deficiencies must leave the question as to whether they have been validated as effective therapies in OA (or chondral defects). The conclusions of this review are that all alternative interventions definitely require clinical trials with robust methodology, to assess their efficacy and safety in the treatment of OA beyond contextual and placebo effects.

Radiation Dosimetry in 177Lu-PSMA-617 Therapy Using a Single Posttreatment SPECT/CT Scan: A Novel Methodology to Generate Time- and Tissue-Specific Dose Factors.

Calculation of radiation dosimetry in targeted nuclear medicine therapies is traditionally resource-intensive, requiring multiple posttherapy SPECT acquisitions. An alternative approach is to take advantage of existing pharmacokinetic data from these smaller cohorts to enable dose computation from a single posttreatment scan in a manner that may be applied to a much broader patient population. Methods: In this work, a technical description of simplified dose estimation is presented and applied to the assessment of 177Lu-prostate-specific membrane antigen (PSMA)-617 therapy for metastatic prostate cancer. By normalizing existing time-activity curves to a single measurement time, it is possible to calculate a mean and range of time-integrated activity values that relate to absorbed radiation dose. To assist with accurate pharmacokinetic modeling of the training cohort, a method for contour-guided image registration was developed. Results: Tissue-specific dose conversion factors for common posttreatment imaging times are reported along with a characterization of added uncertainty in comparison to a traditional serial imaging protocol. Single-time-point dose factors for tumor were determined to be 11.0, 12.1, 13.6, and 15.2 Gy per MBq/mL at image times of 24, 48, 72, and 96 h, respectively. For normal tissues, parotid gland factors were 6.7, 9.4, 13.3, and 19.3 Gy per MBq/mL at those times, and kidneys were 7.1, 10.3, 15.0, and 22.0 Gy per MBq/mL. Tumor dose estimates were most accurate using delayed scanning at times beyond 72 h. Dose to healthy tissues is best characterized by scanning patients in the first 2 d of treatment because of the larger degree of tracer clearance in this early phase. Conclusion: This work demonstrates a means for efficient dose estimation in 177Lu-PSMA-617 therapy. By providing methods to simplify and potentially automate radiation dosimetry, we hope to accelerate the understanding of radiobiology and development of dose-response models in this unique therapeutic context.

Arthroscopic meniscal surgery: a national society treatment guideline and consensus statement.

AIMS: The aim of the British Association for Surgery of the Knee (BASK) Meniscal Consensus Project was to develop an evidence-based treatment guideline for patients with meniscal lesions of the knee. MATERIALS AND METHODS: A formal consensus process was undertaken applying nominal group, Delphi, and appropriateness methods. Consensus was first reached on the terminology relating to the definition, investigation, and classification of meniscal lesions. A series of simulated clinical scenarios was then created and the appropriateness of arthroscopic meniscal surgery or nonoperative treatment in each scenario was rated by the group. The process was informed throughout by the latest published, and previously unpublished, clinical and epidemiological evidence. Scenarios were then grouped together based upon the similarity of clinical features and ratings to form the guideline for treatment. Feedback on the draft guideline was sought from the entire membership of BASK before final revisions and approval by the consensus group. RESULTS: A total of 45 simulated clinical scenarios were refined to five common clinical presentations and six corresponding treatment recommendations. The final guideline stratifies patients based upon a new, standardized classification of symptoms, signs, radiological findings, duration of symptoms, and previous treatment. CONCLUSION: The 2018 BASK Arthroscopic Meniscal Surgery Treatment Guidance will facilitate the consistent identification and treatment of patients with meniscal lesions. It is hoped that this guidance will be adopted nationally by surgeons and help inform healthcare commissioning guidance. Validation in clinical practice is now required and several areas of uncertainty in relation to treatment should be a priority for future high-quality prospective studies. Cite this article: Bone Joint J 2019;101-B:652-659.

Impact of a national enhanced recovery after surgery programme on patient outcomes of primary total knee replacement: an interrupted time series analysis from "The National Joint Registry of England, Wales, Northern Ireland and the Isle of Man".

OBJECTIVE: We aimed to test whether a national Enhanced Recovery After Surgery (ERAS) Programme in total knee replacement (TKR) had an impact on patient outcomes. DESIGN: Natural-experiment (April 2008-December 2016). Interrupted time-series regression assessed impact on trends before-during-after ERAS implementation. SETTING: Primary operations from the UK National Joint Registry (NJR) were linked with Hospital Episode Statistics (HES) data which contains inpatient episodes undertaken in National Health Service (NHS) trusts in England, and Patient Reported Outcome Measures (PROMs). PARTICIPANTS: Patients undergoing primary planned TKR aged ≥18 years. INTERVENTION: ERAS implementation (April 2009-March 2011). OUTCOMES: Regression coefficients of monthly means of Length of stay (LOS), bed day costs, change in Oxford knee scores (OKS) 6-months after surgery, complications (at 6 months), and rates of revision surgeries (at 5 years). RESULTS: 486,579 primary TKRs were identified. Overall LOS and bed-day costs decreased from 5.8 days to 3.7 and from £7607 to £5276, from April 2008 to December 2016. Oxford knee score (OKS) change improved from 15.1 points in April 2008 to 17.1 points in December 2016. Complications decreased from 4.1 % in April 2008 to 1.7 % in March 2016. 5-year revision rates remained stable at 4.8 per 1000 implants years in April 2008 and December 2011. After ERAS, declining trends in LOS and bed costs slowed down; OKS improved, complications remained stable, and revisions slightly increased. CONCLUSIONS: Different secular trends in outcomes for patients having TKR have been observed over the last decade. Although patient outcomes are better than a decade ago ERAS did not improve them at national level.

Rates of knee arthroplasty within one-year of undergoing arthroscopic partial meniscectomy in England: temporal trends, regional and age-group variation in conversion rates.

OBJECTIVE: The aim of this study was to determine the proportion of patients undergoing arthroscopic partial meniscectomy (APM) then subsequently receiving a knee arthroplasty within one or two years, with focus on patients over the age of 60 years and regional variation. METHODS: Patients undergoing APM in England over 20-years (01-April-1997 to 31-March 2017) were identified in the national Hospital Episode Statistics (HES). The proportion of patients undergoing arthroplasty in the same knee within one or two years of APM was determined and trends were analysed over time nationally and by NHS Clinical Commissioning Group (CCG) region. RESULTS: 806,195 APM patients were eligible for analysis with at least one-year of follow up and 746,630 with two-years. The odds of arthroplasty conversion within one year increased over the study period (odds ratio [OR] 3.10 within 1-year in 2014 vs 2000; 95% confidence interval [CI] 2.75-3.50). For patients undergoing APM aged 60 years or older in 2015-16, 9.9% (1689/17,043; 95% CI 9.5-10.4) underwent arthroplasty within 1-year and, in 2014-15, 16.6% (3100/18,734; 95% CI 16.0-17.1) underwent arthroplasty within 2-years. There was greater than 10-fold variation by CCG. CONCLUSIONS: Over the study period, the proportion of patients undergoing arthroplasty within one-year of APM increased. In 2015-16, of patients aged 60 years or older who underwent APM, 10% subsequently underwent knee arthroplasty within one year (17% within two years in 2014-15) and there was a high level of regional variation in this outcome. The development and adoption of national treatment guidance is recommended to improve and standardise treatment selection.

Draft Genome Sequences of the Nitrate-Dependent Iron-Oxidizing Proteobacteria Acidovorax sp. Strain BoFeN1 and Paracoccus pantotrophus Strain KS1.

The draft genomes of the nitrate-dependent iron-oxidizing bacteria Acidovorax sp. strain BoFeN1 and Paracoccus pantotrophus strain KS1 are presented. These genomes supply supporting data to investigations of the mechanisms underlying this anaerobic form of microbial biogeochemical iron cycling.

National consensus on the definition, investigation, and classification of meniscal lesions of the knee.

BACKGROUND: The aim of this study was to deliver standardised terminology for the identification and stratification of patients with meniscal lesions of the knee. METHODS: A national group of expert surgeons was convened by the British Association for Surgery of the Knee (BASK) and a formal consensus process was undertaken following a validated methodology. A combination of nominal group techniques and an iterative Delphi process was used to develop and refine relevant definitions. Where appropriate, definitions were placed into categories to facilitate use in clinical practice and guideline development. RESULTS: A degenerative meniscus develops progressively with degradation of meniscal tissue and this may be revealed by intra-meniscal high signal on magnetic resonance imaging (MRI). A meniscal tear was defined as a defect or split in the meniscocapsular complex, which can occur in a degenerative or non-degenerative meniscus. Degenerative meniscal lesions (high signal or tear) are frequent in the general population and are often incidental findings on knee MRI. Symptoms were defined and classified into three groups: (1) strongly suggestive of a treatable meniscal lesion, (2) potentially suggestive of a treatable meniscal lesion, (3) osteoarthritic. A strategy for radiological imaging (radiograph ±â€¯MRI) was agreed for the investigation of the patients with a possible meniscal tear. Meniscal lesions and tear patterns on MRI imaging were defined and classified with reference to potential treatability: (1) target, (2) possible target, (3) no target. CONCLUSIONS: The agreed terminology will enable patients with meniscal lesions to be identified and stratified consistently in clinical practice, research and guideline development.

Topical propranolol for infantile haemangiomas: a systematic review.

Infantile haemangiomas are the most common tumour of infancy. Whilst the majority are left untreated to involute spontaneously, residual skin changes commonly occur, particularly in superficial haemangiomas. The current first-line treatment for problematic lesions is oral propranolol; however due to the risk of systemic adverse effects, the use of off-label topical preparations has recently been investigated. Our systematic review was conducted in accordance with PRISMA guidelines. Four databases were searched to identify original articles evaluating the use of topical propranolol as the primary therapy for infantile haemangiomas. Twelve articles with a total of 597 patients and 632 haemangiomas were included. Three topical propranolol preparations were used, creams, ointments and gels and were all prepared by local pharmaceutical laboratories. The concentration of propranolol ranged from 0.5% to 5%. Treatment duration ranged from two weeks to 16.5 months. Overall, 90% of lesions improved following the initiation of topical propranolol. A good or excellent response, defined as a reduction in the size of at least 50%, was seen in 59% of lesions. Earlier initiation of treatment (less than 3 months of age) was associated with improved outcomes. No systemic adverse effects were reported. Minor local reactions were seen in 1.3% of patients. Topical propranolol is safer than oral propranolol, though may be less effective. Topical propranolol may be more suitable for patients with small, superficial haemangiomas at risk of cosmetic sequelae, where the cosmetic or symptomatic impact does not warrant oral propranolol treatment.

Development and validation of a clinical prediction model for patient-reported pain and function after primary total knee replacement surgery.

To develop and validate a clinical prediction model of patient-reported pain and function after undergoing total knee replacement (TKR). We used data of 1,649 patients from the Knee Arthroplasty Trial who received primary TKR across 34 centres in the UK. The external validation included 595 patients from Southampton University Hospital, and Nuffield Orthopaedic Centre (Oxford). The outcome was the Oxford Knee Score (OKS) 12-month after TKR. Pre-operative predictors including patient characteristics and clinical factors were considered. Bootstrap backward linear regression analysis was used. Low pre-operative OKS, living in poor areas, high body mass index, and patient-reported anxiety or depression were associated with worse outcome. The clinical factors associated with worse outcome were worse pre-operative physical status, presence of other conditions affecting mobility and previous knee arthroscopy. Presence of fixed flexion deformity and an absent or damaged pre-operative anterior cruciate ligament (compared with intact) were associated with better outcome. Discrimination and calibration statistics were satisfactory. External validation predicted 21.1% of the variance of outcome. This is the first clinical prediction model for predicting self-reported pain and function 12 months after TKR to be externally validated. It will help to inform to patients regarding expectations of the outcome after knee replacement surgery.