Aims. This aim of this study was to analyze the detection rate of rare pathogens in bone and joint infections (BJIs) using metagenomic next-generation sequencing (mNGS), and the impact of mNGS on clinical diagnosis and treatment. Methods. A retrospective analysis was conducted on 235 patients with BJIs who were treated at our hospital between January 2015 and December 2021. Patients were divided into the no-mNGS group (microbial culture only) and the mNGS group (mNGS testing and microbial culture) based on whether mNGS testing was used or not. Results. A total of 147 patients were included in the no-mNGS group and 88 in the mNGS group. The mNGS group had a higher detection rate of rare pathogens than the no-mNGS group (21.6% vs 10.2%, p = 0.016). However, the mNGS group had lower rates of antibiotic-related complications, shorter hospital stays, and higher infection control rates compared with the no-mNGS group (p = 0.017, p = 0.003, and p = 0.028, respectively), while there was no significant difference in the duration of antibiotic use (p = 0.957). In culture-negative cases, the mNGS group had lower rates of antibiotic-related complications, shorter hospital stays, and a higher infection control rate than the no-mNGS group (p = 0.036, p = 0.033, p = 0.022, respectively), while there was no significant difference in the duration of antibiotic use (p = 0.748). Conclusion. mNGS improves detection of rare pathogens in BJIs. mNGS testing reduces antibiotic-related complications, shortens hospital stay and antibiotic use duration, and improves treatment success rate, benefits which are particularly evident in culture-negative cases. Cite this article: Bone Joint Res 2024;13(8):401–410

Aims. Precise implant positioning, tailored to individual spinopelvic biomechanics and phenotype, is paramount for stability in total hip arthroplasty (THA). Despite a few studies on instability prediction, there is a notable gap in research utilizing artificial intelligence (AI). The objective of our pilot study was to evaluate the feasibility of developing an AI algorithm tailored to individual spinopelvic mechanics and patient phenotype for predicting impingement. Methods. This international, multicentre prospective cohort study across two centres encompassed 157 adults undergoing primary robotic arm-assisted THA. Impingement during specific flexion and extension stances was identified using the virtual range of motion (ROM) tool of the robotic software. The primary AI model, the Light Gradient-Boosting Machine (LGBM), used tabular data to predict impingement presence, direction (flexion or extension), and type. A secondary model integrating tabular data with plain anteroposterior pelvis radiographs was evaluated to assess for any potential enhancement in prediction accuracy. Results. We identified nine predictors from an analysis of baseline spinopelvic characteristics and surgical planning parameters. Using fivefold cross-validation, the LGBM achieved 70.2% impingement prediction accuracy. With impingement data, the LGBM estimated direction with 85% accuracy, while the support vector machine (SVM) determined impingement type with 72.9% accuracy. After integrating imaging data with a multilayer perceptron (tabular) and a convolutional neural network (radiograph), the LGBM’s prediction was 68.1%. Both combined and LGBM-only had similar impingement direction prediction rates (around 84.5%). Conclusion. This study is a pioneering effort in leveraging AI for impingement prediction in THA, utilizing a comprehensive, real-world clinical dataset. Our machine-learning algorithm demonstrated promising accuracy in predicting impingement, its type, and direction. While the addition of imaging data to our deep-learning algorithm did not boost accuracy, the potential for refined annotations, such as landmark markings, offers avenues for future enhancement. Prior to clinical integration, external validation and larger-scale testing of this algorithm are essential. Cite this article: Bone Jt Open 2024;5(8):671–680

Aims. The escalating demand for medical resources to address spinal diseases as society ages is an issue that requires careful evaluation. However, few studies have examined trends in spinal surgery, especially unscheduled hospitalizations or surgeries performed after hours, through large databases. Our study aimed to determine national trends in the number of spine surgeries in Japan. We also aimed to identify trends in after-hours surgeries and unscheduled hospitalizations and their impact on complications and costs. Methods. We retrospectively investigated data extracted from the Diagnosis Procedure Combination database, a representative inpatient database in Japan. The data from April 2010 to March 2020 were used for this study. We included all patients who had undergone any combination of laminectomy, laminoplasty, discectomy, and/or spinal arthrodesis. Results. This investigation included 739,474 spinal surgeries and 739,215 hospitalizations in Japan. There was an average annual increase of 4.6% in the number of spinal surgeries. Scheduled hospitalizations increased by 3.7% per year while unscheduled hospitalizations increased by 11.8% per year. In-hours surgeries increased by 4.5% per year while after-hours surgeries increased by 9.9% per year. Complication rates and costs increased for both after-hours surgery and unscheduled hospitalizations, in comparison to their respective counterparts of in-hours surgery and scheduled hospitalizations. Conclusion. This study provides important insights for those interested in improving spine care in an ageing society. The swift surge in after-hours spinal surgeries and unscheduled hospitalizations highlights that the medical needs of an increasing number of patients due to an ageing society are outpacing the capacity of existing medical resources. Cite this article: Bone Jt Open 2024;5(8):662–670

Aims. The aims of this study were to describe the epidemiology of metacarpal shaft fractures (MSFs), assess variation in treatment and complications following standard care, document hospital resource use, and explore factors associated with treatment modality. Methods. A multicentre, cross-sectional retrospective study of MSFs at six centres in the UK. We collected and analyzed healthcare records, operative notes, and radiographs of adults presenting within ten days of a MSF affecting the second to fifth metacarpal between 1 August 2016 and 31 July 2017. Total emergency department (ED) attendances were used to estimate prevalence. Results. A total of 793 patients (75% male, 25% female) with 897 MSFs were included, comprising 0.1% of 837,212 ED attendances. The annual incidence of MSF was 40 per 100,000. The median age was 27 years (IQR 21 to 41); the highest incidence was in men aged 16 to 24 years. Transverse fractures were the most common. Over 80% of all fractures were treated non-surgically, with variation across centres. Overall, 12 types of non-surgical and six types of surgical treatment were used. Fracture pattern, complexity, displacement, and age determined choice of treatment. Patients who were treated surgically required more radiographs and longer radiological and outpatient follow-up, and were more likely to be referred for therapy. Complications occurred in 5% of patients (39/793). Most patients attended planned follow-up, with 20% (160/783) failing to attend at least one or more clinic appointments. Conclusion. MSFs are common hand injuries among young, working (economically active) men, but there is considerable heterogeneity in treatment, rehabilitation, and resource use. They are a burden on healthcare resources and society, thus further research is needed to optimize treatment. Cite this article: Bone Jt Open 2024;5(8):652–661

Purpose and background. Cauda Equina Syndrome (CES), a rare (<1 per 100,000) and potentially devasting condition, involves compression of the lumbosacral nerve roots. If not quickly identified and treated, it can lead to lasting disability, and high medicolegal costs (>£186 million in the decade to 2018). This study identified why people with suspected CES attend the emergency department (ED) and explored any delays in attending. Methods and Results. The design was a secondary analysis of a qualitative dataset comprising patients with back pain who attended the ED, undertaken using an interpretivist approach. Fourteen patients (8M:6F, aged 23–63 years) with suspected CES were purposively sampled from 4 EDs (2 Northern and 2 Southern) in England between August and December 2021. Semi-structured interviews were conducted online, audio-recorded, transcribed verbatim and analysed thematically. Acopia with pain was the biggest factor in a participant's decision to attend the ED, along with the need for a diagnosis. This pain was the worst ever experienced and debilitating, leaving people unable to cope and desperate for relief. 12/14 were advised to attend the ED following identification of red flags by: GPs (n=9); physiotherapists (n=2); surgical colleague (n=1); and 111 (n=1). Factors such as guilt, previous experience of being disregarded, and symptom misattribution were seen to cause delays in seeking care. Conclusion. This paper revealed a disconnect between the priorities of patients and clinicians prior to attending the ED. Clinicians need to validate the pain experience, communicate clearly why signs and symptoms are concerning, and convey the urgency and potential impact of CES. Conflicts of interest. None. Sources of funding. Funding for primary data: Health Education England & National. Institute of Health and Care Research (ICA-CDRF-2018-04-ST2-040)

Background. Mobile apps have shown promise in helping people to self-manage conditions like chronic low back pain (CLBP). However, it is unclear who benefits most, why, and under what circumstances. This limits our understanding of how to maximize the potential of mobile app technology. Aim. This study aimed to test and refine programme theories about how mobile apps support people to self-manage CLBP in a real-world setting. The theories were based on a previously published realist review. Methods. A realist evaluation was conducted using one-to-one realist interviews by telephone with participants who had used the Curable app to self-manage their CLBP for three months. The interviews were guided by programme theories from the realist review. Analysis of the interviews used abductive and retroductive logic to create chains of inferences, which were then developed into context-mechanism-outcome configurations (CMOCs). These CMOCs offered causal explanations about who might benefit from a mobile app to self-manage CLBP, why and in what circumstances. Results. Ten interviews were conducted (nine with people with CLBP who trialled the app and one with a founding member of Curable LLC). Twenty CMOCs were created that identified key mechanisms such as agency, control and reassurance that interact with contextual factors such as acceptance, internal capacity, and a biopsychosocial approach to pain management. These factors influence whether a person with CLBP will benefit from a mobile app for self-management. Conclusions. Twenty CMOCs were created to support three programme theories centering around concepts of empowerment, burden of care, and timing. Conflicts of interest. None. Sources of funding. R Hunter's work was supported by the Inverness and Highland City-Region Deal Studentship Award [2018]. Presented at: 13th Congress of the European Pain Federation (EFIC), September 2023, Budapest, Hungary

Background. The association between lumbar intervertebral disc degeneration (LDD) and low back pain (LBP) is modest. We have recently shown that genetic propensity to pain is an effect modifier of the LDD-LBP relationship when LDD is defined as a summary score of LDD (LSUM), suggesting the association may be driven by individuals with the greatest genetic predisposition to pain. This study examined the association between individual spine magnetic resonance imaging (MRI)-determined LDD features and LBP in subgroups defined by genetic predisposition to pain. Method. We developed a polygenic risk score (PRS) for “genetic propensity to pain” defined as the number of non-back pain locations (head, face, neck/shoulder, stomach/abdomen, hip, and knee) with duration ≥3 months in 377,538 UK Biobank participants of European ancestry. This PRS was used to stratify TwinsUK MRI samples (n=645) into four strata of genetic propensity to pain. We examined the association between LBP and MRI features of lumbar disc height, disc signal intensity, disc bulge, and osteophytes with adjustments for age, sex, PRS strata, interaction terms for each MRI feature x PRS strata, and twin status. Results. We found significant effect modification of the LDD-LBP relationship by genetic propensity to pain for the lumbar MRI features of disc height (p=0.03 for the interaction term with highest quartile of genetically-predicted propensity to pain) and disc signal intensity (p=0.001), but not for disc bulge and osteophytes. Conclusion. Genetic propensity to pain modifies the association between individual LDD features and LBP and should be considered in LBP clinical studies. Conflicts of interest. No conflicts of interest. Sources of funding. No funding obtained. Acknowledgement. UKBB data were obtained under the project #18219. This paper is submitted to the Spine journal and is under review

Purpose and Background. Clinical practice guidelines (CPGs) recommend self-management for low back pain (LBP). Our recent narrative review on self-management needs revealed a consensus with respect to the critical components of self-management interventions. With mobile health advancements, apps offer innovative support for LBP management. This study aims to identify current apps for the self-management of LBP, assessing them for their quality, intervention content, theoretical approaches, and risk management approaches. Methods and Results. We identified 69 apps for LBP self-management from a systematic search in the UK iTunes and Google Play stores. The most recommended interventions are muscle stretching (n=51, 73.9%), muscle strengthening (n=42, 60.9%), and core stability exercises (n=32, 46.4%). The average MARS (SD) overall score for the included apps was 2.4 (0.44) out of a possible 5 points, with the engagement and information dimension scoring the lowest at 2.1. In terms of theoretical and risk management approaches, no apps offered a theoretical care model and all failed to specify the age group targeted; only one (1.4%) provided a tailored care approach; 18 (26.1%) included intervention progression; and 11 (15.9%) reported management safety checks. Conclusion. This study shows that app developers generally select interventions endorsed by CPGs. However, the application of a biopsychosocial care model is not being considered. Most of them are of low quality, lacking theoretical approaches to care and consideration of associated risks. It is essential to involve clinicians and patients in developing LBP self-management apps to improve the quality and related approach. Conflicts of interest. None. Sources of funding. No funding obtained. This study has been published in JMIR mHealth and uHealth

Background and study purpose. A recent systematic review with meta-analysis of eight randomised controlled trials concluded that Cognitive Functional Therapy (CFT) for low back pain might be effective in reducing disability, pain and fear-avoidance beliefs. However, the descriptions of a CFT intervention are not always clear. This study aimed to rate the replicability of the CFT interventions and control groups in the systematic review. Methods. Two reviewers independently extracted data from the study articles, protocols and appendices into Microsoft Excel using the Template for Intervention Description and Replication (TIDieR) checklist. This checklist has 12 items to describe the ‘why’, ‘what’, ‘who’, ‘how’, ‘where’, ‘when and how much’, ‘tailoring’, ‘modifications’, and ‘how well’ for each intervention. We rated the replicability of the CFT interventions and control groups as ‘reported’, ‘partially reported’ and ‘not reported’ and resolved discrepancies by consensus. Results. No studies reported 100% of the TIDieR items; the mean ‘reported’ rating was 54% (range 33–67%) for the CFT interventions and 35% (range 8–67%) for controls. The six most replicable items were the same for both CFT and control groups. These were ‘brief name’ (CFT=100%; control=100%), ‘why’ (CFT=100%; control=50%), ‘how’ (CFT=100%; control=50%), ‘what procedures’ (CFT=88%; control=63%), ‘where’ (CFT=88%; control=75%) and ‘planned adherence’ (CFT=75%; control=38%). Items that were not sufficiently ‘reported’ for either CFT or control groups included ‘when and how much’, ‘tailoring’ and ‘adherence’. Conclusion. Incomplete descriptions of CFT interventions mean that clinicians and patients cannot implement those that have demonstrated effectiveness, and poor descriptions of control groups prevent researchers from replicating them in future studies. Conflict of interest. No conflicts of interest. Sources of funding. No funding obtained

Background and Purpose. The UK's NIHR and Australia's NHMRC have funded two randomised controlled trials (RCTs) to determine if lumbar fusion surgery (LFS) is more effective than best conservative care (BCC) for adults with persistent, severe low back pain (LBP) attributable to lumbar spine degeneration. We aimed to describe clinicians’ decision-making regarding suitability of patient cases for LFS or BCC and level of equipoise to randomise participants in the RCTs. Methods. Two online cross-sectional surveys distributed via UK and Australian professional networks to clinicians involved in LBP care, collected data on clinical discipline, practice setting and preferred care of five patient cases (ranging in age, pain duration, BMI, imaging findings, neurological signs/symptoms). Clinicians were also asked about willingness to randomise each patient case. Results. Of 174 responses (73 UK, 101 Australia), 70 were orthopaedic surgeons, 34 neurosurgeons, 65 allied health professionals (AHPs), 5 others. Most worked in public health services only (92% UK, 45% Australia), or a mix of public/private (36% Australia). Most respondents chose BCC as their first-choice management option for all five cases (81–93% UK, 83–91% Australia). For LFS, UK surgeons preferred TLIF (36.4%), whereas Australian surgeons preferred ALIF (54%). Willingness to randomise cases ranged from 37–60% (UK mean 50.7%), and 47–55% (Australian mean 51.9%); orthopaedic and neuro-surgeons were more willing than AHPs. Conclusion. Whilst BCC was preferred for all five patient cases, just over half of survey respondents in both the UK and Australia were willing to randomise cases to either LFS or BCC, indicating clinical equipoise (collective uncertainty) needed for RCT recruitment. Conflicts of interest. None. Sources of funding. No specific funding obtained for the surveys. DB, SA, AG and NEF have funding from the National Institute for Health Research (NIHR) UK (FORENSIC-UK NIHR134859); NEF, DB and SA have funding from the Australian National Health and Medical Research Council (NHMRC FORENSIC-Australia GA268233). AG has funding from Orthopaedic Research UK (combined with British Association of Spine Surgeons and British Scoliosis Society) and Innovate UK. NEF is funded through an Australian National Health and Medical Research Council (NHMRC) Investigator Grant (ID: 2018182)

Background. Immersive virtual reality (VR) demonstrates potential benefits in patients with chronic low back pain (CLBP). However, few studies have investigated the feasibility and the acceptability of introducing immersive VR for use with patients with CLBP and in the Kingdom of Saudi Arabia (KSA). Aim. To investigate immersive VR's feasibility, tolerability, and acceptability as a rehabilitation intervention for adult patients with CLBP and explore the views of relevant Health Care Practitioners (HCPs) in the KSA. Methodology and Methods. A multi-centre, mixed-methods, explanatory sequential design was adopted to test immersive VR's feasibility, tolerability, and acceptability. An uncontrolled feasibility trial was conducted. The immersive VR intervention involved a training session followed by three sessions over one week using commercially available hardware and software. Feasibility outcomes were collected from patients immediately post-intervention. Patients and HCPs were recruited for semi-structured interviews. Results. Thirty-three patients and three HCPs were recruited. The feasibility a priori criteria were met for recruitment, retention, dropout, completeness of questionnaire data, treatment compliance and fidelity. Adverse events included one who reported aggravation of tinnitus, whereas two experienced dizziness. Qualitative data suggested that entertainment and motivation were key enablers. Barriers included technological capability and HCPs’ perceptions that immersive VR was time-consuming. Conclusion. The results suggested that immersive VR was feasible, acceptable, and tolerable among patients with CLBP and HCPs in clinical settings in the KSA. Further research focusing on the effectiveness is warranted in this field. Conflicts of Interest. None. Sources of Funding. None. Trial registration number. ISRCTN14434517

Background. Lateral lumbar spine statistical shape models (SSM) have been used previously to describe associations with osteoarthritis and back pain. However, associations with factors such as osteoporosis, menopause and parity have not been explored. Methods and Results. A 143-point SSM, describing L1 to the top of L5, was applied to lateral spine iDXA scans from UK Biobank. Associations with self-reported osteoporosis, menopause, parity and back pain and the first 10 modes of variation were examined using adjusted binary logistic regression or linear regression (adjusted for age, height, weight and total spine BMD). We report odds ratios with 95% confidence intervals for each standard deviation change in mode. Complete data were available for 2494 women. Mean age was 61.5 (± 7.4) years. 1369 women reported going through menopause, 96 women self-reported osteoporosis and 339 women reported chronic back pain. 80% of women reported at least 1 live birth. Lumbar spine shape was not associated with back pain in this cohort. Two modes were associated with menopause (modes 1 & 2), 1 mode with parity (mode 1) and 2 modes with osteoporosis (modes 3 & 5). Mode 1 (43.6% total variation), describing lumbar curvature was positively associated with both menopause [OR 1.15 95% CI 1.00–1.33, p=0.05] and parity [OR 1.058 95% CI 1.03–1.0, p=0.01]. Mode 3, describing decreased vertebral height was positively associated with osteoporosis [OR 1.40 95% CI 1.14–1.73, p=0.001]. Conclusion. Menopause and parity were associated with a curvier lumbar spine and osteoporosis with decreased vertebral height. Shape was not associated with back pain. No conflicts of interest.  . Sources of funding. Wellcome Trust collaborative award ref 209233

Purpose and background. Low back pain (LBP), a leading cause of chronic disability, is associated with high and disproportionate socioeconomic costs. Clinical assessment and triage via the NHS 111 service aims to reduce pressure on the urgent and emergency care system. Studies show that many attend the emergency department (ED) against advice, when they could be better managed elsewhere. The aim of this research was to explore how patients with LBP perceive and interact with NHS 111, and how this may have influenced their decision to attend ED. Methods and Results. This was a secondary analysis of a cross-sectional, qualitative dataset of 47 patients (26M:21F, aged 23–79 years) purposively sampled with LBP, who attended 1 of 4 EDs in the UK in 2021, (during the pandemic). The participants took part in online, semi-structured interviews, mean duration 45-minutes (range 23–156 minutes), within six weeks of their ED visit. The interviews were audio-recorded, transcribed verbatim and thematically analysed. Three key themes were identified: purpose, process and performance. The themes showed mixed understanding and low awareness of the purpose of NHS 111, despite its strong triage role. Long waits for call backs however, sometimes resulted in patients attending ED, along with previous negative perspectives and experiences. Conclusion. This research suggests enhanced visibility and knowledge of NHS 111 would increase its use by people with LBP. Further exploration comparing outcomes of callers to NHS 111 with those who seek care elsewhere, could help evaluate how NHS 111 can best help people with LBP and prevent unnecessary ED attendance. No conflicts of interest.  . Sources of funding. Funding for primary data: Health Education England & National Institute of Health and Care Research (ICA-CDRF-2018-04-ST2-040)

Purpose/Background. Health inequalities are defined as unfair and avoidable differences in health across the population. People belonging to inclusion health groups are most at risk of experiencing these inequalities and tackling them is an NHS priority. Inclusion health groups include ‘people in contact with the justice system’ and BCHC NHS FT is commissioned to provide physiotherapy to prisoners at HMP Birmingham. The purpose of this study was to better understand the MSK health-status and MSK conditions affecting this minoritised patient population. Methods/Results. The MSK service at HMP Birmingham collects the MSK-HQ PROM for all prisoners attending physiotherapy. A retrospective analysis of the electronic patient record was performed using convenience sampling, with baseline MSK-HQ scores of prisoners seen between 01/04/2023 and 01/02/2024 captured alongside the primary presenting MSK condition. Simple descriptive statistics were used to evaluate the data. A total of 129 patients attended initial physiotherapy appointments within the time-period. Baseline MSK-HQ was collected for 62 patients (48%) with a mean (SD) score of 23.08(11.38). The most common MSK condition was Back pain with a count of 12(19.35%). The mean (SD) MSK-HQ score for prisoners with back pain was 22.08(9.98). Conclusion. This is the first known evaluation in the published literature of the baseline MSK health-status and primary MSK conditions affecting prisoners. A published evaluation of baseline MSK health-status for patients attending a community MSK service reported a mean (SD) MSK-HQ of 28.59(10.80) indicating that, a poorer MSK health-status is experienced by this minoritised group. Further work, co-produced with prisoners, is planned to explore further. Conflicts of interest. None. Sources of funding. None

Purpose and background of the study. Self-management and behaviour change is at the core of back pain management. Despite the high-rate of recurrence and healthcare utilisation, clinical guidelines do not include guidance for clinicians on return consultations. This project aimed to identify primary care clinicians’ reported practices and experiences of delivering self-management advice for people returning with persistent low back pain (LBP), to inform future delivery of self-management care. Methods and Results. In this qualitative study involving 27 primary care clinicians, four focus groups and two semi-structure interviews were conducted online. GPs (n=5) and physiotherapists working in primary care roles (First contact practitioners n=7, community and interface roles n=7, and mixed roles n=8) in England and Scotland shared their experience of delivering self-management advice to people returning with persistent LBP. Video recordings were transcribed verbatim and analysed with reflexive thematic analysis. Clinicians unanimously shared their frustrations identifying the challenges involved in supporting people who return with LBP. Helpful strategies to support self-management in return consultations were identified by clinicians in addition to service and system-level changes vital to optimise care. Patient-factors affecting delivery of care, lack of defined responsibility and challenges in meeting patients’ expectations illustrated the tensions that exist in return consultations. Conclusion. This novel study provides insight into the experiences and practices of the frontline primary care workforce seeing patients return with persistent or recurrent LBP. It identifies the tensions that exist between services, professional roles and between clinicians and patients regarding self-management. Important practice implications have been identified to improve information-sharing, agenda-setting, and exploring expectations. No conflicts of interest.  . Source of funding. Lisa Osborn-Jenkins is funded by University Hospital Southampton NHS Foundation Trust (UHS) Research & Development PhD Fellowship [GRT0723]

Background. Disability is an important multifaceted construct. Identifying sources of disability could help optimise patient care. The aim of this study was to test an approach that not only estimates severity of disability, but also identifies the source(s) of this disability. Methods. An online survey was used to collect data from a convenience sample, recruited via email and social media invitations. Two generic measures of disability, the 8-item Universal Disability Index (UDI8) and Groningen Activity Restriction Scale (GARS) were used to estimate the prevalence and severity of disability in this sample. Non-zero UDI8 item responses generated conditional sub-questions, in which participants could attribute their activity limitations to one or more sources (pain, fatigue, worry, mood, and other). This allowed for a decomposition of UDI8 scores into source components. Results. 403 participants enrolled; 334 completed all UDI8 and GARS items. Of these, 85.3% (285/334) reported at least one restricted activity via the UDI8, while 43.4% (145/334) reported some reduced independence via the GARS. Disability severity increased with age until approximately 40 years, after which it decreased gradually. Pain component scores were high in all individuals with higher and lower disability severity, whereas fatigue component scores were highest in individuals reporting higher disability severity. Worry, mood, and other component scores were not high at any level of disability severity. Conclusions. This approach should be used to identify the prevalence, severity and sources of disability in the general population and in specific patient groups. Conflicts of interest. No conflicts of interest. Sources of funding. No funding obtained

Objectives. Understanding lumbar facet joint involvement and biomechanical changes post spinal fusion is limited. This study aimed to establish an in vitro model assessing mechanical effects of fusion on human lumbar facet joints, employing synchronized motion, pressure, and stiffness analysis. Methods and Results. Seven human lumbar spinal units (age 54 to 92, ethics 15/YH/0096) underwent fusion via a partial nucleotomy model mimicking a lateral cage approach with PMMA cement injection. Mechanical testing pre and post-fusion included measuring compressive displacement and load, local motion capture, and pressure mapping at the facet joints. pQCT imaging (82 microns isotropic) was carried out at each stage to assess the integrity of the vertebral endplates and quantify the amount of cement injected. Before fusion, relative facet joint displacement (6.5 ± 4.1 mm) at maximum load (1.1 kN) exceeded crosshead displacement (3.9 ± 1.5 mm), with loads transferred across both facet joints. After fusion, facet displacement (2.0 ± 1.2 mm) reduced compared to pre-fusion, as was the crosshead displacement (2.2 ± 0.6 mm). Post-fusion loads (71.4 ± 73.2 N) transferred were reduced compared to pre-fusion levels (194.5 ± 125.4 N). Analysis of CT images showed no endplate damage post-fusion, whilst the IVD tissue: cement volume ratio did not correlate with the post-fusion behaviour of the specimens. Conclusion. An in vitro model showed significant facet movement reduction with stand-alone interbody cage placement. This technique identifies changes in facet movement post-fusion, potentially contributing to subsequent spinal degeneration, highlighting its utility in biomechanical assessment. Conflicts of interest. None. Sources of funding. This work was funded by EPSRC, under grant EP/W015617/1

Background. Trunk muscles play an important role in supporting the spinal column. A decline in trunk muscle mass, as measured by bioelectrical impedance analysis (TMM–BIA), is associated with low back pain and poor quality of life. Purpose. The purpose of this study was to determine whether TMM–BIA correlates with quantitative and functional assessments traditionally used for the trunk muscles. Methods. We included 380 participants (aged ≥ 65 years; 152 males, 228 females) from the Shiraniwa Elderly Cohort (Shiraniwa) study, for whom the following data were available: TMM–BIA, lumbar magnetic resonance imaging (MRI), and back muscle strength (BMS). We measured the cross-sectional area (CSA) and fat-free CSA of the paravertebral muscles (PVM), including the erector spinae (ES), multifidus (MF), and psoas major (PM), on an axial lumbar MRI at L3/4. The correlation between TMM–BIA and the CSA of PVM, fat-free CSA of PVM, and BMS was investigated. Results. TMMBIA correlated with the CSA of total PVM and each individual PVM. A stronger correlation between TMM–BIA and fat-free CSA of PVM was observed. The TMM–BIA also strongly correlated with BMS. Conclusion. TMM–BIA is an easy and reliable way to evaluate the trunk muscle mass in a clinical setting. Conflict of interest. None. Sources of funding. None

Background. Disability is an important multifaceted construct. The aim of this study was to develop and evaluate a brief, generic self-reported disability questionnaire: the Universal Disability Index (UDI). Methods. Convenience sampling was used to collect general population data via an online survey. Data were randomly divided into training and validation subsets. The dimensionality and structure of eight UDI questionnaire items were evaluated using exploratory factor analysis (EFA, training subset) followed by confirmatory factor analysis (CFA, validation subset). To assess concurrent validity, the UDI summed score from the full dataset was compared to the Groningen Activity Restriction Scale (GARS) and the Graded Chronic Pain Scale (GCPS) disability scores. Internal consistency was also assessed. Results. 403 participants enrolled; 364 completed at least one UDI item. Three single-factor versions of the UDI were assessed (8-item, 7-item, and 6-item). All versions performed well during EFA and CFA (182 cases assigned to each), but none met the RMSEA (Root Mean Square Error of Approximation) criterion (≤ 0.08). All versions of the UDI had high internal consistency (Cronbach's α > 0.90) and were strongly correlated (Pearson's r > 0.7) with both GARS and GCPS disability scores, indicating concurrent validity. Conclusions. A brief, generic self-reported disability questionnaire was found to be valid and to possess good psychometric properties. The UDI has a single factor structure and either a 6-item, 7-item or 8-item version can be used to measure disability. For brevity and parsimony, the 6-item UDI is recommended, but further testing of all versions is warranted. Conflicts of interest. No conflicts of interest. Sources of funding. No funding obtained

Background. Over 55,000 spinal operations are performed annually in the NHS. Effective postoperative analgesia facilitates early mobilisation and assists rehabilitation and hospital discharge, but is difficult to achieve with conventional, opioid-based, oral analgesia. The clinical and cost-effectiveness of two alternative techniques, namely intrathecal opioid and the more novel erector-spinae plane blockade, is unknown. The Pain Relief After Instrumented Spinal Surgery (PRAISE) trial aims to evaluate these techniques. Methods. PRAISE is a multicentre, prospective, parallel group, patient-blinded, randomised trial, seeking to recruit 456 adult participants undergoing elective, posterior lumbar-instrumented spinal surgery from up to 25 NHS hospitals. Participants will be randomised 1:1:1 to receive (1) Usual Care with local wound infiltration, (2) Intrathecal Opioid plus Usual Care with local wound infiltration or (3) Erector Spinae Plane blockade plus Usual Care with no local wound infiltration. The primary outcome is pain on movement on a 100mm visual analogue scale at 24 hours post-surgery. Secondary outcomes include pain at rest, leg pain, quality of recovery (QoR-15), postoperative opioid consumption, time to mobilisation, length of hospital stay, health utility (EQ-5D-5L), adverse events and resource use. Parallel economic evaluation will estimate incremental cost-effectiveness ratios. Results. Differences in the primary outcome at 24 hours will be estimated by mixed-effects linear regression modelling, with fixed effects for randomisation factors and other important prognostic variables, and random effects for centre, using the as-randomised population. Treatment effects with 95% confidence intervals will be presented. Conclusion. The study is due to open in May 2024 and complete in 2026. Conflicts of Interest. No conflicts of interest declared. Sources of Funding. NIHR Health Technology Award – grant number NIHR153170. Trial presentations so far. APOMP 2023 and 2024; RCOA conference, York, November 2023; Faculty of Pain Management training day, London, February 2024