Item response theory validation of the Oxford knee score and Activity and Participation Questionnaire: a step toward a common metric.

OBJECTIVES: The Oxford knee score (OKS) and OKS Activity and Participation Questionnaire (OKS-APQ) are patient-reported outcome measures used to assess people undergoing knee replacement surgery. They have not explicitly been tested for unidimensionality (whether they measure one underlying trait such as 'knee health'). This study applied item response theory (IRT) to improve the validity of the instruments to optimize for ongoing use. STUDY DESIGN AND SETTING: Participants undergoing primary total knee replacement (TKR) provided preoperative and postoperative responses for OKS and OKS-APQ. Confirmatory factor analysis (CFA) were performed on the OKS and OKS-APQ separately and then on both when pooled into one. An IRT model was fitted to the data. RESULTS: 2972 individual response patterns were analyzed. CFA demonstrated that when combining OKS and OKS-APQ as one instrument, they measure one latent health trait. A user-friendly, free-to-use, web app has been developed to allow clinicians to upload raw data and instantly receive IRT scores. CONCLUSIONS: The OKS and OKS-APQ can be combined to use effectively as a single instrument (producing a single score). For the separate OKS and OKS-APQ the original items and response options can continue to be posed to patients, and this study has confirmed the suitability of IRT-weighted scoring. Applying IRT to existing responses converts traditional sum scores into continuous measurements with greater granularity, including individual measurement error.

What recovery domains are important following a total knee replacement? A qualitative, interview-based study.

OBJECTIVES: To explore people's views of recovery from total knee replacement (TKR) and which recovery domains they felt were important. DESIGN: Semi-structured interviews exploring the views of individuals about to undergo or who have undergone TKR. A constant-comparative approach with thematic analysis was used to identify themes. The process of sampling, collecting data and analysis were continuous and iterative throughout the study, with interviews ceasing once thematic saturation was achieved. SETTING: Tertiary care centre. PARTICIPANTS: A purposive sample was used to account for variables including pre, early or late postoperative status. RESULTS: 12 participants were interviewed, 4 who were preoperative, 4 early postoperative and 4 late postoperative. Themes of pain, function, fear of complications, awareness of the artificial knee joint and return to work were identified. Subthemes of balancing acute and chronic pain were identified. CONCLUSIONS: The results of this interview-based study identify pain and function, in particular mobility, that were universally important to those undergoing TKR. Surgeons should consider exploring these domains when taking informed consent to enhance shared decision-making. Researchers should consider these recovery domains when designing interventional studies.

Diagnostic impacts on management of soft tissue injuries associated with tibial plateau fractures: A narrative review.

INTRODUCTION: Currently there is no consensus on the need for investigating knee ligamentous and meniscal injuries in a patient with a tibial plateau fracture. Consequently, many soft tissue injuries are likely undiagnosed and therefore untreated. The impact this has on long term knee outcomes is not well defined. We aimed to identify the impacts of various diagnostic methods on the management of meniscal injuries associated with tibial plateau fractures and evaluate the clinical outcomes. MATERIALS AND METHODS: We performed a systematic review using Pubmed, Medline, Embase, CINAHL and Cochrane following Cochrane guidelines. We included studies that operatively managed tibial plateau fractures and soft tissue injuries, which were diagnosed with either preoperative MRI, intra-operative arthroscopy or arthrotomy. RESULTS: 18 articles with 884 people, with a mean age of 46.4 years were included. Soft tissue injuries were detected on MRI (32-73%) and arthroscopy (12-70%), of which the most common were lateral meniscal injuries (7-64% of tibial plateau fractures). When identified by arthroscopy and arthrotomy, these injuries were almost always treated, either by repair or debridement. The clinical outcomes of these patients were poorly reported, with a heterogenous use of patient reported outcome measures, and follow up time points. There were no randomised trials or control groups for comparative analysis, however operative treatment yielded good to excellent outcomes. CONCLUSION: There is a high incidence of concomitant soft tissue injuries with tibial plateau fractures, particularly lateral meniscal injuries. There are 2 main approaches to meniscal injuries: surgeons who don't investigate, don't treat, whilst surgeons who do investigate often do surgically treat. Although studies that treated these injuries achieved good to excellent results, the currently available evidence doesn't confirm treatment superiority. As there is plausibility for better outcomes, randomised studies are needed to further investigate this clinical question.

Item Response Theory Validation of the Forgotten Joint Score for Persons Undergoing Total Knee Replacement.

BACKGROUND: The Forgotten Joint Score (FJS), a commonly used patient-reported outcome measure, was developed without fully confirming assumptions such as unidimensionality (all items reflect 1 underlying factor), appropriate weighting of each item in scoring, absence of differential item functioning (in which different groups, e.g., men and women, respond differently), local dependence (pairs of items are measuring only 1 underlying factor), and monotonicity (persons with higher function have a higher score). We applied item response theory (IRT) to perform validation of the FJS according to contemporary standards, and thus support its ongoing use. We aimed to confirm that the FJS reflects a single latent trait. In addition, we aimed to determine whether an IRT model could be fitted to the FJS. METHODS: Participants undergoing primary total knee replacement provided responses to the FJS items preoperatively and at 6 and 12 months postoperatively. An exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and Mokken analysis were conducted. A graded response model (GRM) was fitted to the data. RESULTS: A total of 1,774 patient responses were analyzed. EFA indicated a 1-factor model (all 12 items reflecting 1 underlying trait). CFA demonstrated an excellent model fit. Items did not have equal weighting. The FJS demonstrated good monotonicity and no differential item functioning by sex, age, or body mass index. GRM parameters are reported in this paper. CONCLUSIONS: The FJS meets key validity assumptions, supporting its use in clinical practice and research. The IRT-adapted FJS has potential advantages over the traditional FJS: it provides continuous measurements with finer granularity between health states, includes individual measurement error, and can compute scores despite more missing data (with only 1 response required to estimate a score). It can be applied retrospectively to existing data sets or used to deliver individualized computerized adaptive tests. LEVEL OF EVIDENCE: Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Robotic trials in arthroplasty surgery.

Total hip and knee arthroplasty (THA, TKA) are largely successful procedures; however, both have variable outcomes, resulting in some patients being dissatisfied with the outcome. Surgeons are turning to technologies such as robotic-assisted surgery in an attempt to improve outcomes. Robust studies are needed to find out if these innovations are really benefitting patients. The Robotic Arthroplasty Clinical and Cost Effectiveness Randomised Controlled Trials (RACER) trials are multicentre, patient-blinded randomized controlled trials. The patients have primary osteoarthritis of the hip or knee. The operation is Mako-assisted THA or TKA and the control groups have operations using conventional instruments. The primary clinical outcome is the Forgotten Joint Score at 12 months, and there is a built-in analysis of cost-effectiveness. Secondary outcomes include early pain, the alignment of the components, and medium- to long-term outcomes. This annotation outlines the need to assess these technologies and discusses the design and challenges when conducting such trials, including surgical workflows, isolating the effect of the operation, blinding, and assessing the learning curve. Finally, the future of robotic surgery is discussed, including the need to contemporaneously introduce and evaluate such technologies.

What's important for recovery after a total knee replacement? A systematic review of mixed methods studies.

BACKGROUND: Understanding how patients perceive and prioritise various aspects of recovery following total knee replacement, including pain, function and return to activity, will help clinicians in pre-operative consultations by ensuring they effectively address patient concerns and managing their expectations. AIMS: The aim of this study is to identify aspects of recovery that are important to people after a total knee replacement. METHODS: Studies were identified from Medline, Embase, PsycInfo, Cochrane Library and Web of Science. This mixed methods review included all original study types (quantitative, qualitative, discrete choice experiments and mixed methods design). Reviews and non-peer-reviewed publications were excluded. Studies with participants (age ≥ 18 years) who had a primary TKR for osteoarthritis were included. Studies of people with unicompartmental knee, patella-femoral or revision knee replacement were excluded. Recovery attributes were extracted from individual papers and grouped into recovery themes. RESULTS: A total of 23 studies with 8404 participants and 18 recovery themes were developed. The most frequently identified overarching theme was pain, followed by activities of daily living, mobility (walking), recreational activities, specific functional movements of the knee, use of walking aids, sexual activity and range of motion of the knee. Medical complications were an infrequently reported theme, however, was deemed to be high importance. CONCLUSIONS: Reducing pain, returning of activities and daily living and mobility are the three most frequently reported recovery domains for people after TKR. Clinicians should be aware of recovery themes, to ensure they are explored sufficiently when consenting for a TKR. Future research should aim to determine the relative importance of these attributes compared to each other. Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021253699.

UK robotic arthroplasty clinical and cost effectiveness randomised controlled trial for hips (RACER-Hip): a study protocol.

INTRODUCTION: The number of robotic-assisted hip replacement procedures has expanded globally with the intended aim of improving outcomes. Intraoperative robotic-arm systems add additional costs to total hip replacement (THR) surgery but may improve surgical precision and could contribute to diminished pain and improved function. Additionally, these systems may reduce the need for expensive revision surgery. Surgery with conventional instruments may be just as successful, quick and affordable. There is timely demand for a robust evaluation of this technology. METHODS AND ANALYSIS: The Robotic Arthroplasty Clinical and cost Effectiveness Randomised controlled trial for Hips (RACER-Hip) is a multicentre (minimum of six UK sites), participant-assessor blinded, randomised controlled trial. 378 participants with hip osteoarthritis requiring THR will be randomised (1:1) to receive robotic-assisted THR, or THR using conventional surgical instruments. The primary outcome is the Forgotten Joint Score at 12 months post-randomisation; a patient-reported outcome measure assessing participants' awareness of their joint when undertaking daily activities. Secondary outcomes will be collected post-operatively (pain, blood loss and opioid usage) and at 3, 6, 12, 24 months, then 5 and 10 years postrandomisation (including function, pain, health-related quality of life, reoperations and satisfaction). Allocation concealment will be accomplished using a computer-based randomisation procedure on the day of surgery. Blinding methods include the use of sham incisions for marker clusters and blinded operation notes. The primary analysis will adhere to the intention-to-treat principle. Results will adhere to Consolidated Standards of Reporting Trials statements. ETHICS AND DISSEMINATION: The trial was approved by an ethics committee (Solihull Research Ethics Committee, 30 June 2021, IRAS: 295831). Participants will provide informed consent before agreeing to participate. Results will be disseminated using peer-reviewed journal publications, presentations at international conferences and through the use of social media. We will develop plans to disseminate to patients and public with our patient partners. TRIAL REGISTRATION NUMBER: ISRCTN13374625.

Robotic Arthroplasty Clinical and cost Effectiveness Randomised controlled trial (RACER-knee): a study protocol.

INTRODUCTION: Robotic-assisted knee replacement systems have been introduced to healthcare services worldwide in an effort to improve clinical outcomes for people, although high-quality evidence that they are clinically, or cost-effective remains sparse. Robotic-arm systems may improve surgical accuracy and could contribute to reduced pain, improved function and lower overall cost of total knee replacement (TKR) surgery. However, TKR with conventional instruments may be just as effective and may be quicker and cheaper. There is a need for a robust evaluation of this technology, including cost-effectiveness analyses using both within-trial and modelling approaches. This trial will compare robotic-assisted against conventional TKR to provide high-quality evidence on whether robotic-assisted knee replacement is beneficial to patients and cost-effective for healthcare systems. METHODS AND ANALYSIS: The Robotic Arthroplasty Clinical and cost Effectiveness Randomised controlled trial-Knee is a multicentre, participant-assessor blinded, randomised controlled trial to evaluate the clinical and cost-effectiveness of robotic-assisted TKR compared with TKR using conventional instruments. A total of 332 participants will be randomised (1:1) to provide 90% power for a 12-point difference in the primary outcome measure; the Forgotten Joint Score at 12 months postrandomisation. Allocation concealment will be achieved using computer-based randomisation performed on the day of surgery and methods for blinding will include sham incisions for marker clusters and blinded operation notes. The primary analysis will adhere to the intention-to-treat principle. Results will be reported in line with the Consolidated Standards of Reporting Trials statement. A parallel study will collect data on the learning effects associated with robotic-arm systems. ETHICS AND DISSEMINATION: The trial has been approved by an ethics committee for patient participation (East Midlands-Nottingham 2 Research Ethics Committee, 29 July 2020. NRES number: 20/EM/0159). All results from the study will be disseminated using peer-reviewed publications, presentations at international conferences, lay summaries and social media as appropriate. TRIAL REGISTRATION NUMBER: ISRCTN27624068.

The meniscal tear outcome (METRO) review: A systematic review summarising the clinical course and outcomes of patients with a meniscal tear.

BACKGROUND: Meniscal tears affect 222 per 100,000 of the population and can be managed non-operatively or operatively with an arthroscopic partial meniscectomy (APM), meniscal repair or meniscal transplantation. The purpose of this review is to summarise the outcomes following treatment with a meniscal tear and explore correlations between outcomes. METHOD: A systematic review was performed of MEDLINE, EMBASE, AMED and the Cochrane Central Register of Controlled Trials to identify prospective studies describing the outcomes of patients with a meniscal tear. Comparisons were made of outcomes between APM and non-operative groups. Outcomes were graphically presented over time for all treatment interventions. Pearson's correlations were calculated between outcome timepoints. RESULTS: 35 studies were included, 28 reported outcomes following APM; four following meniscal repair and three following meniscal transplant. Graphical plots demonstrated a sustained improvement for all treatment interventions. A moderate to very strong correlation was reported between baseline and three-month outcomes. In the medium term, there was small significant difference in outcome between APM and non-operative measures (SMD 0.17; 95 % CI 0.04, 0.29), however, this was not clinically significant. CONCLUSIONS: Patients with a meniscal tear demonstrated a sustained initial improvement in function scores, which was true of all treatments examined. APM may have little benefit in older people, however, previous trials did not include patients who meet the current indications for surgery as a result the findings should not be generalised to all patients with a meniscal tear. Further trials are required in patients who meet current operative indications.

Meniscal tears are more common than previously identified, however, less than a quarter of people with a tear undergo arthroscopy.

PURPOSE: The management of meniscal tears is a widely researched and evolving field. Previous studies reporting the incidence of meniscal tears are outdated and not representative of current practice. The aim of this study was to report the current incidence of MRI confirmed meniscal tears in patients with a symptomatic knee and the current intervention rate in a large NHS trust. METHODS: Radiology reports from 13,358 consecutive magnetic resonance imaging scans between 2015 and 2017, performed at a large UK hospital serving a population of 470,000, were assessed to identify patients with meniscal tears. The hospital database was interrogated to explore the subsequent treatment undertaken by the patient. A linear regression model was used to identify if any factors predicted subsequent arthroscopy. RESULTS: 1737 patients with isolated meniscal tears were identified in patients undergoing an MRI for knee pain, suggesting a rate of 222 MRI confirmed tears per 100,000 of the population aged 18 to 55 years old. 47% attended outpatient appointments and 22% underwent arthroscopy. Root tears [odds ratio (95% CI) 2.24 (1.0, 4.49); p = 0.049] and bucket handle tears were significantly associated with subsequent surgery, with no difference between the other types of tears. The presence of chondral changes did not significantly affect the rate of surgery [0.81 (0.60, 1.08); n.s]. CONCLUSION: Meniscal tears were found to be more common than previously described. However, less than half present to secondary care and only 22% undergo arthroscopy. These findings should inform future study design and recruitment strategies. In agreement with previous literature, bucket handle tears and root tears were significant predictors of subsequent surgery. LEVEL OF EVIDENCE: III.

ARthroscopy in Knee OsteoArthritis (ARK-OA): a multicentre study assessing compliance to national guidelines.

INTRODUCTION: The use of arthroscopy to alleviate the symptoms of osteoarthritis has been questioned by recent high quality evidence. This has led to the development of guidelines by specialist and national bodies advocating against its use. AIMS: To examine the trends of the rates of arthroscopy in patients with knee osteoarthritis over the past five years and determining compliance with guidelines. METHODS: Multi-centre, retrospective audit in five hospital trusts in the United Kingdom. The number of arthroscopies performed by month from 2013 to 2017 was identified through hospital coding. Fifty randomly selected records from the year 2017 were further analysed to assess compliance with NICE guidelines. RESULTS: Between 2013 and 2017, the number of arthroscopies performed annually in five trusts dropped from 2028 to 1099. In the year 2017, 17.7% of patients with no mechanical symptoms and moderate-to-severe arthritis pre-operatively had arthroscopy. CONCLUSION: Knee arthroscopy continues to be used as a treatment for osteoarthritis, against national guidelines. Whilst overall numbers are declining, further interventions, including implementation of high-quality conservative care is required to further eliminate unnecessary procedures.

Meniscal Tear Outcome (METRO) review: a protocol for a systematic review summarising the clinical course and patient experiences of meniscal tears in the current literature.

INTRODUCTION: Meniscal tears are a common knee injury with an incidence of 60 per 100 000. Management of meniscal tears can include either non-operative measures or operative procedures such as arthroscopic partial meniscectomy (APM). Despite substantial research evaluating the effectiveness of APM in the recent past, little is known about the clinical course or the experiences of patients with a meniscal tear. AIM: To summarise the short to long-term patterns of variability in outcome in patients with a meniscal tear.To summarise the evidence on patient experiences of meniscal tears. In particular, we will focus on patient experiences of treatment options, treatment pathways and their views of the outcomes used in meniscal tear research. METHODS AND ANALYSIS: Two search strategies will be developed to identify citations from EMBASE, MEDLINE, AMED, CENTRAL, Web of Science and Sociofile. The date of our planned search is 14 August 2020. For the quantitative review we will identify studies reporting patient-reported outcome measures in patients after a meniscal tear. The standardised mean change will be used to assess the variation in size of response and summarise the overall response to each treatment option. All studies will undergo quality assessment using either the Cochrane risk of bias or the Newcastle-Ottawa tool.A qualitative systematic review will be used to identify studies reporting views and experiences of patients with a meniscal tear. All studies will be assessed using the Critical Appraisal Skills Programme tool and if sufficient data are present a meta-synthesis will be performed to identify first, second and third-order constructs. ETHICS AND DISSEMINATION: Given the nature of this study, no formal ethical approval will be sought. Results from the review will be disseminated at national conferences and will be submitted to a peer-reviewed journal for publication. Lay summaries will be freely available via the study Twitter page. PROSPERO REGISTRATION NUMBER: CRD42019122179.

Use of three-dimensional printing in preoperative planning in orthopaedic trauma surgery: A systematic review and meta-analysis.

BACKGROUND: With the increasing complexity of surgical interventions performed in orthopaedic trauma surgery and the improving technologies used in three-dimensional (3D) printing, there has been an increased interest in the concept. It has been shown that 3D models allow surgeons to better visualise anatomy, aid in planning and performing complex surgery. It is however not clear how best to utilise the technique and whether this results in better outcomes. AIM: To evaluate the effect of 3D printing used in pre-operative planning in orthopaedic trauma surgery on clinical outcomes. METHODS: We performed a comprehensive systematic review of the literature and a meta-analysis. Medline, Ovid and Embase were searched from inception to February 8, 2018. Randomised controlled trials, case-control studies, cohort studies and case series of five patients or more were included across any area of orthopaedic trauma. The primary outcomes were operation time, intra-operative blood loss and fluoroscopy used. RESULTS: Seventeen studies (922 patients) met our inclusion criteria and were reviewed. The use of 3D printing across all specialties in orthopaedic trauma surgery demonstrated an overall reduction in operation time of 19.85% [95% confidence intervals (CI): (-22.99, -16.71)], intra-operative blood loss of 25.73% [95%CI: (-31.07, -20.40)], and number of times fluoroscopy was used by 23.80% [95%CI: (-38.49, -9.10)]. CONCLUSION: Our results suggest that the use of 3D printing in pre-operative planning in orthopaedic trauma reduces operative time, intraoperative blood loss and the number of times fluoroscopy is used.

Determining the stress biomarker profile in patients undergoing total knee replacement and the relationship with outcome at 12 months.

BACKGROUND: Total knee replacement (TKR) is the commonest joint arthroplasty procedure worldwide. Despite excellent outcomes, some studies have reported dissatisfaction in up to 20% of patients. There is evidence of an association between the biochemical stress response to surgery and outcomes. The objective of this study is to describe the stress biomarker profile for TKR, and correlate this with patient outcomes. METHODS: A prospective cohort study of 50 patients undergoing primary TKR was conducted. Serum IL-6, TNF-α, neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) were measured immediately pre- and post-operatively, and on Days 1 and 3. Follow-up questionnaires including the Oxford Knee Score (OKS) and EuroQol five dimensions (EQ-5D) were completed at 12-months. Univariate analysis was completed using a linear regression model (p < 0.05). RESULTS: Serum IL-6, NLR, and PLR all increased to Day 1 post-operatively, and decreased by Day 3. TNF-α values increased across all time points. Statistical analysis found a significant negative correlation (r = -0.414; p = 0.005) between pre-operative IL-6 and 12-month OKS. There was a significant positive correlation between pre-operative NLR and 12 month OKS (r = 0.272; p = 0.039) and 12 month EQ5D (r = 0.268; p = 0.043). CONCLUSION: This is the first study to describe the biochemical stress response to TKR. The results raise the potential for a pre-operative risk stratification tool for patients based on IL-6 and NLR measurements. Further research should be conducted to explore the underlying mechanisms involved, and investigate interventions to reduce pre-operative physiological stress with a view to improving post-operative outcomes.

Tibial component sizing and alignment of TKR components does not significantly affect patient reported outcome measures at six months. A case series of 474 participants.

OBJECTIVES: Total knee replacement (TKR) is an effective means of alleviating the symptoms of end stage osteoarthritis. However, 20% of patients report dissatisfaction one year post-operatively. Previous literature has demonstrated contradictory evidence regarding the relationship between alignment and tibial component sizing with patient reported outcome measures (PROMs). We aim to investigate the association between alignment of TKR components and effect of tibial component sizing on PROMs. METHOD: A prospective, multicentre case series was performed at six centres. Baseline characteristics were collected at recruitment. Coronal and sagittal plain films were taken day one post-operatively. Trained medical professionals blinded to outcome measured the alignment and degree of over/underhang of the tibial component in the coronal and sagittal place, with Oxford Knee Score (OKS) measured six months post-operatively. RESULTS: 474 patients were recruited. Malaligned TKRs caused no significant difference in mean OKS change at six months (independent t-test) (p > 0.05). A multivariate regression model taking into account age, gender, body mass index and baseline OKS also demonstrated no significant difference (p > 0.05). With regards to tibial component sizing, 125 (27%) of patients had appropriately sized tibial components, 120 (26%) had overhang and 219 (53%) had underhang with no significant difference in OKS between the groups (p > 0.05). CONCLUSION: Tibial component sizing and alignment does not significantly affect short-term function, as measured by OKS, after total knee replacement. Dissatisfaction after TKR is likely due to other factors other than alignment of implant.

Determining Surgical Complications in the Overweight (DISCOVER): a multicentre observational cohort study to evaluate the role of obesity as a risk factor for postoperative complications in general surgery.

INTRODUCTION: Obesity is increasingly prevalent among patients undergoing surgery. Conflicting evidence exists regarding the impact of obesity on postoperative complications. This multicentre study aims to determine whether obesity is associated with increased postoperative complications following general surgery. METHODS AND ANALYSIS: This prospective, multicentre cohort study will be performed utilising a collaborative methodology. Consecutive adults undergoing open or laparoscopic, elective or emergency, gastrointestinal, bariatric or hepatobiliary surgery will be included. Day case patients will be excluded. The primary end point will be the overall 30-day major complication rate (Clavien-Dindo grade III-V complications). Data will be collected to risk-adjust outcomes for potential confounding factors, such as preoperative cardiac risk. This study will be disseminated through structured medical student networks using established collaborative methodology. The study will be powered to detect a two-percentage point increase in the major postoperative complication rate in obese versus non-obese patients. ETHICS AND DISSEMINATION: Following appropriate assessment, an exemption from full ethics committee review has been received, and the study will be registered as a clinical audit or service evaluation at each participating hospital. Dissemination will take place through national and local research collaborative networks.

Chronic safety assessment of hemostatic self-expanding foam: 90-day survival study and intramuscular biocompatibility.

BACKGROUND: Noncompressible hemorrhage is a significant cause of preventable death in trauma, with no effective presurgical treatments. We previously described the efficacy and 28-day safety of a self-expanding hemostatic foam in swine models. We hypothesized that the 28-day results would be confirmed at a second site and that results would be consistent over 90 days. Finally, we hypothesized that the foam material would be biocompatible following intramuscular implantation. METHODS: Foam treatment was administered in swine following a closed-cavity splenic injury. The material was explanted after 3 hours, and the animals were monitored to 28 days (n = 6) or 90 days (n = 4). Results were compared with a control group with injury alone (n = 6 at 28 days, n = 3 at 90 days). In a separate study, foam samples were implanted in rabbit paravertebral muscle and assessed at 28 days and 90 days relative to a Food and Drug Administration-approved polyurethane mesh (n = 3 per group). RESULTS: All animals survived the acute phase of the study, and the foam animals required enterorrhaphy. One animal developed postoperative ileus and was euthanized; all other animals survived to the 28-day or 90-day end point without clinically significant complications. Histologic evaluation demonstrated that remnant particles were associated with a fibrotic capsule and mild inflammation. The foam was considered biocompatible in 28-day and 90-day intramuscular implant studies. CONCLUSION: Foam treatment was not associated with significant evidence of end-organ dysfunction or toxicity at 28 days or 90 days. Remnant foam particles were well tolerated. These results support the long-term safety of this intervention for severely bleeding patients.

Promoting research and audit at medical school: evaluating the educational impact of participation in a student-led national collaborative study.

BACKGROUND: Medical students often struggle to engage in extra-curricular research and audit. The Student Audit and Research in Surgery (STARSurg) network is a novel student-led, national research collaborative. Student collaborators contribute data to national, clinical studies while gaining an understanding of audit and research methodology and ethical principles. This study aimed to evaluate the educational impact of participation. METHODS: Participation in the national, clinical project was supported with training interventions, including an academic training day, an online e-learning module, weekly discussion forums and YouTube® educational videos. A non-mandatory, online questionnaire assessed collaborators' self-reported confidence in performing key academic skills and their perceptions of audit and research prior to and following participation. RESULTS: The group completed its first national clinical study ("STARSurgUK") with 273 student collaborators across 109 hospital centres. Ninety-seven paired pre- and post-study participation responses (35.5%) were received (male = 51.5%; median age = 23). Participation led to increased confidence in key academic domains including: communication with local research governance bodies (p < 0.001), approaching clinical staff to initiate local collaboration (p < 0.001), data collection in a clinical setting (p < 0.001) and presentation of scientific results (p < 0.013). Collaborators also reported an increased appreciation of research, audit and study design (p < 0.001). CONCLUSIONS: Engagement with the STARSurg network empowered students to participate in a national clinical study, which increased their confidence and appreciation of academic principles and skills. Encouraging active participation in collaborative, student-led, national studies offers a novel approach for delivering essential academic training.