Several experimental models have been used to produce intravascular fat embolism. We have developed a simple technique to induce fat embolism using corn oil emulsified with distilled water to form fatty micelles. Fat embolism was produced by intravenous administration of these fatty micelles in anaesthetised rats, causing alveolar oedema, haemorrhage and increased lung weight. Histopathological examination revealed fatty droplets and fibrin thrombi in the lung, kidney and brain. The arteriolar lumen was filled with fatty deposits. Following fat embolism, hypoxia and hypercapnia occurred. The plasma phospholipase A. 2. , nitrate/nitrite, methylguidanidine and proinflammatory cytokines were significantly increased. Mass spectrometry showed that the main ingredient of corn oil was oleic acid. This simple technique may be applied as a new animal model for the investigation of the mechanisms involved in the fat embolism syndrome

Summary Statement. Pulmonary embolism (PE) after total knee arthroplasty can have a significant impact on patient outcomes and healthcare costs. Efforts to prevent or minimise PE over the last 10 years have not had a significant impact on its occurrence at the national level. Introduction. Pulmonary embolism (PE) is a rare but known potentially devastating complication of total knee arthroplasty (TKA). Significant healthcare resources and pharmaceutical research has been recently focused on preventing this complication but limited data exists regarding the early results of this great effort. The purpose of this study was to assess recent national trends in PE occurrence after TKA and evaluate patient outcomes related to this adverse event. Methods. International Classification of Disease - 9th Revision (ICD-9) procedure codes were used to search the National Hospital Discharge Survey (NHDS) for all patients admitted to US hospitals after primary TKA for each year between 2001 and 2010. ICD-9 diagnosis codes were then used to identify patients from this population who developed an acute PE during the same admission. Data regarding patient demographics, hospitalization length, discharge disposition, deep vein thrombosis, mortality, and hospital size/location were gathered from the NHDS. Trends were evaluated by linear regression with Pearson's correlation coefficient (r) and statistical comparisons were made using Student's t-test, z-test for proportions, and chi-square analysis with a significance level of 0.05. Results. 35,220 patients admitted for a primary TKA were identified. 159 (0.045%) of these patients developed an acute PE during the same admission. After adjusting for fluctuations in annual TKA performed, the development of PE after TKA demonstrated a weak negative correlation with time (r=0.17), insignificantly decreasing from an average rate of 0.049% between 2001–2005 to 0.041% between 2006–2010 (p=0.26). The size of the hospital was found to significantly impact the incidence of PE and primary TKA, with the lowest rate seen in hospitals under 100 beds (0.23%) and the highest rate seen in those with over 500 beds (0.65%, p=0.01). No significant differences in PE incidence were noted based on US region (p=0.38). The mean age of patients with PE was 67.7 years. This group included 54 men and 105 women. The non-PE group had a mean patient age that was insignificantly lower at 66.6 years (p=0.21) and included 12,450 men and 22,611 women. Gender was also not significantly different (p=0.68) between those with PE and those without PE. The number of medical co-morbidities was significantly higher in those with PE (mean 6.42 diagnoses) than those without PE (mean 4.89 diagnoses, p<0.01). Average hospitalization length also varied based on PE status, with significantly longer stays for those with PE (8.2 days, range 2–53) compared to those without PE (3.7 days, range 1–95, p<0.01). The rate of deep vein thrombosis was higher in the PE group (12.7%) versus the non-PE group (0.48%, p<0.01). Mortality was also significantly higher for the PE group (3.9%) compared to the non-PE group (0.09%, p<0.01). Discharge disposition did not significantly vary based on PE status, with 61.5% of PE and 64.0% of non-PE patients able to go directly home (p=0.59) after their inpatient stay. Discussion/Conclusion. This study demonstrates that PE can have a significant impact on patient outcomes and healthcare costs, with an associated 43-fold increase in mortality and a doubling of the inpatient admission duration. Additionally, although the risk of PE after primary TKA remains rare, it still persists. Efforts to prevent or minimise this complication over the last 10 years have not had a significant impact on its occurrence at the national level. This risk of PE appears to be greatest in patients with multiple medical co-morbidities and established DVTs. Interestingly, the PE rate also demonstrated variability based on hospital size. The reasons for this are not clear, but we suspect larger hospitals are more likely to be tertiary-care centers and thus care for more medically-complex patients

Introduction

The objective of this study was to identify fat emboli in the arterioles of the femoral bone marrow by Scanning Electron Microscopy (SEM) after glucocorticoid administration.

Revision knee arthroplasty is a complex procedure with the number and cost of knee revision procedures performed per year expected to rise. Few studies have examined adverse events following revision arthroplasty. The objective of this study was to determine rates of serious adverse events in patients undergoing revision knee arthroplasty with consideration of the indication for revision (urgent versus elective indications) and to compare these with primary arthroplasty and re-revision arthroplasty. Patients undergoing primary knee arthroplasty were identified in the UK Hospital Episode Statistics. Subsequent revision and re-revision arthroplasty procedures in the same patients and same knee were identified. The primary outcome was 90-day mortality and a logistic regression model was used to investigate factors associated with 90-day mortality and secondary adverse outcomes including infection (undergoing surgery), pulmonary embolism, myocardial infarction, stroke. Urgent indications for revision arthroplasty were defined as infection or fracture, and all other indications were included in the elective indications cohort. 939,021 primary knee arthroplasty cases were included of which 40,854 underwent subsequent revision arthroplasty, and 9,100 underwent re-revision arthroplasty. Revision surgery for elective indications was associated with a 90-day rate of mortality of 0.44% (135/30,826; 95% CI 0.37-0.52) which was comparable to primary knee arthroplasty (0.46%; 4,292/939,021; 95% CI 0.44-0.47). Revision arthroplasty for infection, however, was associated with a much higher mortality of 2.04% (184/9037; 95% CI 1.75-2.35; odds ratio [OR] 3.54; 95% CI 2.81-4.46), as was revision for periprosthetic fracture at 5.25% (52/991; 95% CI 3.94-6.82; OR 6.23; 95% CI 4.39-8.85). Higher rates of pulmonary embolism, myocardial infarction, and stroke were also observed in the infection and fracture cohort. These findings highlight the burden of complications associated with revision knee arthroplasty. They will inform shared decision-making for patients considering revision knee arthroplasty for elective indications. Patients presenting with infection of a knee arthroplasty or a periprosthetic fracture are at very high risk of adverse events. It is important that acute hospital services and tertiary referral centres caring for these patients are appropriately supported to ensure appropriate urgency and an anticipation for increased care requirements

Abstract. BACKGROUND. The effectiveness of anti-embolic graduated compression stockings (GCSs) has recently been questioned. The aim of this study is to systematically review all the relevant randomised controlled trials published to date. PATIENTS AND METHODS. We systematically reviewed all the randomised controlled trials comparing anti-embolism stockings with no stockings. We searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and CINAHL, Cochrane Musculoskeletal Injuries Group specialized register and the reference lists of articles as well as hand search results. Trials were independently assessed and data for the main outcome measures; deep vein thrombosis (DVT), pulmonary embolism and skin ulceration, were extracted by two reviewers. RESULTS. A total of 26 relevant RCTs involving 8279 participants were systematically reviewed. Theoccurrence of deep vein thrombosis was 306/4159(7.3%) with the stocking to 492/4120(11.9%) without the stockings (RR 0.49, 95% CI 0.39–0.62). The occurrence of pulmonary embolism was also reduced from 1.2% go 0.7% (95% 0.33–0.92). This initial finding was unsound due to the potential underreporting of negative studies and the subsequent changes to clinical practice. For the three large contemporary studies involving 5171 participants, these failed to show any statistically significant reduction in thrombosis, with DVT confirmed in 158(6.1%) participants in those allocated to stocking, as opposed to 171(6.6%) in the control group. CONCLUSION. The current recommendations regarding the use of GCSs need to be reconsidered, as their effectiveness at reducing the occurrence of post-operative DVT is minimal at best, based on the current evidence and clinical practices

Introduction and Objective. The effectiveness of anti-embolic graduated compression stockings (GCSs) has recently been questioned. The aim of this study is to systematically review all the relevant randomised controlled trials published to date. Materials and Methods. We systematically reviewed all the randomised controlled trials comparing anti-embolism stockings with no stockings. We searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and CINAHL, Cochrane Musculoskeletal Injuries Group specialized register and the reference lists of articles as well as hand search results. Trials were independently assessed and data for the main outcome measures; deep vein thrombosis (DVT), pulmonary embolism and skin ulceration, were extracted by two reviewers. Results. A total of 26 relevant RCTs involving 8279 participants were systematically reviewed. The occurrence of deep vein thrombosis was 306/4159 (7.3%) with the stocking to 492/4120 (11.9%) without the stockings (RR 0.49, 95% CI 0.39–0.62). The occurrence of pulmonary embolism was also reduced from 1.2% to 0.7% (95% 0.33–0.92). This initial finding was unsound due to the potential underreporting of negative studies and the subsequent changes to clinical practice. For the three large contemporary studies involving 5171 participants, these failed to show any statistically significant reduction in thrombosis, with DVT confirmed in 158 (6.1%) participants in those allocated to stocking, as opposed to 171 (6.6%) in the control group. Conclusions. The current recommendations regarding the use of thrombo-embolic stockings need to be reconsidered, as their effectiveness at reducing the occurrence of post-operative deep vein thrombosis is minimal at best, based on the current evidence and clinical practices

The e-scooter trial was part of a wider initiative from the Department for Transport in response to COVID pandemic. New emergency legislation was introduced in 2020 to make e-scooters legal in the UK for the first time. This scheme was launched in our county from September 2020. The aim of this case series was to identify the types of Orthopedic injuries resultant from electric scooter transport that presented to our District General Hospital over a 16-month period between September 2020 and December 2021. This study involved retrospective collection of data from electronic hospital records. Data on demographics, laterality, date of injury, type of injury, treatment, HDU/ITU admissions, mortality, and operating time were collected to characterize the types of e-scooter-related injuries and to investigate the frequency of such injuries over the duration of our search. A total of 79 orthopedic patients identified with electric scooter injuries between September 2020 and December 2021. 78.5% were males and the mean age was 30.1 years. Summer months accounted for most of the injuries. 17 patients required inpatient care. 23 patients required surgical intervention and a total of 29 surgeries were performed in our hospital. This accounted for a total surgical time of 2088 minutes. One patient admitted with shaft of femur fracture developed pulmonary embolism after the definitive operation and died in HDU. Electric scooters provide a space efficient, affordable, environmentally friendly mode of transportation which reduce the urban congestion and parking issues. This study demonstrates an increasing frequency of significant orthopedic injury associated with e-scooter use treated at our centre over the course of 16 months. This small series underlines an important problem given that this increase has occurred after the start of the electric scooter trial. Legalization might result in further increase in the incidence of injury

We investigated factors associated with postoperative lipiduria and hypoxemia in patients undergoing surgery for orthopedic fractures. We enrolled patients who presented to our emergency department due to traumatic fractures between 2016 and 2017. We collected urine samples within 24 hours after the patients had undergone surgery to determine the presence of lipiduria. Hypoxemia was defined as an SpO2 <95% determined with a pulse oximeter during the hospitalization. Patients’ anthropometric data, medical history, and laboratory test results were collected from the electronic medical record. Logistic regression analyses were used to determine the associations of clinical factors with postoperative lipiduria and hypoxemia with multivariate adjustment. A total of 144 patients were analyzed (mean age 51.3 ± 22.9 years, male 50.7%). Diabetes (odd ratio 3.684, 95% CI 1.256-10.810, p=0.018) and operation time (odd ratio 1.005, 95% CI 1.000-1.009, p=0.029) were independently associated with postoperative lipiduria, while age (odd ratio 1.034, 95% CI 1.003-1.066, p=0.029), body mass index (odd ratio 1.100, 95% CI 1.007-1.203, p=0.035), and operation time (odd ratio 1.005, 95% CI 1.000-1.010, p=0.033) were independently associated with postoperative hypoxemia. We identified several factors independently associated with postoperative lipiduria and hypoxemia in patients with fracture undergoing surgical intervention. Operation time was associated with both postoperative lipiduria and hypoxemia, and we recommend that patients with prolonged operation for fractures should be carefully monitored for clinical signs related to fat embolism syndrome

Introduction. As per national guidelines for Ankle fractures in the United Kingdom, fractures considered stable can be treated with analgesia, splinting and allowed to weight bear as tolerated. The guidelines also suggest further follow-up not mandatory. This study was aimed at evaluating the current clinical practice of managing stable ankle fractures at a university hospital against national guidelines. Method. The study was undertaken using retrospectively collected data, the inclusion criteria being all adults with stable ankle fracture pattern treated non-operatively between December 2022 and April 2023. Collected data included age of patient, date of injury, type of immobilization, number of clinical visits and any complications. Results. 41 cases were identified and analyzed. The mean age of the cohort was 49.8 years (Standard deviation 20.01). Twelve percent (n = 5) were reviewed in clinic, treated and discharged as stable Weber B type fracture pattern as per national guidelines after the first visit. About 52% (n = 21) were seen in clinic twice before discharge, first visit between 1-2 weeks and the last clinic visit between 5-7 weeks. About a third of patients (30%, n = 12) were seen in clinic on more than two occasions. At the first clinic visit 87% (n = 36) were given a boot and allowed to weight bear as tolerated. Two patients were diagnosed with deep vein thrombosis/pulmonary embolism during the treatment duration. Three patients had extended duration of follow up for ongoing symptoms. None discharged after first or second visit needed surgery for displaced or malunited fracture. Conclusion. Patients discharged from clinic after first or second visit did not need any further surgery. As per national guidelines, patients deemed stable weber B lateral malleolus fracture pattern after weight bearing radiograph can be treated safely with a weight bearing walking boot with no further follow up

Introduction and Objective. Ankle fractures are common and affect young adults as well as the elderly. An unstable ankle fracture treatment typically involves surgical fixation, immobilisation, and modified weight-bearing for six weeks. Non-weight bearing (NWB) cast immobilisation periods were used to protect the soft tissue envelope and osteosynthesis. This can have implications on patient function and may reduce independence, mobility and return to work. Newer trends in earlier mobilisation compete with traditional NWB doctrine, and weak consensus exists as to the best postoperative strategy. The purpose of this trial is to investigate the safety and efficacy of immediate weight-bearing (IWB) and range of motion (ROM) exercise regimes following ORIF of unstable ankle fractures with a particular focus on functional outcomes and complication rates. Materials and Methods. A pragmatic randomised controlled multicentre trial, comparing IWB in a walking boot and ROM within 24 hours versus non-weight-bearing (NWB) and immobilisation in a cast for six weeks, following ORIF of all types of unstable adult ankle fractures (lateral malleolar, bimalleolar, trimalleolar with or without syndesmotic injury). The exclusion criteria are skeletal immaturity and tibial plafond fractures. The primary outcome measure is the functional Olerud-Molander Ankle Score (OMAS). Secondary outcomes include wound infection (deep and superficial), displacement of osteosynthesis, the full arc of ankle motion (plantar flexion and dorsal flection), RAND-36 Item Short Form Survey (SF-36) scoring, time to return to work and postoperative hospital length of stay. Results. We recruited 160 patients with an unstable ankle fracture. Participants’ ages ranged from 15 to 94 years (M = 45.5, SD = 17.2), with 54% identified as female. The mean time from injury to surgical fixation was 1.3 days (0 to 17 days). Patients in the immediate weight-bearing group had a 9.5-point higher mean OMAS at six weeks postoperatively (95% CI 1.48, 17.52) P = 0.021. The complications rate was similar in both groups. The rate of surgical site infection was 4.3%. One patient had DVT, and another patient had a pulmonary embolism; both were randomised to NWB. Length of hospital stay (LOS) was 1 ± 1.5 (0, 12) for the IWB group vs 1.5 ± 2.5 (0, 19) for the NWB group. Conclusions. There is a paucity of quality evidence supporting the postoperative management regimes used most commonly in clinical practice. To our knowledge, immediate weight-bearing (IWB) following ORIF of all types of unstable ankle fractures has not been investigated in a controlled prospective manner in recent decades. In this large multicentre, randomised controlled trial, we investigated immediate weight-bearing following ORIF of all ankle fracture patterns in the usual care condition using standard fixation methods. Our result suggests that IWB following ankle fracture fixation is safe and resulted in a better functional outcome. Once anatomical reduction and stable internal fixation is achieved, we recommend IWB in all types of ankle fractures in a compliant patient

Abstract. Objectives. Our study evaluates financial impact to the Best Practice Tariff (BPT) of hip fracture patients on Novel Oral Anti-Coagulant (NOAC) medication. Since their approval by NICE for the prevention of stroke and systemic embolism in non-valvular atrial fibrillation, the incidence of hip fracture patients admitted to hospitals on NOAC medication (e.g. rivaroxiban, apixaban) has been increasing. BPT for hip fractures has two components: a base tariff and a conditional top-up tariff of £1,335 per patient (applied to patients of 60 years of age). For the top-up tariff, six criteria must be met, of which time-to-surgery within 36 hours is one. Our department currently recommends withholding NOAC medication and delaying surgery for at least 48 hours as per our Trust's haematology guidelines to reduce intra-operative bleeding risk. Therefore, the conditional top-up tariff cannot be claimed for these patients. Method. A retrospective review of our Trust hip fracture patients over 60 years of age admitted during 2019 on NOAC medication using National Hip Fracture Database (NHFD). Results. 545 hip fracture patients had operative treatment at our Trust during the one-year period of 2019. 31 of these patients were admitted on NOAC medication, and therefore had to stop the NOAC and wait for at least 48 hours before having surgery. This translates to a potential hip fracture BPT loss of £41,385 in 2019, as the conditional top-up tariff could not be claimed. Conclusion. This study illustrates the large financial impact to BPT that hip fracture patients admitted on NOAC medications has at our Trust. It raises the argument as to whether the BPT should allow for an increased length of time until surgery for such patients, to allow safe surgical treatment with reduced bleeding risk. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

The Hospital (Trust) guidelines generally recommend 40mg of Low molecular weight heparin (LMWH) twice daily (BD) for all patients over 100kg for those undergoing total hip (THR) and knee replacements (TKR) respectively. British National Formulary (BNF) recommends 40mg of LMWH once daily (OD) for all patients regardless of their overall weight or body mass index (BMI). We evaluated the outcome of prophylactic LMWH dosage for patients undergoing THR and TKR by monitoring surgery related venous-thromboembolic events up to a minimum of three months after surgery. A retrospective audit was carried out after obtaining institutional approval and all consecutive elective patients weighing over 100kg and undergoing THR and TKR were included. All patients were followed up for a minimum of 3 months after their operation to investigate the dose of prophylactic LMWH received, and whether they had developed any venous thromboembolic events (VTE) post operatively. This was done using a combination of electronic notes, drug charts and deep venous thrombosis (DVT) or computed tomography pulmonary angiogram (CTPA) reports on the hospital/trust database. A total of 53 patients underwent elective THR (18) and TKR (35) between the period of March 2017 and September 2017. Forty-four patients received 40 mg OD and 9 patients had 40 mg BD. None of the patients developed a confirmed DVT or pulmonary embolism in the 3 months following surgery regardless of the dose received. We demonstrate that there is no clinical benefit in having patients over 100kg on twice daily LMWH with the aim of preventing post-op thromboembolic complications. This conclusion is in line with the BNF recommendations for VTE prophylaxis

Introduction. The BOAST (British Orthopaedic Association Standards for Trauma) guidelines do advise that open pilon fractures amongst other open lower limb fractures need to be treated at a specialist centre with Orthoplastic care. The purpose of this study was to determine clinical outcomes in patients with open pilon fractures treated as per BOAST guidelines including relatively aggressive bone debridement. Methods. A retrospective analysis of a single surgeon series of open pilon fractures treated between 2014 and 2019 was conducted. Injuries were graded according to the Gustillo-Anderson classification and all patients were included for the assessment of the rate of infection and fracture healing. Functional outcome assessment was performed in all patients according to the American Orthopedic Foot and Ankle Score (AOFAS) at 6 months after definitive surgery. Initial wound with bone debridement and application of a spanning external fixator was performed within an average of 13.5 (Range: 3–24) hours. Fixation with FWF (Fine Wire Frame) was performed when the wound was healed, with the mean time from primary surgery to application of FWF being 24.5 (Range: 7–60) days. Results. There was a total of 20 patients including 16 males and 4 females. The mean age was 50.45 (Range: 16–88) years. Follow-up was for an average of 23.2 (Range: 5–51) months. There were 3 patients with Gustilo Type I injuries, 6 with Type II, 4 Type with type IIIa and 7 with Type IIIb injuries. Average time to bone union was 9.3 (Range: 2–18) months. The mean AOFAS score was 66 (Range: 15–97) points. TSF was used on 18 patients, while 2 patients had an Ilizarov frame. A corticotomy was performed on 4 patients with critical bone defect post debridement, while 2 patients had Stimulan beads with antibiotics. There was 1 case (5%) of deep infection and 9 cases (45%) of superficial infection. There were also 2 cases (10%) of non-union which required bone grafting from their femur using a RIA (Reamer Irrigation Aspirator). Other complications included 1 case of acute compartment syndrome, 1 case of pulmonary embolism, 1 case of necrotic skin and 1 case of amputation. Conclusion. Results of our study suggests that the use of staged wound debridement including relatively aggressive bone debridement in conjunction with antibiotics, external fixators and patient tailored conversion from spanning external fixator to fine wire frame achieves low rates of wound infection and complications for patients with open pilon fractures

Venous Thromboembolism (VTE) prophylaxis is an essential part of orthopaedic surgeries in preventing life-threatening thromboembolic events such as Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE). Orthopaedic surgery has the highest incidence rate of thromboembolic events as compared to any other surgical specialities, making it an essential component in managing any orthopaedic case. At Queen's Medical Centre (QMC), a major trauma centre in the United Kingdom (UK), sees up to 750 NOF fracture cases annually, making it one of the busiest trauma and orthopaedic centres in the UK. Our study aims to evaluate how VTE Prophylaxis is conducted in a UK Major Trauma Centre for NOF and pelvic fragility fractures and how human factors can improve its efficacy. The Nottingham University Hospitals (NUH) Trust has implemented new guidelines from August 2019 that patients with fragility fractures such as NOF and pelvic fractures are prescribed with 28 days VTE prophylaxis with Enoxaparin, or their own anti-coagulants if risk of thrombosis exceed the risk of bleeding. This is an adaptation from the trust to align their guidelines closer to the NICE 2018 guidelines. We will be evaluating the initial compliance of VTE Prophylaxis, identify and utilise human factors, then re-analyse the department after implementing interventions on the same batch of junior doctors working in the department. Data of 100 patients with fragility fractures were collected, 50 consecutive patients in the pre-intervention window during August 2019 and 50 in the post-intervention window during November 2019. The pre-intervention data had 43 NOF and 7 Pelvic fractures. Our study showed that 93% of NOF fracture and 100% of pelvic fracture received the correct course of VTE prophylaxis. The data was presented at the local department junior doctor academic session. Three simple human factor interventions were implemented over the course of September and October: Education to the trauma and orthopaedic department on the new guideline, extended VTE labels on drug charts for patients with fragility fractures, VTE reminder labels at doctors' stations. Another 50 consecutive patients' data were collected during November 2019. Data shows that 97.8% of NOF (p>0.05) and 60% of pelvic fracture (p>0.05) received the correct course of VTE prophylaxis. Our data has shown an increase in correct VTE prescription for NOF fracture patients, which is the main bulk of our fragility fracture patients whilst we see a drop in pelvic fracture patients. Due to the limited time frame of four months where junior doctors in the UK rotate between specialities, we are only able to collect data during the first month, implement interventions between datasets and collect data on the final month of the four-month rotation. A future bigger study might provide a more significant result on the department. We believe that the key to achieving 100% VTE prophylaxis in the T&O department is optimising human factors, educating junior doctors, who are not orthopaedic trained, with sufficient information of the guidelines, and evidence of the risk and benefits of providing prolonged VTE prophylaxis for orthopaedic patients. In conclusion, we found that QMC, a major trauma centre with high patient volume and turnover, has a high level of compliance with VTE prophylaxis for fragility fractures and it is imperative that utilising human factors will inch the department closer to its goal of 100% VTE compliance

Objectives. We have increased the dose of tranexamic acid (TXA) in our enhanced total joint recovery protocol at our institution from 15 mg/kg to 30 mg/kg (maximum 2.5 g) as a single, intravenous (IV) dose. We report the clinical effect of this dosage change. Methods. We retrospectively compared two cohorts of consecutive patients undergoing total hip arthroplasty (THA) or total knee arthroplasty (TKA) surgery in our unit between 2008 and 2013. One group received IV TXA 15 mg/kg, maximum 1.2 g, and the other 30 mg/kg, maximum 2.5 g as a single pre-operative dose. The primary outcome for this study was the requirement for blood transfusion within 30 days of surgery. Secondary measures included length of hospital stay, critical care requirements, re-admission rate, medical complications and mortality rates. Results. A total of 1914 THA and 2537 TKA procedures were evaluated. In THA, the higher dose of TXA was associated with a significant reduction in transfusion (p = 0.02, risk ratio (RR) 0.74, 95% confidence interval (CI) 0.58 to 0.96) and rate of re-admission (p < 0.001, RR 0.50, 95% CI 0.35 to 0.71). There were reductions in the requirement for critical care (p = 0.06, RR 0.55, 95% CI 0.31 to 1.00), and in the length of stay from 4.7 to 4.3 days (p = 0.02). In TKA, transfusion requirements (p = 0.049, RR 0.64, 95% CI 0.41 to 0.99), re-admission rate (p = 0.001, RR 0.56, 95% CI 0.39 to 0.80) and critical care requirements (p < 0.003, RR 0.34, 95% CI 0.16 to 0.72) were reduced with the higher dose. Mean length of stay reduced from 4.6 days to 3.6 days (p < 0.01). There was no difference in the incidence of deep vein thrombosis, pulmonary embolism, gastrointestinal bleed, myocardial infarction, stroke or death in THA and TKA between cohorts. Conclusion. We suggest that a single pre-operative dose of TXA, 30 mg/kg, maximum 2.5g, results in a lower transfusion requirement compared with a lower dose in patients undergoing elective primary hip and knee arthroplasty. However, these findings should be interpreted in the context of the retrospective non-randomised study design. Cite this article: R. J. M. Morrison, B. Tsang, W. Fishley, I. Harper, J. C. Joseph, M. R. Reed. Dose optimisation of intravenous tranexamic acid for elective hip and knee arthroplasty: The effectiveness of a single pre-operative dose. Bone Joint Res 2017;6:499–505. DOI: 10.1302/2046-3758.68.BJR-2017-0005.R1

This edition of Cochrane Corner looks at some of the work published by the Cochrane Collaboration, covering pharmacological interventions for the prevention of bleeding in people undergoing definitive fixation or joint replacement for hip, pelvic, and long bone fractures; interventions for reducing red blood cell transfusion in adults undergoing hip fracture surgery: an overview of systematic reviews; and pharmacological treatments for low back pain in adults: an overview of Cochrane Reviews

The Cochrane Collaboration has produced five new reviews relevant to bone and joint surgery since the publication of the last Cochrane Corner These reviews are relevant to a wide range of musculoskeletal specialists, and include reviews in Morton’s neuroma, scoliosis, vertebral fractures, carpal tunnel syndrome, and lower limb arthroplasty.

The stress response to trauma is the summation of the physiological response to the injury (the ‘first hit’) and by the response to any on-going physiological disturbance or subsequent trauma surgery (the ‘second hit’). Our animal model was developed in order to allow the study of each of these components of the stress response to major trauma. High-energy, comminuted fracture of the long bones and severe soft-tissue injuries in this model resulted in a significant tropotropic (depressor) cardiovascular response, transcardiac embolism of medullary contents and activation of the coagulation system. Subsequent stabilisation of the fractures using intramedullary nails did not significantly exacerbate any of these responses

Summary Statement. Navigated total knee arthroplasty (TKA) is becoming increasingly popular in the United States. Compared to traditional unnavigated TKA, the use of navigation is associated with decreased blood transfusions and shorter hospital stays. Introduction. Navigated total knee arthroplasty (TKA) is a recent modification to standard TKA with many purported benefits in regards to component positioning. Controversy currently exists though regarding its clinical benefits. The purpose of this study was to assess recent national trends in navigated and unnavigated total knee arthroplasty and to evaluate perioperative outcomes for each group. Methods. International Classification of Disease - 9th Revision (ICD-9) procedure codes were used to search the National Hospital Discharge Survey (NHDS) for all patients admitted to US hospitals after navigated and unnavigated TKA for each year between 2005 and 2010. Data regarding patient demographics, hospitalization length, discharge disposition, blood transfusions, deep vein thrombosis, pulmonary embolism, mortality, and hospital location were gathered from the NHDS. Trends were evaluated by linear regression with Pearson's correlation coefficient (r) and statistical comparisons were made using Student's t-test, z-test for proportions, and chi-square analysis with a significance level of 0.05. Results. 22,443 patients admitted for TKA were identified. 578 (2.6%) of these patients had a TKA utilizing navigation. After adjusting for fluctuations in annual TKA performed, the use of navigation in TKA demonstrated a strong positive correlation with time (r=0.71), significantly increasing from an average utilization rate of 2.2% between 2005–2007 to 3.2% between 2008–2010 (p<0.01). The location of the hospital was found to significantly impact the utilization of navigation, with the lowest rate seen in the Midwest region (2.0%) of the US and the highest rate seen in the South region (3.0%). The mean age of navigated patients was 66.0 years. This group included 211 men and 367 women. The unnavigated group had a mean patient age that was insignificantly higher at 66.4 years (p=0.37) and included 7,815 men and 14,047 women. Gender was also not significantly different (p=0.71) between those with navigated TKA and those with unnavigated TKA. The number of medical co-morbidities was significantly higher in those with navigation (mean 5.4 diagnoses) than those without navigation (mean 5.1 diagnoses, p=0.01). Average hospitalization length also varied based on navigation status, with significantly shorter stays for those with navigation (3.3 days, range 1–11) compared to those without (3.6 days, range 1–73, p<0.01). The rate of blood transfusion was significantly lower in the navigated group (13.0%) versus the unnavigated group (17.4%, p<0.01). There was no difference in the rate of deep vein thrombosis (0.69% vs 0.53%, p=0.64) or pulmonary embolism (0.17% vs 0.47%, p=0.10). Mortality was also not significantly different for navigated TKA (0.17%) when compared to unnavigated TKA (0.08%, p=0.61). Discharge disposition did not significantly vary based on navigation status either, with 65.5% of navigated patients and 67.0% of unnavigated patients able to go directly home (p=0.55) after their inpatient stay. Discussion/Conclusion. This study demonstrates that the use of navigated TKA in the US is rising. Additionally, despite having more medical co-mobidities, the navigated population required less blood transfusions and shorter lengths of stay. Interestingly, navigation utilization demonstrated variability based on hospital region. The reasons for this are not immediately clear, but may be related to differences in regional training