Objectives. Venous thromboembolism (VTE) is a major potential complication following orthopaedic surgery. Subcutaneously administered enoxaparin has been used as the benchmark to reduce the incidence of VTE. However, concerns have been raised regarding the long-term administration of enoxaparin and its possible negative effects on bone healing and bone density with an increase of the risk of osteoporotic fractures. New oral anticoagulants such as rivaroxaban have recently been introduced, however, there is a lack of information regarding how these drugs affect bone metabolism and post-operative bone healing. Methods. We measured the migration and proliferation capacity of mesenchymal stem cells (MSCs) under enoxaparin or rivaroxaban treatment for three consecutive weeks, and evaluated effects on MSC mRNA expression of markers for stress and osteogenic differentiation. Results. We demonstrate that enoxaparin, but not rivaroxaban, increases the migration potential of MSCs and increases their cell count in line with elevated mRNA expression of C-X-C chemokine receptor type 4 (CXCR4), tumor necrosis factor alpha (TNFα), and alpha-B-crystallin (CryaB). However, a decrease in early osteogenic markers (insulin-like growth factors 1 and 2 (IGF1, IGF2), bone morphogenetic protein2 (BMP2)) indicated inhibitory effects on MSC differentiation into osteoblasts caused by enoxaparin, but not by rivaroxaban. Conclusions. Our findings may explain the adverse effects of enoxaparin treatment on bone healing. Rivaroxaban has no significant impact on MSC metabolism or capacity for osteogenic differentiation in vitro. Cite this article: Dr H. Pilge. Enoxaparin and rivaroxaban have different effects on human mesenchymal stromal cells in the early stages of bone healing. Bone Joint Res 2016;5:95–100. DOI: 10.1302/2046-3758.53.2000595

Background. Hitherto, no study has compared blood loss (BL) after different thromoprophylactic regimes (TR). The objective of this study was to quantify and compare BL in total hip arthroplasty (THA) under three different TRs. Methods. Between September 2013 and July 2014, sixty primary, unilateral, same-implant THAs entered a randomised, double-blind clinical trial. The patients were randomised to receive manufacturers' recommended doses of enoxaparin, dabigatran or rivaroxaban. Complete blood counts were obtained preoperatively and on the third day postoperatively. BL was calculated according to the Nadler formula. We also evaluated the occurence of wound healing disturbances (WHDs). All data were analysed using R statistical software. Results. The mean BL and standard deviations were 844 ± 222 ml for enoxaparin, 854 ± 205 ml for dabigatran and 806 ± 227 ml for rivaroxaban. The BL did not significantly differ between groups (Kruskall-Wallis, p=0.92). More WHDs occured in the rivaroxaban group (5/20), compared to enoxaparin (2/20) and dabigatran (3/20). Conclusions. None of the chemical TR is superior to others in terms of reducing the BL. There seems to be more WHDs with the use of oral agents - this finding needs further studies. Level of evidence. 1b (Centre for Evidence Based Medicine, Oxford). Approval. This study was approved by The Medical Centre of Postgraduate Education Ethical Committee. Disclosure. The authors disclose no competing interests

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

Due to working time restrictions a full-shift cross-covering system is commonplace. As more than one surgeon is responsible for trauma admissions in a 24-hour period a complete handover is paramount to ensure continuity of care. The purpose of this audit was to determine whether the introduction of a formal handover/admission form would improve this continuity with regards to prescription of venous thromboembolism (VTE) prophylaxis in hip fracture patients. In Stirling Royal Infirmary chemical VTE prophylaxis for hip fracture patients is 40mg enoxaparin at 6pm unless there is a contraindication. Over a 14-day period we prospectively documented the prescription of VTE prophylaxis and doses missed under the current admissions system. Following this a proforma was introduced that was to be exchanged at handover meetings. The proforma included patients' name/details, admission ward, and tasks to be completed during clerk-in, including VTE prophylaxis prescription. Tasks outstanding at handover had to be documented and completed by the subsequent doctor. Each form was signed and dated by the receiving doctor. We subsequently re-evaluated the prescription of VTE prophylaxis in hip fracture patients. Between 1/12/10-15/12/10, 23 patients were admitted with hip fracture. 12 had appropriate VTE prophylaxis, 6 missed one dose, 4 missed two, and 1 missed three all due to failure of prescription. Following the introduction of the proforma, 12 patients were admitted with hip fractures between 31/12/10-14/1/11. All were prescribed appropriate VTE prophylaxis and missed no doses. 1 patient was on warfarin and had enoxaparin prescribed but withheld until INR< 2.0. After the introduction of a handover form VTE prophylaxis prescription vastly improved. This proforma ensured that all elements of initial management were completed allowing for physician accountability, greater efficacy of handover and continuity of care