The Effect of General Versus Neuraxial Anaesthesia on Bleeding and Thrombotic Outcomes in Neck of Femur Fracture Surgery: A Meta-Analysis

Background: Hip fracture surgery in elderly patients carries significant risks of both bleeding and thrombotic complications. Anaesthetists frequently face a dilemma between neuraxial anaesthesia, which may reduce thrombotic risk but is often limited by contraindications, and general anaesthesia, which is widely applicable but may exacerbate bleeding. Previous reviews have not specifically addressed bleeding and thrombotic outcomes, leaving a critical gap that this meta-analysis seeks to answer. Study objective: To evaluate the effect of neuraxial anaesthesia compared to general anaesthesia on the incidence of bleeding and thrombotic complications in acute neck of femur fracture surgery. Methods: Relevant studies comparing neuraxial and general anaesthetic for hip fracture surgery were searched for through Medline, Embase, Scopus, CINAHL and PubMed. Inclusion criteria were randomised control trials of hip fracture surgery patients aged >16 years with relevant outcome data. In total, 24 randomised control trials were included, with 5479 patients. A meta-analysis was performed using RevMan 5.4 software. The study was registered with PROSPERO ID: CRD42022348039. Outcome measurement: Primary outcomes were intra-operative blood loss, intra- or post-operative blood transfusion and post-operative deep vein thrombosis. Secondary outcomes were post-operative pulmonary embolism, post-operative myocardial infarction and post-operative stroke. Results: Neuraxial anaesthesia reduced deep vein thrombosis incidence by 45% and reduced blood loss by 58 mL, both of which reached statistical significance (p < 0.05). Albeit not reaching statistical significance, neuraxial anaesthesia also had a 35% relative risk reduction in myocardial infarction, and a 35% relative decrease in stroke in current studies published after 2010. Despite practise evolution over the decades, protective neuraxial trends have remained. Conclusions: Patients undergoing acute hip fracture surgery under general anaesthesia have higher volumes of blood loss, without requiring increased blood transfusion. General anaesthesia is also associated with higher thrombotic complications, with a 45% increased relative risk of deep vein thrombosis, compared to neuraxial anaesthesia. Multi-modal thromboprophylaxis is important, as up to a third of DVT cases occur in the non-operative leg. In frail patients with a low cardiopulmonary reserve for bleeding or in high-thrombotic-risk patients, extra consideration and optimisation for neuraxial technique is advised. Future studies on comorbidities and operation type may reveal a subgroup of patients which would benefit from a specific anaesthetic type.