Patients With Pelvic and Acetabular Fractures Demonstrate High Risk for Venous Thromboembolism, Prolonged Impaired Fibrinolysis, and Platelet-Dominant Hypercoagulability

The risk for venous thromboembolism (VTE) after pelvic and acetabular fractures remains high, supporting a need for appropriate thromboprophylaxis to reduce the risk of these potentially life-threatening events. Thrombelastography (TEG) is a whole-blood assay that provides a comprehensive analysis of hemostasis from clot initiation to fibrinolysis. This study aimed to use serial TEG analysis to identify those at increased risk for VTE and to determine the different phases of hypercoagulability after a pelvic or acetabular fractures. This single-centre prospective cohort study enrolled consecutive adult patients requiring pelvic and acetabular fracture fixation who underwent serial TEG analysis until 12-weeks post-operatively. Hypercoagulability was defined as Maximal Amplitude (MA; a measure of platelet contribution to maximal clot strength) of 65mm or greater. The most common thromboprophylaxis regimen was low-molecular weight heparin for 28 days. Wilcoxon tests compared MA values and the hypercoagulability threshold at each timepoint to define the duration of hypercoagulable state. Impaired fibrinolysis (inability to breakdown clot) was defined as a 30-minute lysis time (LY-30) 0.05). Patients with pelvic and acetabular fractures demonstrated early and persistently impaired fibrinolysis (mean pre-operative LY-30=0.47; POD5 LY-30=0.06, 2-week LY-30=0.13; 4-week LY-30=0.26). Patients with pelvic and acetabular fractures also demonstrated a prolonged platelet-dominant hypercoagulability, with 97% demonstrating elevated MA above the threshold at two weeks (median=71.3), 69% remained hypercoagulable at four weeks (median=65.9mm), and 27% at six weeks (median= 64.6mm). This study supports that patients with pelvic and acetabular fractures remain at very high VTE risk due, at least in part, to impaired fibrinolysis (reduced clot breakdown). This large prospective cohort of patients requiring pelvic or acetabular fracture surgery identified trends in post-operative hypercoagulability for the first time. The prolonged platelet-dominant hypercoagulability suggests that extended antiplatelet thromboprophylaxis may be beneficial. Further research is warranted to investigate impaired fibrinolysis and inflammatory-mediated hypercoagulability to help inform future novel therapeutic targets for VTE risk reduction.