Formation and Development of Deep Vein Thrombosis in Hip Fracture Patients With and Without Anticoagulation

Background: Continuous ultrasound was done on newly admitted hip fracture patients to evaluate post-fracture anticoagulation efficacy, perioperative lower limb deep vein thrombosis timing, and thrombosis distribution/prognosis in those on different thromboprophylaxis. Methods: This randomized clinical trial enrolled patients with fresh hip fractures (age >18 years; injury-to-admission time ≤24 h). Eligible patients without thrombosis on admission ultrasound were randomly assigned in a 2:1 ratio to the anticoagulation group or the non-anticoagulation group. The anticoagulation group received nadroparin calcium (Fraxiparine, 3800 IU/0.4 mL subcutaneously once daily) plus mechanical thromboprophylaxis with an intermittent plantar pressure pump. The non-anticoagulation group received mechanical thromboprophylaxis alone. Bilateral lower extremity venous ultrasound was performed daily throughout hospitalization. Venous blood was collected at four time points (admission, 1 day pre-op, 1 day post-op, 3 days post-op) for routine blood tests and D-dimer measurement. Thrombosis type, occurrence time, location, and laterality were recorded. This intensive ultrasound surveillance protocol was used solely for research purposes and is not the standard. Results: This study included 330 patients (193 females, 137 males), mean age 67.39 ± 16.69 years (18-94 years), injury-to-admission time ≤24 h, mean preoperative waiting time 3.48 ± 1.68 days, mean hospital stay 7.19 ± 2.64 days. There were 178 (53.9%) femoral neck fractures and 152 (46.1%) intertrochanteric and subtrochanteric fractures. Six patients with post-admission proximal thrombosis had pre-procedure inferior vena cava filter implantation; no pulmonary embolism occurred during hospitalization. Anticoagulant group (201 patients): 42 (20.89%) pre-op thrombosis, 81 (40.29%) post-op thrombosis. Non-anticoagulant group (129 patients): 26 (20.15%) pre-op thrombosis, 55 (42.64%) post-op thrombosis. Conclusions: Continuous ultrasound surveillance reveals that days 2–3 post-injury and the first postoperative day represent the periods of highest thrombotic risk in patients with acute hip fractures. However, because most detected DVTs were distal and asymptomatic, and no pulmonary embolism or death occurred in either group, the clinical value of routine, protocol-driven ultrasound screening has yet to be established. Selective screening guided by symptoms or high-risk features may offer a more clinically appropriate strategy. Future studies should determine whether early DVT detection in this population translates into improved patient-important outcomes.