Inclusion criteria:  Patients with knee osteoarthritis who underwent primary TKA; Informed consent has been signed and medical records are complete; No severe varus or valgus deformity of the knee (< 20°).  Exclusion criteria:  Patients undergoing revision knee replacement; patients with rheumatoid arthritis and secondary knee osteoarthritis; Patients with severe valgus deformity(≥ 20°); Taking anticoagulant drugs for a long time in the past, or suffering from the following diseases: Renal insufficiency, liver insufficiency, severe heart disease (or coronary stent implantation within the last 12 months), severe respiratory disease, history of deep vein thrombosis in the lower extremities or a high risk of thrombosis (hereditary/acquired thrombosis), coagulation dysfunction, stroke, and malignancy