Outcome measures
blood loss, bleeding
BLOOD LOSS, BLEEDING, CHRONIC DISEASES, COMPLICATIONS
Age, gender, body mass index (BMI), ASA classification, Kellgren-Lawrence classification, red blood cell count (RBC), hemoglobin concentration (Hb), hematocrit (Hct), platelet count (PLT), prothrombin time (PT), activated partial thromboplastin time (APTT), D-dimer, and chronic diseases were recorded to evaluate comparability between groups. Surgical time, intraoperative fluid volume, and intraoperative urine output were recorded as general intraoperative conditions.Vein blood collection for hemoglobin concentration testing was performed upon completion of surgery. The estimated blood volume was calculated using Nadler formula (Formula *Men: kNote: EBV (ml), estimated total blood volume. H (m): height. W (kg): weight. HbL (g): total hemoglobin loss Hbpre (g/L): preoperative hemoglobin concentration. Hbpost (g/L): postoperative hemoglobin concentration. VL (ml): total blood loss.During surgery, the bleeding condition of the bone-cutting surface was evaluated and graded by the same senior surgeon using the bleeding score method for grading the distal femur bone-cutting surface [Lactate levels (Lac) in arterial blood were measured before and after low-dose NE administration, and the difference (ΔLac) was recorded to assess the perfusion of the patient's systemic organs. All patients were followed up for 3 days after surgery and underwent lower-limb venous Doppler ultrasonography to monitor complications. Transfusion records during hospitalization were documented for both groups of patients.All measurements were performed by an investigator at the indicated time intervals and analyzed by the Clinical Biochemical Department of Fujian Provincial Hospital.