Knee surgery drain debate: new study compares blood loss with and without drain

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Age between 50 and 80 years. * Both male and female patients. * Diagnosed with: * Primary knee osteoarthritis. * Rheumatoid arthritis. * Arthritis following trauma. * Osteonecrosis, or avascular necrosis. * Unilateral primary total knee arthroplasty (TKA) is necessary due to severe knee pain, stiffness, and non-responsiveness to conservative treatment. * Patients with a Knee Society Score (KSS) of ≤60 are considered to have functional limitations, which are characterized as a severe impairment in activities of daily living (ADLs) related to knee disease. * Preoperative hemoglobin ≥10 g/dL to ensure comparable baseline hemoglobin levels across groups. * BMI between 18.5 and 35 kg/m² to exclude extremes of underweight or morbid obesity. Exclusion Criteria: * Patients undergoing revision TKA due to implant failure, infection, or periprosthetic fractures. * Individuals with aberrant coagulation parameters (INR \>1.5, extended PT/aPTT) or inherited or acquired bleeding diseases (such as hemophilia or von Willebrand disease). * Patients receiving antiplatelet therapy (ticagrelor, clopidogrel) or long-term anticoagulants (warfarin, DOACs) within seven days of surgery. * Individuals with sickle cell disease, thalassemia, or chronic anemia (Hb \<10 g/dL). * Individuals with severe COPD, pulmonary hypertension, NYHA Class III or IV heart failure, or a history of DVT/PE within the last six months. * Severe chronic kidney disease (CKD) stage 4/5 (eGFR \<30 mL/min/1.73m²) or severe hepatic dysfunction (Child-Pugh Class C, AST/ALT \>3×normal, bilirubin \>2 mg/dL). * Patients with active systemic infections (sepsis, tuberculosis, HIV/AIDS, hepatitis B/C, osteomyelitis). * Patients with a history of thromboembolic events (DVT/PE/stroke within 12 months) or contraindications to tranexamic acid (TXA). * Pregnant or lactating women.