Total knee arthroplasty is a common operation performed to relieve pain and improve movement in patients with severe knee joint disease, such as osteoarthritis, rheumatoid arthritis, post-traumatic arthritis, or osteonecrosis. However, blood loss after surgery remains an important concern because it may lead to a fall in hemoglobin level and increase the need for blood transfusion. Blood transfusion may be necessary in some patients, but it also carries additional risks and cost. One practice that may influence postoperative blood loss is the use of a surgical drain. A drain is commonly placed at the end of surgery to remove blood and fluid from the operated area, but its benefit in total knee arthroplasty remains uncertain. Some studies suggest that drains may reduce blood collection inside the joint, whereas others suggest that they may increase overall blood loss by preventing the natural pressure effect that helps stop bleeding.

This randomized clinical trial is being conducted to compare hemoglobin drop and blood transfusion requirement in patients undergoing primary unilateral total knee arthroplasty with or without drain insertion. A total of 102 patients will be enrolled and randomly allocated into two equal groups. In Group A, a closed suction drain will be inserted at the end of surgery. In Group B, no drain will be used. All operations will be performed using a standardized surgical technique, and all patients will receive similar perioperative care, including tranexamic acid, analgesia, thromboprophylaxis, and rehabilitation.

Hemoglobin levels will be measured before surgery and again at 24 and 48 hours after surgery. The main outcomes will be the amount of hemoglobin drop after surgery and whether blood transfusion is required. Blood transfusion will be given according to the predefined hospital protocol when hemoglobin falls below 8 g/dL. The study hypothesis is that there is a significant difference in postoperative hemoglobin drop and blood transfusion requirement between patients undergoing primary knee arthroplasty with drain insertion and those undergoing surgery without drain insertion.

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.