Extended Post-operative Oral TXA in Primary THA

The goal of this clinical trial is to learn if extended post-operative oral tranexamic acid (TXA) - a medication that reduces bleeding by slowing the breakdown of blood clots - can improve functional recovery following surgery in adults undergoing primary total knee or hip arthroplasty for osteoarthritis. The main question it aims to answer is: Does extended post-operative oral TXA improve functional outcomes at 6 weeks post-operatively compared to standard perioperative TXA alone? Researchers will compare patients receiving extended oral TXA to patients receiving matching placebo capsules on the same schedule to see if the extended TXA regimen reduces blood loss, improves early functional outcomes, and reduces pain without increasing complication rates. Participants will receive standard perioperative oral TXA (1.95 g) prior to surgical incision, along with standard VTE prophylaxis. They will be randomly assigned to receive either oral TXA or matching placebo capsules once daily on post-operative days 1, 2, and 3. Participants will attend follow-up visits at 2, 6, and 12 weeks post-operatively to complete functional outcome questionnaires, pain assessments, and - for knee replacement patients - range of motion measurements.

Inclusion Criteria: * Age ≥18 years * Undergoing primary total knee arthroplasty (TKA) or total hip arthroplasty (THA) for osteoarthritis * Ability to provide written informed consent * Willingness to comply with study protocol Exclusion Criteria: * History of venous thromboembolism (DVT or PE) * Active malignancy * Allergy or contraindication to tranexamic acid (TXA) * Post-operative anticoagulation therapy other than aspirin * History of color blindness or retinal disease