The aim of this clinical trial is to evaluate the effect of administering low-dose epinephrine and tranexamic acid on perioperative blood loss, thromboembolic complications, and hospitalization duration in patients undergoing knee joint arthroplasty.

Also aim to evaluate the effect of administering low-dose epinephrine and tranexamic acid on perioperative thromboembolic complications, and hospitalization duration

Patients will be randomly divided into two groups: one receiving intravenous low-dose epinephrine and tranexamic acid, while the other will receive TXA alone as the control. Randomization to be done using a computer-generated table.

The study will be done a superiority clinical trial. with an estimated 24 hour blood loss of 300 ml, with standard deviation of 150 ml. a power of 80% and alpha 5%, an estimated sample size of 80 is needed to detect a difference.

Inclusion Criteria:

• Patients undergoing knee joint arthroplasty.
• Saudi and Non-Saudi Patient.
• Patients who have Complete medical record.

Exclusion Criteria:

• End stage renal disease
• Liver cirrhosis
• Coagulopathy
• Pre-operative Hgb <10 5.
• History of cerebrovascular accident or myocardial infarction in past 12 months.
• History of Heart failure.
• History of arrhythmia.
• History of pheochromocytoma, thyrotoxicosis and glaucoma.
• Pregnancy or breast feeding
• History of Deep venous thrombosis or pulmonary embolism
• Allergy to epinephrine or tranexamic acid