Our study will compare the use of continuous saphenous nerve block performed at the adductor canal in addition to Local Infiltration Analgesia (LIA) versus a Sham block in addition to LIA for total knee replacement. The investigators hypothesize that the saphenous nerve block performed at the level of the adductor canal in addition to LIA provides better pain relief than the LIA alone without significantly compromising muscle strength and physiotherapy, enabling patients to mobilize early with reduced opioid consumption and les side effects.

The investigators will enroll a total of 40 patients (20 patients will receive continuous saphenous nerve block in addition to LIA and 20 will receive the sham block and LIA). Until discharge, the investigators will record patients' pain scores, opioid consumption, side effects and physical therapy progress.

If our study proves that the continuous saphenous nerve block in addition to LIA can effectively reduce postoperative pain scores to an acceptable level with better physical therapy progress and less opioid consumption, it could be seen as a more attractive alternative to LIA alone or other traditionally used methods of postoperative pain control that compromises muscle strength and physiotherapy.

Inclusion Criteria:

• ASA I-III
• Age: 40-75
• Unilateral TKA
• Use of Spinal anesthesia

Exclusion Criteria:

• Allergy to any of the study medications
• Intolerance to morphine
• Contraindication to a spinal anesthetic
• Intraoperative use of any volatile anesthetic
• Chronic opioid use
• ASA Class 4-5
• Rheumatoid arthritis or Diabetes mellitus with neuropathy
• Liver or kidney failure
• BMI above 40
• Severe COPD