This study evaluates the analgesic efficacy and motor-sparing properties of ultrasound-guided Suprainguinal Fascia Iliaca Block (S-FIB) compared with Adductor Canal Block (ACB) in patients undergoing primary total knee arthroplasty (TKA). The main hypothesis is that ACB better preserves quadriceps muscle strength, allowing earlier functional mobilization, while providing comparable (non-inferior) analgesia to S-FIB.
ASA Physical Status I, II, or III
Scheduled for elective unilateral primary total knee arthroplasty
Able to understand and operate the PCA device
Written informed consent provided
Pre-existing lower-extremity neurological deficit or motor weakness (e.g., severe diabetic neuropathy)
Chronic opioid use (>30 mg oral morphine equivalents/day for >3 months)
Infection at the block site or systemic sepsis
Coagulopathy or bleeding diathesis