Postoperative pain following total knee arthroplasty (TKA) is a significant clinical problem that delays early mobilization, reduces patient satisfaction, and increases analgesic requirements. The adductor canal block (ACB), which aims to provide analgesia while preserving motor function, is widely used in postoperative pain management after TKA. However, clinical and anatomical studies have demonstrated that ACB is effective only in the anteromedial sensory innervation of the knee and does not adequately block pain originating from the posterior knee capsule. This limitation reduces analgesic effectiveness, particularly in patients with a prominent posterior pain component.
The sciatic nerve block has long been considered the gold standard for managing posterior knee pain. However, due to disadvantages such as motor weakness and delayed rehabilitation, current pain management protocols increasingly favor motor-sparing and complementary approaches such as the Biceps Femoris Short Head (BiFeS) block and the Interspace Between the Popliteal Artery and the Capsule of the posterior Knee (IPACK) block for posterior knee analgesia.
In light of this information, the aim of our study is to guide clinical practice by comparing the postoperative analgesic efficacy, motor function outcomes, and patient satisfaction associated with sciatic nerve, BiFeS, and IPACK block techniques-each administered as a supplement to the adductor canal block-in patients undergoing total knee arthroplasty, with the ultimate goal of determining the optimal block combination for postoperative pain control.
Patients classified as American Society of Anesthesiologists (ASA) physical status I-III
Patients undergoing primary total knee arthroplasty
Patients undergoing unilateral total knee arthroplasty
Patients between 18 and 75 years of age
Patients classified as American Society of Anesthesiologists (ASA) physical status IV or higher
Patients undergoing revision total knee arthroplasty
Patients undergoing bilateral total knee arthroplasty
Patients with neuromuscular disease
Parallel
Adductor canal block
Procedure/SurgeryAdductor Canal Block An ultrasound-guided injection of 20 mL local anesthetic solution (10 mL 0.25% bupivacaine + 10 mL 0.9% saline) administered in the mid-portion of the adductor canal to provide motor-sparing analgesia to the anteromedial knee.
BiFeS Block (Biceps Femoris Short Head Block)
Procedure/SurgeryBiFeS Block (Biceps Femoris Short Head Block) An ultrasound-guided injection targeting the short head of the biceps femoris muscle to selectively block sensory branches contributing to posterior knee pain. A total of 20 mL of local anesthetic (10 mL 0.25% bupivacaine + 10 mL 0.9% saline) is administered.
IPACK block
Procedure/SurgeryIPACK Block An ultrasound-guided IPACK (Interspace Between the Popliteal Artery and the Capsule of the Posterior Knee) block using 20 mL of local anesthetic solution (10 mL 0.25% bupivacaine + 10 mL 0.9% saline) to provide posterior knee capsular analgesia while sparing motor function.
Sciatic Nerve Block
Procedure/SurgerySciatic Nerve Block An ultrasound-guided sciatic nerve block performed at the proximal thigh level using 20 mL of local anesthetic solution (10 mL 0.25% bupivacaine + 10 mL 0.9% saline) to provide posterior knee analgesia.
Visual Analog Scale (VAS) Pain Score
Pain intensity will be assessed using the Visual Analog Scale (VAS), a 10-cm horizontal line with endpoints representing the extremes of pain (0 = "no pain," 10 = "worst imaginable pain"). Patients will mark their perceived pain level, and the distance (in cm or mm) from the "no pain" anchor will be recorded as the VAS score. Measurements will be performed at rest. A VAS score below 3 indicates mild pain and adequate analgesia.
Modified Bromage Scale
The Modified Bromage Scale is widely used to objectively assess the degree of motor block following spinal or peripheral nerve blocks. The evaluation will be performed after the resolution of spinal anesthesia and during the postoperative period while the peripheral nerve block remains effective. The scores obtained will be recorded to determine the degree of motor block and its potential effects on early mobilization. Score 0 - The patient can freely move the lower extremity (hip, knee, ankle). Score 1 - The patient can move the knee and ankle but cannot move the hip. Score 2 - The patient can move only the ankle; unable to move the knee and hip. Score 3 - The patient is unable to move the lower extremity at all.
QoR-40 (Quality of Recovery-40) Questionnaire
The QoR-40 is a validated and reliable multidimensional instrument designed to assess postoperative recovery. The questionnaire consists of 40 items, each scored on a 5-point Likert scale: 1: Strongly disagree / very poor 5: Strongly agree / excellent Total scores range from 40 to 200, with higher scores indicating better quality of recovery. The QoR-40 evaluates five subdomains: Physical comfort (12 items) Emotional state (9 items) Physical independence (5 items) Psychological support (7 items) Pain (7 items) All patients will complete the questionnaire at the postoperative 24th hour, after receiving verbal instructions. The resulting scores will be analyzed to compare the effects of each block combination on patient comfort and overall recovery quality.
Postoperative Opioid Requirement
The amount of opioid analgesics required during the postoperative period.
Time to First Opioid Requirement
The time to first opioid requirement will be assessed by recording the time the patient requests or receives their first opioid dose post-operatively.
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