Supplementary Nerve Blocks Added to the Adductor Canal Block for Postoperative Pain Management in Primary Total Knee Arthroplasty: A Randomized Controlled Comparison of Sciatic, BiFeS, and IPACK Techniques

Condition(s) studied

Investigational drug(s) / intervention(s)

Adductor canal block: Adductor 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): BiFeS 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: IPACK 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: Sciatic 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.

Study summary

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.

Eligibility

Primary outcome measure(s)

• Visual Analog Scale (VAS) Pain Score — Postoperative 24 hours (measured at 1, 4, 8, 12, and 24 hours)
  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.

Trial sites (1)

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