Comparison of the Postoperative Analgesic Efficacy of Infiltration Between the Popliteal Artery and the Capsule of the Knee (iPACK) Block and the Biceps Femoris Short Head Plane (BiFeS) Block in Total Knee Arthroplasty

Comparison of the Postoperative Analgesic Efficacy of Infiltration Between the Popliteal Artery and the Capsule of the Knee (iPACK) Block and the Biceps Femoris Short Head Plane (BiFeS) Block in Total Knee Arthroplasty: A Prospective, Randomized, Double-Blind, Non-Inferiority Trial

This study aims to compare the effects of two regional analgesia techniques applied in patients undergoing unilateral total knee arthroplasty-Infiltration between the Popliteal Artery and the Capsule of the Knee (iPACK) block and the Biceps Femoris Short Head Plane (BiFeS) block-on ease of application, postoperative pain scores, time to mobilization, total postoperative opioid consumption, need for first rescue analgesia, and the incidence of nausea-vomiting and pruritus.All patients will be followed postoperatively according to a standard pain management protocol, and pain assessments will be performed at predetermined time intervals using the VAS (Visual Analog Scale).

Study Overview

• Status: Not yet recruiting
• Conditions: Postoperative Pain
• Intervention / Treatment: Procedure: IPACK block; Procedure: BiFeS Block

Detailed Description

Total knee arthroplasty is one of the most commonly performed orthopedic procedures. Patients experience significant pain in the postoperative period. This pain delays recovery, prolongs the time to mobilization, and increases the length of hospital stay. Currently, multimodal analgesia techniques are used for postoperative pain management. These methods include systemic opioids, epidural analgesia, lumbar plexus block, femoral block, adductor canal block, iPACK block, and the newly defined and proven effective BiFeS block.

In recent years, the adductor canal block has been frequently preferred because it is applied more distally and does not cause motor blockade. It primarily provides analgesia to the anteromedial aspect of the knee.

The iPACK block and the BiFeS block can be used as complementary techniques to the adductor canal block, as they also affect the nerves responsible for the posterolateral innervation of the knee. Since they do not produce motor blockade, they are thought to contribute to early postoperative mobilization. During the iPACK block, local anesthetic is infiltrated between the posterior capsule of the knee and the popliteal artery. It has also been shown that a superior lateral genicular nerve block should be added to this block. The BiFeS block is performed with the patient in the supine position by infiltrating local anesthetic between the short head of the biceps femoris muscle and the lateral femoral condyle at a more proximal level. Due to its distance from the surgical site, the risk of infection is lower.

In this study, the investigators aimed to compare the ease of application and the roles of these blocks-routinely performed at our center as part of multimodal analgesia-in providing effective postoperative analgesia.

• Study Type: Interventional
• Enrollment (Estimated): 100
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Meltem Savas Ozdemir, MD; Phone Number: +905557331143; Email: drmeltemsavas@gmail.com

Study Locations

• Turkey (Türkiye)
  • Soma
    • Manisa, Soma, Turkey (Türkiye), 45500
      • Soma State Hospital
      • Contact: Meltem Savas Ozdemir, MD; Phone Number: +905557331143; Email: drmeltemsavas@gmail.com
      • Sub-Investigator: Pelin Dilsiz Eker, MD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patients scheduled for unilateral total knee arthroplasty
• Patients aged between 18 and 75 years
• Patients with ASA physical status I-III

Exclusion Criteria:

• Patients with neuropsychiatric disorders
• Patients with obesity (BMI > 30)
• Presence of local infection at the site where the block will be performed
• Patients with coagulation disorders
• Patients with uncontrolled diabetes mellitus
• Opioid dependence
• History of allergy to local anesthetic agents
• Refusal to participate in the study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: iPACK Block; At the end of surgery, all patients will receive an adductor canal block in the recovery unit under sterile conditions and ultrasound guidance using 10 mL of 0.25% bupivacaine. In addition, in the iPACK block group, the patient will be positioned in the lateral decubitus position, and under sterile conditions, a linear ultrasound probe will be used to advance a 22G, 100-mm block needle to the space between the popliteal artery and the posterior capsule of the knee. After negative aspiration, an iPACK block will be performed with 25 mL of 0.25% bupivacaine.	Procedure: IPACK block; Unilateral iPACK block with 25 mL of mixture 1:1 (0.5 % bupivacaine: 0.9% NaCl)
Other: BiFeS Block; At the end of surgery, all patients will receive an adductor canal block in the recovery unit under sterile conditions and ultrasound guidance using 10 mL of 0.25% bupivacaine. In addition, in the BiFeS block group, with the patient in the supine position and under sterile conditions, a linear ultrasound probe will be used, and a 22G, 100-mm block needle will be advanced to the space between the short head of the biceps femoris muscle and the lateral epicondyle of the femur. After negative aspiration, the BiFeS block will be performed using 25 mL of 0.25% bupivacaine.	Procedure: BiFeS Block; Unilateral BiFeS block with 25 mL of mixture 1:1 (0.5 % bupivacaine: 0.9% NaCl)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
VAS Scores	A score of 0 indicates no pain, while a score of 10 represents the worst pain imaginable.	Postoperative 8th-hour

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
VAS Scores	A score of 0 indicates no pain, while a score of 10 represents the worst pain imaginable.	Postoperative 2,4,6,12,24th-hour rest and movement
Total opioid consumption	Patients with a VAS score > 4 will receive 1 mg/kg intravenous tramadol.	24 hours after surgery
Time to first mobilization	The postoperative hour at which the patients are comfortably mobilized is recorded.	24 hours after surgery

Collaborators and Investigators

• Sponsor: Soma State Hospital

Publications and helpful links

General Publications

• Kilicaslan A, Tulgar S, Ahiskalioglu A, Aycan IO, Kekec AF, Arici AG, Kilic G, Sindel M. Ultrasound-guided biceps femoris short head block: a novel regional anesthesia technique for the posterolateral knee. Pain Med. 2025 Nov 1;26(11):726-732. doi: 10.1093/pm/pnaf068.
• Sarikaya Ozel E, Taflan MG. Ultrasound-Guided Biceps Femoris Short Head Block for Posterolateral Knee Analgesia After Total Knee Arthroplasty: A Case Report. A A Pract. 2025 Sep 23;19(9):e02060. doi: 10.1213/XAA.0000000000002060. eCollection 2025 Sep 1.
• Akesen S, Akesen B, Atici T, Gurbet A, Ermutlu C, Ozyalcin A. Comparison of efficacy between the genicular nerve block and the popliteal artery and the capsule of the posterior knee (IPACK) block for total knee replacement surgery: A prospective randomized controlled study. Acta Orthop Traumatol Turc. 2021 Mar;55(2):134-140. doi: 10.5152/j.aott.2021.20187.

Helpful Links

• Ultrasound-guided biceps femoris short head block: a novel regional anesthesia technique for the posterolateral knee
• Comparison of efficacy between the genicular nerve block and the popliteal artery and the capsule of the posterior knee (IPACK) block for total knee replacement surgery: A prospective randomized controlled study
• Ultrasound-Guided Biceps Femoris Short Head Block for Posterolateral Knee Analgesia After Total Knee Arthroplasty: A Case Report

Study record dates

Study Major Dates

• Study Start (Estimated): May 15, 2026
• Primary Completion (Estimated): September 15, 2026
• Study Completion (Estimated): September 16, 2026

Study Registration Dates

• First Submitted: February 19, 2026
• First Submitted That Met QC Criteria: February 19, 2026
• First Posted (Actual): February 25, 2026

Study Record Updates

• Last Update Posted (Actual): May 4, 2026
• Last Update Submitted That Met QC Criteria: April 28, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: iPACK Block; BiFeS Block; Postoperative pain scores; Time to mobilization; Total opioid consumption
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Postoperative Complications; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Pain, Postoperative
• Other Study ID Numbers: BiFeS2026

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No