Effect of iPACK and BiFeS Blocks on Quality of Recovery After Total Knee Arthroplasty

Summary

This prospective, randomized, double-blind clinical trial aims to compare the effects of two different posterior knee analgesia techniques-iPACK block (Interspace Between the Popliteal Artery and the Capsule of the posterior Knee) and the Biceps Femoris Short Head (BiFeS) block-when combined with an adductor canal block (ACB) in patients undergoing elective unilateral total knee arthroplasty (TKA). Effective postoperative analgesia is essential for early mobilization, enhanced recovery, and patient satisfaction after TKA. Although ACB provides good anterior knee analgesia while preserving quadriceps strength, additional posterior knee analgesia is often required.

The iPACK block is a commonly used technique that targets the posterior knee capsule, whereas the newer BiFeS block aims to provide more selective posterolateral sensory blockade with potentially reduced risk of motor involvement. However, comparative clinical data between these two techniques are limited.

The primary objective of this study is to evaluate the difference between the iPACK and BiFeS blocks in terms of Quality of Recovery-15 (QoR-15) scores at 24 hours postoperatively. Secondary objectives include comparisons of postoperative pain scores, opioid consumption, time to first analgesic request, quadriceps and anterior tibialis muscle strength, functional test performance, time to mobilization, active range of motion, and the incidence of adverse events.

A total of 74 adult patients scheduled for elective unilateral TKA under spinal anesthesia will be randomized in a 1:1 ratio into two groups: ACB + iPACK block or ACB + BiFeS block. All blocks will be performed under ultrasound guidance by an experienced anesthesiologist. Outcome assessments will be conducted by blinded investigators. The study aims to provide high-quality clinical evidence regarding the effectiveness of the BiFeS block compared to the widely used iPACK technique.

Conditions

• Knee Osteoarthritis
• Postoperative Pain Management
• Total Knee Arthroplasty

Interventions

PROCEDURE

Adductor Canal Block (ACB) Only

An ultrasound-guided adductor canal block (ACB) will be performed using 15 mL of 0.25% bupivacaine. The probe will be placed on the proximal thigh to visualize the sartorius muscle and femoral artery. The needle will be advanced in-plane into the adductor canal, and correct placement will be confirmed with 2 mL saline before injection. This block aims to provide anterior knee analgesia while preserving quadriceps strength.

PROCEDURE

IPACK block

The iPACK block will be performed by placing the ultrasound probe at the popliteal region to visualize the popliteal artery and posterior knee capsule. A needle will be advanced in-plane, and 25 mL of 0.25% bupivacaine will be injected between the artery and posterior capsule. This block targets posterior knee pain after total knee arthroplasty without causing motor block.

PROCEDURE

BiFeS Block

The BiFeS block will be performed with the ultrasound probe placed laterally to visualize the femur cortex and the long and short heads of the biceps femoris muscle. The needle will be advanced in-plane into the potential space between the femur and the short head of the biceps femoris. After confirming position with 2 mL saline, 25 mL of 0.25% bupivacaine will be injected. This block provides posterolateral knee analgesia with limited motor involvement.

Sponsors & Collaborators

• Ataturk University

  lead OTHER

Principal Investigators

• Ahmet Murat Yayık, Principal Investigator · Ataturk University Department of Anesthesiology and Reanimation

• Mehmet Akif YILMAZ, assistant doctor · Ataturk University Department of Anesthesiology and Reanimation

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

75 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2025-12-01

Primary Completion

2026-07-01

Completion

2026-07-02

Countries

• Turkey (Türkiye)

Study Locations