iPACK Block vs. Periarticular Infiltration for TKA Pain Control

NCT ID: NCT07267650

Last Updated: 2025-12-05

Basic Information

• Recruitment Status: NOT_YET_RECRUITING
• Clinical Phase: NA
• Total Enrollment: 100 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2026-01-01
• Study Completion Date: 2026-08-01

Brief Summary

This study aims to compare two different multimodal analgesic techniques for pain management after total knee arthroplasty (TKA). The primary purpose is to determine if a combination of two specific nerve blocks administered by an anesthesiologist (Femoral Triangle Block + iPACK block) results in superior pain control compared to a combination of a nerve block and a local infiltration administered by the surgeon (FTB + Periarticular Infiltration [PAI]).

The hypothesis is that the FTB + iPACK combination will lead to a significant reduction in Numeric Rating Scale (NRS) pain scores with movement at 24 hours postoperatively.

This will be a prospective, randomized, double-blind, parallel-group, single-center study involving patients scheduled for primary unilateral TKA. Participants will be randomly assigned to one of two groups. All patients, clinicians (anesthesiologists and surgeon), and outcome assessors will be blinded to the group allocation using a double-dummy technique.

Detailed Description

Total knee arthroplasty (TKA) is a highly successful procedure for end-stage knee osteoarthritis but is associated with significant postoperative pain. Effective pain management is crucial for facilitating early rehabilitation and improving patient comfort. Modern pain management relies on multimodal, opioid-sparing protocols that often include motor-sparing regional anesthesia techniques like the femoral triangle block (FTB).

While FTB provides excellent analgesia for the anterior part of the knee, pain originating from the posterior knee capsule remains a significant challenge. This posterior pain is commonly managed either by the surgeon through a diffuse periarticular infiltration (PAI) of a local anesthetic cocktail or by the anesthesiologist through a targeted, ultrasound-guided block of the posterior capsule known as the iPACK block.

It is currently unclear whether a fully anesthesiologist-driven, neuroanatomically targeted approach (FTB + iPACK) offers superior outcomes compared to a hybrid approach involving both the anesthesiologist and the surgeon (FTB + PAI).

This prospective, randomized, double-blind controlled trial is designed to compare these two advanced analgesic combinations. All patients will receive a standardized spinal anesthetic (3 mL of 0.5% heavy bupivacaine). The study will evaluate which method provides better pain control, measured primarily by Numeric Rating Scale (NRS) pain scores at 24 hours, and secondarily by total rescue analgesic (tramadol) consumption, functional recovery (Timed Up and Go test and Straight Leg Raise test), and knee range of motion.

Sample size will be determined based on an internal pilot study. An initial 30 patients (15 per group) will be enrolled. The mean and standard deviation of the primary outcome (NRS pain score with movement at 24 hours) from this pilot cohort will be used to calculate the final sample size required to detect a clinically significant difference (e.g., 1 point on the NRS) with 80% power and an alpha of 0.05. The final enrollment target is estimated to be approximately 100 patients (50 per group) to account for potential dropouts.

Conditions

Pain, Postoperative; Osteoarthritis, Knee / Osteoarthritis, Hip

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: QUADRUPLE

Study Groups

FTB + iPACK Group (n=50)

Group Type: ACTIVE_COMPARATOR

FTB

Intervention Type: PROCEDURE

All patients will receive an ultrasound-guided Femoral Triangle Block (FTB) with 20 mL of 0.25% Bupivacaine, supplemented by an Anterior Femoral Cutaneous Nerve block with 5 mL of the same solution.

IPACK block

Intervention Type: PROCEDURE

Patients will receive an ultrasound-guided real iPACK block with 20 mL of 0.25% Bupivacaine

Sham Intervention 1 (Surgeon)

Intervention Type: PROCEDURE

Patients will receive a sham Periarticular Infiltration (PAI) with an equivalent volume of normal saline intraoperatively.

Bupivacaine %0.25 (isobaric)

Intervention Type: DRUG

Used for FTB and iPACK blocks.

Normal Saline (0.9% NaCl)

Intervention Type: DRUG

Used for sham/placebo infiltration or block.

FTB + PAI Group (n=50)

Group Type: EXPERIMENTAL

FTB

Intervention Type: PROCEDURE

All patients will receive an ultrasound-guided Femoral Triangle Block (FTB) with 20 mL of 0.25% Bupivacaine, supplemented by an Anterior Femoral Cutaneous Nerve block with 5 mL of the same solution.

Sham Intervention 2 (Anesthesiologist)

Intervention Type: PROCEDURE

Patients will receive a sham iPACK block with an equivalent volume of normal saline preoperatively.

PAI (Surgeon)

Intervention Type: PROCEDURE

The surgeon intraoperatively administers the standardized PAI cocktail (total volume approx. 50 mL): 24 mL 0.5% Bupivacaine, 0.3 mL Adrenaline (1:1000), 40 mg Methylprednisolone, 1 gr Cefazoline, and 22 mL 0.9% Sodium Chloride. The surgeon will administer the infiltration into the medial, lateral, and posterior quadrants of the knee capsule, specifically sparing the anterior quadrant.

Bupivacaine %0.25 (isobaric)

Intervention Type: DRUG

Used for FTB and iPACK blocks.

Bupivacaine + Adrenaline + Methylprednisolone + Cefazoline

Intervention Type: DRUG

Used for PAI

Normal Saline (0.9% NaCl)

Intervention Type: DRUG

Used for sham/placebo infiltration or block.

Interventions

FTB

All patients will receive an ultrasound-guided Femoral Triangle Block (FTB) with 20 mL of 0.25% Bupivacaine, supplemented by an Anterior Femoral Cutaneous Nerve block with 5 mL of the same solution.

Intervention Type: PROCEDURE

IPACK block

Patients will receive an ultrasound-guided real iPACK block with 20 mL of 0.25% Bupivacaine

Intervention Type: PROCEDURE

Sham Intervention 1 (Surgeon)

Patients will receive a sham Periarticular Infiltration (PAI) with an equivalent volume of normal saline intraoperatively.

Intervention Type: PROCEDURE

Sham Intervention 2 (Anesthesiologist)

Patients will receive a sham iPACK block with an equivalent volume of normal saline preoperatively.

Intervention Type: PROCEDURE

PAI (Surgeon)

The surgeon intraoperatively administers the standardized PAI cocktail (total volume approx. 50 mL): 24 mL 0.5% Bupivacaine, 0.3 mL Adrenaline (1:1000), 40 mg Methylprednisolone, 1 gr Cefazoline, and 22 mL 0.9% Sodium Chloride. The surgeon will administer the infiltration into the medial, lateral, and posterior quadrants of the knee capsule, specifically sparing the anterior quadrant.

Intervention Type: PROCEDURE

Bupivacaine %0.25 (isobaric)

Used for FTB and iPACK blocks.

Intervention Type: DRUG

Bupivacaine + Adrenaline + Methylprednisolone + Cefazoline

Used for PAI

Intervention Type: DRUG

Normal Saline (0.9% NaCl)

Used for sham/placebo infiltration or block.

Intervention Type: DRUG

Eligibility Criteria

Inclusion Criteria

• American Society of Anesthesiologists (ASA) physical status II-III.
• Scheduled for elective, primary, unilateral total knee arthroplasty for osteoarthritis.
• Able to provide written informed consent.

Exclusion Criteria

• Patient refusal to participate or contraindication to regional anesthesia.
• Known allergy to any study medications (local anesthetics, NSAIDs, tramadol, morphine, paracetamol).
• History of chronic opioid use (defined as daily use for >3 months)
• Pre-existing peripheral neuropathy in the operative limb.
• Severe renal or hepatic insufficiency.
• Cognitive impairment preventing the use of pain scales or questionnaires.
• Revision or bilateral knee arthroplasty.

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 80 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Turgutlu State Hospital

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Aslan

Role: PRINCIPAL_INVESTIGATOR

Turgutlu State Hospital

Central Contacts

Celil M Aslan, Medical Doctor

Role: CONTACT

mcaslan@outlook.com.tr

+90505534900

Other Identifiers

ANES-TKA-2025-001

Identifier Type: -

Identifier Source: org_study_id