iPACK Block vs. Periarticular Infiltration for TKA Pain Control

Turgutlu State Hospital

Status: Not yet enrolling

Conditions: Pain, Postoperative; Osteoarthritis, Knee / Osteoarthritis, Hip

Treatments: Drug: Bupivacaine %0.25 (isobaric); Procedure: FTB; Drug: Normal Saline (0.9% NaCl); Drug: Bupivacaine + Adrenaline + Methylprednisolone + Cefazoline; Procedure: PAI (Surgeon); Procedure: IPACK block; Procedure: Sham Intervention 1 (Surgeon); Procedure: Sham Intervention 2 (Anesthesiologist)

Study type: Interventional

Funder types: Other

Identifiers

NCT07267650

ANES-TKA-2025-001

Details and patient eligibility

About

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.

Full 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.

Enrollment: 100 estimated patients

Sex: All

Ages: 18 to 80 years old

Volunteers: No Healthy Volunteers

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.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Quadruple Blind

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100 participants in 2 patient groups

FTB + iPACK Group (n=50)

Active Comparator group

Treatment:

Procedure: Sham Intervention 1 (Surgeon)

Procedure: IPACK block

Drug: Normal Saline (0.9% NaCl)

Procedure: FTB

Drug: Bupivacaine %0.25 (isobaric)

FTB + PAI Group (n=50)

Experimental group

Treatment:

Procedure: Sham Intervention 2 (Anesthesiologist)

Procedure: PAI (Surgeon)

Drug: Normal Saline (0.9% NaCl)

Drug: Bupivacaine + Adrenaline + Methylprednisolone + Cefazoline

Procedure: FTB

Drug: Bupivacaine %0.25 (isobaric)