SII Levels Following PENG Block in Hip Arthroplasty

Pericapsular Nerve Group Block Mitigates Surgical Stress and Enhances Analgesia in Total Hip Arthroplasty: A Randomized Controlled Trial

This randomized controlled trial evaluates the effect of ultrasound-guided Pericapsular Nerve Group (PENG) block on the Systemic Immune-Inflammation Index (SII) in elderly patients undergoing total hip arthroplasty under spinal anesthesia. SII, calculated as platelet × neutrophil / lymphocyte count, is used as a composite marker of perioperative inflammatory and immune response. The study investigates whether PENG block attenuates the systemic inflammatory reaction to surgical trauma compared to sham block.

Study Overview

• Status: Not yet recruiting
• Conditions: Hip Osteoarthritis
• Intervention / Treatment: Drug: Ropivacaine 0.2% Injectable Solution; Drug: sodium Chloride

Detailed Description

Surgical trauma induces a systemic inflammatory response characterized by neutrophilia, lymphopenia, and platelet activation. These hematologic alterations reflect the interaction between innate immune activation, stress-induced immunosuppression, and pro-thrombotic mechanisms. The modulation of this response may influence postoperative recovery and complication risk.

The Systemic Immune-Inflammation Index (SII) is calculated using the formula:

SII = (Platelet count × Neutrophil count) / Lymphocyte count SII integrates three components of systemic inflammation and immune regulation and is considered a more comprehensive marker than isolated ratios such as neutrophil-to-lymphocyte ratio (NLR) or platelet-to-lymphocyte ratio (PLR). Compared with NLR and PLR, SII may better reflect the balance between inflammatory activation and adaptive immune suppression in the perioperative period.

Regional anesthesia techniques, including the Pericapsular Nerve Group (PENG) block, may attenuate surgical stress by reducing afferent nociceptive signaling, sympathetic activation, and subsequent inflammatory cascade activation. While previous studies have evaluated the impact of regional anesthesia on NLR and PLR, the influence of PENG block on SII in hip arthroplasty has not been previously investigated.

The primary objective of this study is to determine whether PENG block reduces postoperative SII levels compared with sham block in elderly patients undergoing total hip arthroplasty under spinal anesthesia.

Peripheral venous blood samples will be collected preoperatively and at predefined postoperative time points (e.g., 12, 24, and 48 hours). The primary endpoint will be postoperative SII at 24 hours or the change from baseline (ΔSII), depending on statistical analysis plan.

This study aims to determine whether motor-sparing regional anesthesia may modulate systemic inflammatory response beyond analgesic effects, potentially contributing to improved perioperative outcomes.

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Patients with ASA classification I-III
• Aged 65-100 years
• Who will be scheduled for hip arthroplasty under spinal anesthesia

Exclusion Criteria:

• Patients who have a history of bleeding diathesis
• Take anticoagulant therapy
• History of chronic pain before surgery
• Multiple trauma
• patients unable to assess their pain (dementia)
• patients operated under general anesthesia
• patients having an infection in the region of the procedure
• the patient who does not accept the procedure

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: PENG block; PENG block with 20ml 0f 0.2% ropivacaine	Drug: Ropivacaine 0.2% Injectable Solution; After spinal anesthesia, the ultrasound-guided PENG block will be performed with 20 ml of 0.2% ropivacaine; Other Names: 0.2% ropivacaine
Sham Comparator: Sham blocks; PENG block with 20ml of 0.9% sodium chloride	Drug: sodium Chloride; After spinal anesthesia, the ultrasound-guided PENG block will be performed with 20ml of 0.9% sodium chloride; Other Names: 0.9% Sodium Chloride Injection

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Systemic Inflammation Response Index (SIRI)	Systemic Inflammation Response Index (SIRI) is used as a composite marker of systemic inflammatory activation. It is calculated from peripheral venous blood samples using the formula: SIRI = (Neutrophil count × Monocyte count) / Lymphocyte count All parameters are obtained from routine complete blood count (CBC) analysis and expressed in ×10⁹/L. SIRI reflects the interaction between innate immune activation (neutrophils and monocytes) and adaptive immune suppression (lymphocytes). Higher SIRI values indicate greater systemic inflammatory response.	12 hours after surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Systemic Inflammation Response Index (SIRI)	Systemic Inflammation Response Index (SIRI) is used as a composite marker of systemic inflammatory activation. It is calculated from peripheral venous blood samples using the formula: SIRI = (Neutrophil count × Monocyte count) / Lymphocyte count All parameters are obtained from routine complete blood count (CBC) analysis and expressed in ×10⁹/L. SIRI reflects the interaction between innate immune activation (neutrophils and monocytes) and adaptive immune suppression (lymphocytes). Higher SIRI values indicate greater systemic inflammatory response.	24 hours after surgery
Systemic Inflammation Response Index (SIRI)	Systemic Inflammation Response Index (SIRI) is used as a composite marker of systemic inflammatory activation. It is calculated from peripheral venous blood samples using the formula: SIRI = (Neutrophil count × Monocyte count) / Lymphocyte count All parameters are obtained from routine complete blood count (CBC) analysis and expressed in ×10⁹/L. SIRI reflects the interaction between innate immune activation (neutrophils and monocytes) and adaptive immune suppression (lymphocytes). Higher SIRI values indicate greater systemic inflammatory response.	48 hours after surgery
Aggregate Index of Systemic Inflammation (AISI)	Aggregate Index of Systemic Inflammation (AISI) is calculated as: AISI = (Neutrophil count × Monocyte count × Platelet count) / Lymphocyte count All values are obtained from routine CBC and expressed in ×10⁹/L. AISI integrates neutrophils, monocytes, platelets, and lymphocytes, providing a broader assessment of systemic inflammatory and immune response compared to single ratios.	12 hours after surgery
Aggregate Index of Systemic Inflammation (AISI)	Aggregate Index of Systemic Inflammation (AISI) is calculated as: AISI = (Neutrophil count × Monocyte count × Platelet count) / Lymphocyte count All values are obtained from routine CBC and expressed in ×10⁹/L. AISI integrates neutrophils, monocytes, platelets, and lymphocytes, providing a broader assessment of systemic inflammatory and immune response compared to single ratios.	24 hours after surgery
Aggregate Index of Systemic Inflammation (AISI)	Aggregate Index of Systemic Inflammation (AISI) is calculated as: AISI = (Neutrophil count × Monocyte count × Platelet count) / Lymphocyte count All values are obtained from routine CBC and expressed in ×10⁹/L. AISI integrates neutrophils, monocytes, platelets, and lymphocytes, providing a broader assessment of systemic inflammatory and immune response compared to single ratios.	48 hours after surgery
Platelet Mass Index (PMI)	Platelet Mass Index (PMI) reflects total circulating platelet mass and is calculated as: PMI = Platelet count × Mean Platelet Volume (MPV) Platelet count is expressed in ×10⁹/L and MPV in femtoliters (fL). PMI reflects platelet activation and thrombo-inflammatory potential, which may increase in response to surgical stress.	12 hours after surgery
Platelet Mass Index (PMI)	Platelet Mass Index (PMI) reflects total circulating platelet mass and is calculated as: PMI = Platelet count × Mean Platelet Volume (MPV) Platelet count is expressed in ×10⁹/L and MPV in femtoliters (fL). PMI reflects platelet activation and thrombo-inflammatory potential, which may increase in response to surgical stress.	24 hours after surgery
Platelet Mass Index (PMI)	Platelet Mass Index (PMI) reflects total circulating platelet mass and is calculated as: PMI = Platelet count × Mean Platelet Volume (MPV) Platelet count is expressed in ×10⁹/L and MPV in femtoliters (fL). PMI reflects platelet activation and thrombo-inflammatory potential, which may increase in response to surgical stress.	48 hours after surgery
C-reactive Protein (CRP) Concentration	C-reactive protein (CRP) is a laboratory marker of acute systemic inflammation measured in peripheral venous blood samples. CRP concentration is expressed in mg/L and determined using standard hospital laboratory methods. Higher CRP values indicate greater postoperative inflammatory response.	12 hours after surgery
C-reactive Protein (CRP) Concentration	C-reactive protein (CRP) is a laboratory marker of acute systemic inflammation measured in peripheral venous blood samples. CRP concentration is expressed in mg/L and determined using standard hospital laboratory methods. Higher CRP values indicate greater postoperative inflammatory response.	24 hours after surgery
C-reactive Protein (CRP) Concentration	C-reactive protein (CRP) is a laboratory marker of acute systemic inflammation measured in peripheral venous blood samples. CRP concentration is expressed in mg/L and determined using standard hospital laboratory methods. Higher CRP values indicate greater postoperative inflammatory response.	48 hours after surgery
Postoperative Pain Intensity (NRS)	Postoperative pain intensity will be assessed using the Numerical Rating Scale (NRS), ranging from 0 to 10, where: 0 = no pain 10 = worst pain imaginable Pain scores will be recorded at rest.	4 hours after surgery
Postoperative Pain Intensity (NRS)	Postoperative pain intensity will be assessed using the Numerical Rating Scale (NRS), ranging from 0 to 10, where: 0 = no pain 10 = worst pain imaginable Pain scores will be recorded at rest.	8 hours after surgery
Postoperative Pain Intensity (NRS)	Postoperative pain intensity will be assessed using the Numerical Rating Scale (NRS), ranging from 0 to 10, where: 0 = no pain 10 = worst pain imaginable Pain scores will be recorded at rest.	12 hours after surgery
Postoperative Pain Intensity (NRS)	Postoperative pain intensity will be assessed using the Numerical Rating Scale (NRS), ranging from 0 to 10, where: 0 = no pain 10 = worst pain imaginable Pain scores will be recorded at rest.	24 hours after surgery
Postoperative Pain Intensity (NRS)	Postoperative pain intensity will be assessed using the Numerical Rating Scale (NRS), ranging from 0 to 10, where: 0 = no pain 10 = worst pain imaginable Pain scores will be recorded at rest.	48 hours after surgery
Opioid Consumption	Total opioid consumption within the first 48 hours after surgery will be recorded. All administered opioids will be converted to intravenous morphine milligram equivalents (MME) for standardization. Higher cumulative MME indicates greater analgesic requirement.	48 hours after surgery
Time to First Rescue Analgesia	Time from completion of surgery to first administration of rescue opioid analgesia. Measured in minutes. Shorter time indicates earlier breakthrough pain.	48 hours after surgery

Collaborators and Investigators

• Sponsor: Poznan University of Medical Sciences

Study record dates

Study Major Dates

• Study Start (Estimated): April 1, 2026
• Primary Completion (Estimated): May 1, 2026
• Study Completion (Estimated): June 30, 2026

Study Registration Dates

• First Submitted: February 27, 2026
• First Submitted That Met QC Criteria: February 27, 2026
• First Posted (Actual): March 4, 2026

Study Record Updates

• Last Update Posted (Actual): March 4, 2026
• Last Update Submitted That Met QC Criteria: February 27, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Arthritis; Joint Diseases; Rheumatic Diseases; Osteoarthritis; Osteoarthritis, Hip; Organic Chemicals; Anilides; Amides; Aniline Compounds; Amines; Inorganic Chemicals; Chlorine Compounds; Sodium Compounds; Chlorides; Hydrochloric Acid; Ropivacaine; Sodium Chloride
• Other Study ID Numbers: 80/26

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES

IPD Plan Description

De-identified individual participant data (IPD) underlying the results reported in publications (including demographic data, laboratory inflammatory indices such as SII, SIRI, AISI, CRP values, pain scores, opioid consumption, and time-to-event outcomes) will be made available to qualified researchers.

Data will be shared after removal of all direct identifiers in accordance with GDPR regulations and institutional data protection policies.

The study protocol, statistical analysis plan (SAP), and analytic code will also be available upon reasonable request.

Data will be provided for the purpose of secondary analyses, meta-analyses, or validation studies, subject to approval by the principal investigator and institutional review board, where applicable.

• IPD Sharing Time Frame: Data will become available 6 months after publication of the primary results and will remain available for 5 years.

IPD Sharing Access Criteria

Access will be granted to researchers who provide:

A methodologically sound research proposal Institutional affiliation Ethical approval (if required) A signed data use agreement Requests should be directed to the principal investigator via institutional email.

• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ANALYTIC_CODE

Drug and device information, study documents

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