Effect of a Sciatic Block (SNB) Combined With a Continuous Femoral Block (CFNB) on Pain Scores After Knee Arthroplasty

Centro Hospitalar do Porto

Status: Completed

Conditions: Postoperative Pain

Treatments: Procedure: CFNB; Procedure: SNB plus CFNB

Study type: Interventional

Funder types: Other

Identifiers

NCT01337115

TA 007/11(004-DEFI/007-CES)

Details and patient eligibility

About

The purpose of this study is to determine if the addition of a sciatic nerve block (SNB) to a continuous femoral nerve block (CFNB) improves post-operative analgesia after knee arthroplasty.

Full description

Background: Postoperative pain after total knee replacement /arthroplasty (TKA) is a major concern. It is severe pain in 60% of patients and moderate in 30%. Continuous femoral nerve blocks (CFNB) are considered an excellent choice for regional anesthesia for major knee repair but there are some controversies about the need of supplemental obturator or sciatic nerve blocks for achieving better postoperative analgesia. A recent meta-analysis states there is no sufficient evidence to recommend or discharge these associations.

Objectives: We aim to assess the efficacy of the association of a sciatic nerve block (SNB) and a continuous femoral nerve block (CFNB) for reducing postoperative pain in patients submitted to TKA. Methods: A randomized controlled study on 50 patients submitted to TKA. Control group receives a femoral nerve block with a catheter before general anesthesia is induced and the intervention group gets a similar block plus a single shot SNB before general anesthesia. Both groups start a continuous local anesthetic infusion through femoral catheter after the end of surgery and supplemental oral diclofenac and paracetamol. Pain scores are measured until 24h postoperatively, side effects and patient satisfaction are monitored.

Enrollment: 50 patients

Sex: All

Volunteers: No Healthy Volunteers

Inclusion criteria

• Unilateral total knee replacement

Exclusion criteria

• Contra-indication for general anesthesia
• Infection on puncture site
• Coagulation disorders
• Pre-existent neuropathies
• Allergies to local anesthetics, paracetamol, diclofenac and tramadol
• Severe dyspepsia
• Less than 50kg weigh
• Body Mass Index (BMI) greater than 40
• American Society of Anesthesiologists (ASA) Physical Status 4 or 5
• Absence of capacity to use the Visual Analog Score (VAS) scale
• Refusal to give informed consent

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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50 participants in 2 patient groups

Continuous femoral nerve block (CFNB)

Active Comparator group

Description:

A continuous femoral nerve block is performed for peri-operative analgesia and a bolus of 30 ml of ropivacaine 0.375% is injected before induction of general anesthesia and surgery starts. An infusion of 8ml/h of ropivacaine 0.2% is started in post anesthesia care unit (PACU) and maintained for 48h

Treatment:

Procedure: CFNB

Single shot SNB plus CFNB

Experimental group

Description:

A single shot sciatic nerve block (SNB) is performed before surgery with 25ml of 0.2% ropivacaine in addition to the continuous femoral nerve block (CFNB) performed in the control group before induction of general anesthesia and surgery starts. An infusion of 8ml/h of ropivacaine 0.2% is started in Post anesthesia care unit (PACU) and maintained for 48h

Treatment:

Procedure: SNB plus CFNB