Postoperative Pain
Conditions
Keywords
Postoperative pain, Knee arthroplasty, Peripheral nerve blocks, Sciatic nerve block, Femoral nerve block
Brief summary
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.
Detailed 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.
Interventions
PROCEDURESNB plus CFNB
A single shot sciatic nerve block (SNB) is performed with 25 ml of 0.2% ropivacaine before surgery in addition to an isolated continuous femoral nerve block (CFNB) in the control group
PROCEDURECFNB
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
Sponsors
Universidade do Porto
Centro Hospitalar do Porto
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Healthy volunteers
No
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Visual Analogue Scores (VAS) - Pain Scores Measured in mm (0-100) | 15-30 min after arrival on post anesthesia care unit (PACU) | Pain scores measured by Visual Analogue Score (VAS) scale at 15-30min after Post anesthesia care unit (PACU) arrival VAS is a 100mm scale to measure pain. 0mm - no pain 100mm - worst possible pain |
| VAS Results - Pain Measured in mm (0-100) | 12h after surgery | VAS pain scores are measured by blinded investigators 12h after surgery . VAS scale: 0 - no pain 100 - worst possible pain |
| VAS Results - Pain Scores Measured in mm (0-100) | 24h after surgery | VAS pain scores are measured by blinded investigators 24h after surgery . VAS scale: 0 - no pain 100 - worst possible pain |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Satisfaction With Anesthesia Technique in Each Arm of the Study | 1 month after surgery | Satisfaction with the anesthesia technique using a categorical scale with three levels: Bad Reasonable Good/Very Good A Fisher's Exact test is made to asses any differences in the distribution of patients in each arm to each level of the categorical scale |
Countries
Portugal
Participant flow
Recruitment details
April 2011-February 2012. Consecutive patients for total knee arthroplasty at Orthopedic Department, Centro Hospitalar do Porto
Pre-assignment details
Patients were excluded before randomization if refuse, could not use Visual Analogue Scale (VAS) scale, had contraindications for any of the components of the anesthesia protocol or, anesthesiologist was not expert in peripheral blocks
Participants by arm
| Arm | Count |
|---|---|
| Continuous Femoral Nerve Block (CFNB) A continuous femoral nerve block is performed for peri-operative analgesia and a bolus of 30 ml of ropivacaine 0.375% is injected before surgery starts. An infusion of 8ml/h of ropivacaine 0.2% is started in PACU and maintained for 48h | 25 |
| Single Shot Sciatic Nerve Block (SNB) A single shot sciatic nerve block is performed before surgery with 25ml of 0.2% ropivacaine in addition to the continuous femoral nerve block performed in the control group | 25 |
| Total | 50 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Protocol Violation | 2 | 0 |
Baseline characteristics
| Characteristic | Single Shot Sciatic Nerve Block (SNB) | Continuous Femoral Nerve Block (CFNB) | Total |
|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 10 Participants | 15 Participants | 25 Participants |
| Age, Categorical Between 18 and 65 years | 15 Participants | 10 Participants | 25 Participants |
| Age Continuous | 65.44 years STANDARD_DEVIATION 8.93 | 68.16 years STANDARD_DEVIATION 9.83 | 66.8 years STANDARD_DEVIATION 9.4 |
| Region of Enrollment Portugal | 25 participants | 25 participants | 50 participants |
| Sex: Female, Male Female | 16 Participants | 20 Participants | 36 Participants |
| Sex: Female, Male Male | 9 Participants | 5 Participants | 14 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — |
| other Total, other adverse events | 0 / 25 | 0 / 25 |
| serious Total, serious adverse events | 0 / 25 | 0 / 25 |
Outcome results
Primary
VAS Results - Pain Measured in mm (0-100)
VAS pain scores are measured by blinded investigators 12h after surgery . VAS scale: 0 - no pain 100 - worst possible pain
Time frame: 12h after surgery
Population: All 25 patients in each arm completed the protocol. Analysis was made in an ITT manner.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Continuous Femoral Nerve Block (CFNB) | VAS Results - Pain Measured in mm (0-100) | 26.1 units on a scale | Standard Deviation 23.8 |
| Single Shot Sciatic Nerve Block (SNB) | VAS Results - Pain Measured in mm (0-100) | 9.2 units on a scale | Standard Deviation 14.8 |
Comparison: Null hypothesis states that there is no difference between groups. Power 80%p-value: 0.00695% CI: [5.52, 28.33]t-test, 2 sided
Primary
VAS Results - Pain Scores Measured in mm (0-100)
VAS pain scores are measured by blinded investigators 24h after surgery . VAS scale: 0 - no pain 100 - worst possible pain
Time frame: 24h after surgery
Population: In the CFNB group 2 patients did not complete the protocol. Analysis was made in an ITT manner and Last Observational Carried Forward (LOCF) was the imputation technique used. In the SNB group, all 25 patients completed the protocol
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Continuous Femoral Nerve Block (CFNB) | VAS Results - Pain Scores Measured in mm (0-100) | 30.13 units on a scale | Standard Deviation 24.97 |
| Single Shot Sciatic Nerve Block (SNB) | VAS Results - Pain Scores Measured in mm (0-100) | 32.68 units on a scale | Standard Deviation 24.49 |
Comparison: Null hypothesis states there is no difference between both groups. Power 80% to detect 15% difference in meansp-value: 0.72395% CI: [-16.93, 11.83]t-test, 2 sided
Primary
Visual Analogue Scores (VAS) - Pain Scores Measured in mm (0-100)
Pain scores measured by Visual Analogue Score (VAS) scale at 15-30min after Post anesthesia care unit (PACU) arrival VAS is a 100mm scale to measure pain. 0mm - no pain 100mm - worst possible pain
Time frame: 15-30 min after arrival on post anesthesia care unit (PACU)
Population: Participants were analyzed in an Intention to treat (ITT) manner. All randomized subjects (25 in each arm) completed the protocol so all were included for analysis as planned.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Continuous Femoral Nerve Block (CFNB) | Visual Analogue Scores (VAS) - Pain Scores Measured in mm (0-100) | 59.4 units on a scale | Standard Deviation 27.2 |
| Single Shot Sciatic Nerve Block (SNB) | Visual Analogue Scores (VAS) - Pain Scores Measured in mm (0-100) | 30.2 units on a scale | Standard Deviation 30.5 |
Comparison: Difference between mean VAS pain scores. Power 80%. Null hypothesis states there is no difference between pains scores in both groupsp-value: 0.00195% CI: [11.55, 45.34]t-test, 2 sided
Secondary
Satisfaction With Anesthesia Technique in Each Arm of the Study
Satisfaction with the anesthesia technique using a categorical scale with three levels: Bad Reasonable Good/Very Good A Fisher's Exact test is made to asses any differences in the distribution of patients in each arm to each level of the categorical scale
Time frame: 1 month after surgery
Population: Analysis was performed on Participants available for telephone contact one month after surgery and was made per protocol.
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Continuous Femoral Nerve Block (CFNB) | Satisfaction With Anesthesia Technique in Each Arm of the Study | Bad | 0 participants |
| Continuous Femoral Nerve Block (CFNB) | Satisfaction With Anesthesia Technique in Each Arm of the Study | Reasonable | 3 participants |
| Continuous Femoral Nerve Block (CFNB) | Satisfaction With Anesthesia Technique in Each Arm of the Study | Good/Very Good | 17 participants |
| Single Shot Sciatic Nerve Block (SNB) | Satisfaction With Anesthesia Technique in Each Arm of the Study | Bad | 0 participants |
| Single Shot Sciatic Nerve Block (SNB) | Satisfaction With Anesthesia Technique in Each Arm of the Study | Reasonable | 2 participants |
| Single Shot Sciatic Nerve Block (SNB) | Satisfaction With Anesthesia Technique in Each Arm of the Study | Good/Very Good | 11 participants |
p-value: 0.537Fisher's exact test