The Efficacy of Peripheral Nerve Blocks With Intrathecal Morphine in Improving Analgesia After Unilateral Total Knee Arthroplasty

Study Overview
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Brief Summary
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The purpose of this study is to determine whether intrathecal morphine (ITM) alone or its combination with peripheral nerve blocks (PNB) provides better analgesia for patients undergoing total knee arthroplasty (TKA).

Detailed Description
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Total knee arthroplasty (TKA) surgery is associated with severe pain. The success of knee rehabilitation following surgery depends largely on adequate pain control that permits early physical therapy. Postoperative modern analgesic recommendations specific to TKA propose either spinal block with intrathecal morphine (ITM) or a combination of general anesthesia with single shot femoral nerve block (SFNB). Femoral nerve block (FNB) too has proven analgesic advantages in TKA surgery. However, we do not know if the combination of the two analgesic techniques, ITM and peripheral nerve blocks (PNB), provides superior analgesia to ITM alone. Thus, this study aims to determine whether ITM alone or its combination with PNB provides better analgesia for patients undergoing total knee arthroplasty (TKA). Eligible patients undergoing unilateral TKA under spinal anesthesia consenting to a multimodal analgesic regimen inclusive of ITM, FNB, and SNB will be recruited. All patients will receive spinal with intrathecal morphine. Patients will be randomly assigned using a computer generated table of random numbers to receive either spinal with intrathecal morphine (morphine group), a combination of intrathecal morphine and femoral nerve block (morphine-femoral group), or a combination of intrathecal morphine and femoral nerve block as well as sciatic nerve block (morphine-femoral-sciatic group).

Official Title
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Do Peripheral Nerve Blocks When Used as Part of a Multimodal Regimen Inclusive on Intrathecal Morphine Improve Analgesia After Unilateral Total Knee Arthroplasty? A Randomized Controlled Trial

Conditions
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Anesthesia, Total Knee Arthroplasty

Intervention / Treatment
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* Drug: Combined spinal epidural anesthesia technique with intrathecal morphine
* Drug: A combination of combined spinal-epidural (with intrathecal morphine) and femoral nerve block
* Drug: A combination of combined spinal-epidural (with intrathecal morphine) and femoral nerve block as well as sciatic nerve block


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ASA I-III patients undergoing unilateral TKA under spinal anesthesia and nerve blocks Ages 18-80 BMI ≤ 38 kg/m2 Exclusion Criteria: BMI > 38 kg/m2 chronic pain disorders Significant pre-existing neurological deficits or peripheral neuropathy affecting the lower extremity abuse of drugs or alcohol Contraindication to a component of multi-modal analgesia Contraindication to spinal anesthesia or failure to institute spinal anesthesia after performing femoral and sciatic blocks Bilateral TKA surgeries History of significant psychiatric conditions that may affect patient assessment Pregnancy Moderate to severe obstructive sleep apnea. Previous adverse reactions resulting from intrathecal opioids (respiratory depression, urinary retention, severe pruritis, severe nausea or vomiting, severe sedation) inability to provide informed consent.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Morphine group<br>Patients will receive a combined spinal epidural anesthesia technique with intrathecal morphine | Drug: Combined spinal epidural anesthesia technique with intrathecal morphine<br> <br> |
| Active Comparator: Morphine-femoral group<br>Patients will receive a combination of combined spinal-epidural (with intrathecal morphine) and femoral nerve block | Drug: A combination of combined spinal-epidural (with intrathecal morphine) and femoral nerve block<br> <br> |
| Active Comparator: Morphine-femoral-sciatic group<br>Patients will receive a combination of combined spinal-epidural (with intrathecal morphine) and femoral nerve block as well as sciatic nerve block | Drug: A combination of combined spinal-epidural (with intrathecal morphine) and femoral nerve block as well as sciatic nerve block<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Postoperative parenteral morphine consumption |  | first 24 hours post-operation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Visual analogue pain scores (VAS) in anterior and posterior knee |  | within 24-48 hours after surgery | 
| Severity of pain in anterior and posterior knee |  | 1 week postoperatively | 
| Time to first IV PCA bolus |  | within first 12 hours | 
| Total IV PCA consumption upon discontinuation of PCA |  | 24-48 hours after surgery | 
| Side effects | Patients will be closely monitored during their hospital stay. Patients will be assessed in their rooms twice daily by a pain nurse, and additionally as required, to report the occurrence of side effects including: block complications, incidence of falls, numbness over femoral distribution, nausea & vomiting, pruritus, occurrence of urinary retention, occurrence of respiratory depression. | within 24 hours after surgery | 
| Patient satisfaction with pain control |  | 24-48 hours after surgery | 
| complications | Patients will be contacted by a member of the research team (by phone) to check for complications including: numbness in the anterior thigh, numbness in the foot, pain and/or bruising around the site where the anesthetic were injected, weakness in thigh muscles, weakness in foot muscles | 1 month after surgery |