Mepivacaine vs. Bupivacaine Spinal Anesthetic in Total Knee Arthroplasty

Study Overview
=================
Brief Summary
-----------------
The purpose of this study is to determine if a shorter-acting spinal anesthetic called mepivacaine has advantages over a longer-acting medication called bupivacaine.

Detailed Description
-----------------
Different medications last for different amounts of time and can be changed depending on the length of the procedure. A short acting spinal is generally used for procedures lasting less than 90 minutes. A longer acting medication would be any that lasts longer than 90 minutes. These medications not only block the signals that travel along the pain nerves, they also prevent the signals that tell the patients muscles to move. This means that after a total knee replacement a patient may delayed in their ability to get up and start walking early after surgery. Walking early in the recovery has been shown to decrease the rate of pulmonary embolism and death. Ambulating early is also important to prevent loss of strength, constipation, pneumonia and urinary retention.

Official Title
-----------------
Mepivacaine vs. Bupivacaine Spinal Anesthetic in Total Knee Arthroplasty, a Randomized Controlled Clinical Trial

Conditions
-----------------
Anesthesia, Spinal, Arthroplasty, Replacement, Knee, Pain Management, Early Ambulation, Ambulatory Surgical Procedures

Intervention / Treatment
-----------------
* Drug: Mepivacaine
* Drug: Bupivacaine


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Adult patients undergoing primary total knee arthroplasty Exclusion Criteria: Chronic opioid users Unable to give informed consent Forego the use of a foley catheter Those with hypersensitively to amide local anesthetics or opioids Those with contraindications to spinal anesthesia Conversion to general anesthesia will be excluded.

Ages Eligible for Study
-----------------
Minimum Age: 40 Years
Maximum Age: 90 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Mepivacaine Spinal Anesthetic<br>Mepivacaine 3 mL intrathecal injection of 2% solution | Drug: Mepivacaine<br>* This is a shorter acting spinal anesthetic as compared to the current standard of care at this institution.<br>* Other names: Carbocaine;|
| Active Comparator: Bupivacaine Spinal Anesthetic<br>Bupivacaine 12 mg of 8.25% solution | Drug: Bupivacaine<br>* This is the current standard of care at this institution and many centers. This is a longer acting spinal anesthetic compared to the study drug.<br>* Other names: CAS 38396-39-3;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Return of motor and sensory function | Times will be recorded in minutes from the administration of the spinal anesthetic. Normal exam will include intact sensation to light touch of the thigh, calf, foot and toes. Normal motor is defined as ability to perform a straight leg raise, active knee flexion, as well as wiggling of the ankle and toes. | Exams will take place in 15 minute intervals beginning with arrival to the PACU and will be continued for a maximum of 6 hours or until the exam returns to baseline for 2 consecutive exams. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pain | visual analog scale from 0 - 10 | Entire hospital admission. No data will be recorded after 96 hours. | 
| Pain | morphine equivalent consumption | Hospital admission, maximum of 96 hours. | 
| Time to urination | The total time between the administration of spinal anesthesia to the first episode of spontaneous urination will be recorded. Patients who require greater than 6 hours to urinate independently are followed per hospital protocol with serial bladder scans and straight catheterization for urinary retention as needed. Patients who exceed 6 hours to urinate will be defined as having urinary retention. | 24 hours maximum from time of spinal. | 
| Urinary retention | The number of straight catheterization and foley placements will be recorded as well. | Entire hospital stay beginning immediately in the post operative period until discharge to a maximum of 96 hours. | 
| Length of stay | Length of stay | Hospital admission maximum of 96 hours. | 
| Time to discharge readiness. | Time from admission to discharge readiness as assessed by physical therapy. | Hospital admission maximum of 96 hours. | 
| Transient Neurologic Symptoms | Any episodes of transient radiating pain in the buttocks and thigh will be recorded in the hospital charts during routine post operative rounds. This is also be discussed at the first follow up visit scheduled 2 weeks after surgery. | Hospital admission and first follow up visit. Data will not be recorded after 3 weeks from time of spinal |