Mepivacaine vs. Bupivacaine Spinal Anesthetic in Total Knee Arthroplasty
Mepivacaine vs. Bupivacaine Spinal Anesthetic in Total Knee Arthroplasty
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.
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.
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.