Mepivacaine Versus Low-Dose Bupivacaine For Primary Total Hip and Knee Arthroplasty

Inclusion Criteria:

- American Society of Anesthesiologists (ASA) physiological status I-III (patient must
meet criteria of a status I-III in the ASA Physical Status Classification System:
I=Normal Healthy Patient, II=Mild Systemic Disease, and III=Severe Systemic Disease)

- Unilateral primary TKA or THA

- 18+ years of age

- Able to provide informed consent

Exclusion Criteria:

- Chronic pain syndromes such as fibromyalgia or complex regional pain syndrome

- Chronic opioid use (>1 mos) with OME >5 mg/day OR acute opioid use (< 1 mos) with OME
> 30 mg/day.

- Body mass index (BMI) > 45 kg/m2

- Severe drug allergy* to medications used in this study, including non-steroidal
anti-inflammatory drugs (i.e. celecoxib and ketorolac), and local anesthetics (defined
as an immune reaction resulting in shortness of breath, hives, anaphylaxis, wheezing,
and fever)

- Major systemic medical comorbidities such as:

- Pre-existing severe renal disorder defined as glomerular filtration rate (GFR)
<50 units/m2 (if labs are available), currently on dialysis, or highly suspected
based on history.

- Severe hepatic disorder defined as current or past diagnosis of acute/subacute
necrosis of liver, acute hepatic failure, chronic liver disease, cirrhosis
(primary biliary cirrhosis), chronic hepatitis/toxic hepatitis, liver abscess,
hepatic coma, hepatorenal syndrome, other disorders of liver

- Contraindication to spinal anesthesia technique (e.g., known spinal stenosis,
coagulopathy, sepsis, infection at site of injection, uncooperative, refusal,
anticoagulation medications not held within appropriate time frame*). *Per ASRA
guidelines, Clopidogrel (Plavix) held for at least 7 days, Dabigatran (Pradexa) held
for at least 5 days, Rivaroxaban (Xarelto)held for at least 3 days, Warfarin
(Coumadin)held for at least 5 days or recent INR of less than 1.4, Enoxaparin
(Lovenox) with doses > 1 mg/kg held for close to 24 hours.

- Known to be currently pregnant or actively breastfeeding. Patients that have a
previous history of menopause, hysterectomy, or tubal ligation will not be required to
perform a pregnancy test. Female patients that do not meet this criterion will be
asked to submit a urine sample, and will require a negative urine sample in order to
proceed with study protocol. Urine sample be collected pre-procedurally.

- Impaired cognition