Management of Postoperative Pain After Total Knee Replacement.

Patients undergoing total knee replacement will be assigned at random to receive one of two
methods of postoperative pain management. Patients assigned to nerve block will receive
regional anesthetic nerve block using an indwelling femoral nerve catheter and a single shot
sciatic nerve block. Patients assigned to periarticular injection will receive periarticular
local injection into the periarticular soft tissues at the time of knee replacement using a
combination of ropivacaine, epinephrine, ketorolac, and morphine sulphate. Additionally, all
patients will be given a standardized combination of oral analgesic medications
preoperatively and postoperatively. All patients will receive a posterior stabilized total
knee replacement through an medial parapatellar approach.

Inclusion Criteria:

- Unilateral primary total knee replacement.

- Weight 50-125 kg.

- Age 18-79 years.

- Intact neurological exam to the surgical lower extremity.

- Cognitively intact with ability to sign informed consent.

Exclusion Criteria:

- Renal insufficiency with creatinine >1.5 mg/dL.

- Allergy to medication used in the study.

- Using narcotic medication prior to surgery (morphine equivalents >=20 mg/day for >7
days.

- Prior open knee surgery with regional anesthesia or periarticular injection for
post-operative pain management.