Effects of Continuous Nerve Block vs Single Injection Block With PCA vs PCA on Pain and Function After Knee Replacement

Effects of Continuous Femoral Nerve Block Versus Single-Injection Femoral Nerve Block With Intravenous Patient Controlled Analgesia Versus Intravenous Patient Controlled Analgesia on Knee Pain and Function After Total Knee Replacement

The purpose of this study is to compare the effectiveness of three analgesia techniques on pain relief and functional recovery after knee replacement: continuous femoral nerve block vs single-injection femoral nerve block with intravenous patient controlled analgesia vs intravenous patient controlled analgesia.

Primary Outcome Measures:

• Incidence of patients with significant pain on movement on day 1 post surgery
• Range of knee flexion

Secondary Outcome Measures:

• Pain intensity (rest/movement)
• Functional recovery
• Knee Injury and Osteoarthritis Score
• Side effects/ Adverse outcomes
• SF12 Quality of Life Questionnaire
• Length of stay

Inclusion Criteria:

• 40 years and above
• Osteoarthritis
• Primary unilateral total knee replacement
• No other lower extremity joint disease
• ASA I-III
• Body mass index < 35
• No severe cardiac or pulmonary diseases
• No chronic narcotic therapy or illicit drug use
• Mentally competent to understand study procedures and use of pain scales
• Able to provide informed consent

Exclusion Criteria:

• Any cause for knee replacement other than osteoarthritis
• Total knee revision
• Any contraindication for femoral block
• Abnormal coagulation studies
• Thrombocytopenia less than 100,000/cc
• Known hepatic or renal insufficiency
• Neurological disease involving lower extremities
• Major surgery during the last 2 weeks pre-operatively
• History of allergy to study medications
• History of post-operative bleeding over 2000 cc/24 hours
• History of opioid or alcohol abuse
• Currently taking or has taken opioid > 30 consecutive days of daily use at a daily dose > 15mg morphine, within the past 2 weeks prior to surgery
• Previously has not responded to opioid analgesics for treatment of pain
• Pregnancy or breastfeeding