Continuous Femoral Nerve Blockade and Readiness to Discharge Following Total Knee Arthroplasty

The Secret Recipe for Femoral Nerve Blockade After Total Knee Arthroplasty: A Randomized, Placebo-controlled, Double-blind Trial

Patients undergoing total knee arthroscopy (knee replacement) surgery usually receive a femoral nerve block as part of their anesthetic care. Some centers administer the block with a single shot of local anesthetic, which wears off several hours after surgery. Other centers administer the block with a single shot followed by continuous infusion of local anesthetic, typically for 2 to 5 days after surgery. The latter method, though good for pain control, may result in decreased mobility (while the anesthetic is still active), longer hospital stays, and greater risk of falls.

This study will see if using a lower concentration of local anesthetic for the continuous femoral nerve block or only the initial single-shot dose will result in increased mobility and shorter hospital stays.

Inclusion Criteria:

1. ASA physical status I-III
2. 18-85 years of age, inclusive
3. Able to communicate in English sufficiently to participate in the study
4. Able to walk 30 metres without stopping prior to surgery

Exclusion Criteria:

1. Intended discharge to in-patient rehabilitation facility
2. Patient refusal of FNB or spinal anesthetic or sciatic nerve block
3. Contraindications to peripheral nerve block (e.g. allergy to local anesthetics, refusal)
4. Significant peripheral neuropathy or neurological disorder affecting the lower extremity
5. Contraindication to a component of multi-modal analgesia
6. Pregnancy
7. History of use of over 30mg oxycodone or equivalent per day (institutional threshold for acute pain service consultation pre-operatively)
8. History of significant cognitive or psychiatric condition that may affect patient assessment
9. Inability to provide informed consent