Pain Control after Total Knee Arthroplasty: Comparing Intra-Articular Local Anesthetic Injection with Femoral Nerve Block

Background. Direct intra-articular injection of low doses of local anesthetic (IALA) after closure of the joint capsule remains controversial for pain control after total knee arthroplasty (TKA). Methods. A retrospective study comparing patients receiving IALA with high doses (0.5% bupivacaine 60 mL) of local anesthetics or FNB in addition to intravenous patient-controlled analgesia with opioids for pain management after TKA was conducted. The primary end point was to compare the analgesic efficacy and early ambulation between the two groups. Results. No significant differences between the two groups in pain intensity, cumulative opioid consumption, incidences of opioid-related side effects, the time interval from the end of operation to the first time the patient could walk assisted with a walker postoperatively, and postoperative hospital stay were identified. Three patients in the IALA group but none in the FNB group walked within 12 hours after the end of operation. Summary. IALA with high doses of local anesthetics provides comparable analgesic efficacy as single-shot FNB after TKA and might be associated with earlier ambulation than FNB postoperatively.