Liposomal Bupivacaine Versus Femoral Nerve Block for Pain Control After Anterior Cruciate Ligament Reconstruction: A Prospective Randomized Trial.

PURPOSE: To compare femoral nerve block (FNB) versus local liposomal bupivacaine (LB) for pain control in patients undergoing anterior cruciate ligament (ACL) reconstruction.

METHODS: Eighty-five patients undergoing primary ACL reconstruction were assessed for participation. We performed a prospective randomized trial in accordance with the CONSORT (Consolidated Standards of Reporting Trials) 2010 statement. The study arms included either intraoperative local infiltration of LB (20 mL of bupivacaine/10 mL of saline solution) or preoperative FNB with a primary outcome of postoperative pain levels (visual analog scale) for 4 days. Secondary outcomes assessed included opioid consumption (intravenous morphine equivalents), hours slept, patient satisfaction, and calls to the physician. Randomization was by a computerized algorithm. The observer was blinded and the patient was not blinded to the intervention.

RESULTS: One patient declined participation; 2 patients were excluded after randomization. A total of 82 patients were analyzed. Outcomes showed a significant increase in pain in the LB group between 5 and 8 hours postoperatively (mean ± standard deviation, 6.3 ± 2.0 versus 4.8 ± 2.6; P = .01). There were no significant differences between the groups in mean daily pain levels, morphine equivalents, or patient satisfaction when we controlled for graft type, age, body mass index, and sex. Patients receiving an FNB had a nonsignificant increase in number of sleep disturbances on the day of surgery (mean ± standard deviation, 4.4 ± 3.7 v 3.1 ± 2.1; P = .09) and were more likely to call their doctor the following day because of pain (29% v 8%, P = .04). Six patients in the FNB group had either prolonged quadriceps inhibition or sensory disturbance. One patient in the LB group required reoperation for a flexion contracture.

CONCLUSIONS: An increase in acute postoperative pain was found with LB compared with FNB for post-ACL reconstruction pain control. After the acute postoperative period, there were no significant differences in opioid consumption or pain control. The occurrence of nerve irritation postoperatively was found to be higher in the FNB group.

LEVEL OF EVIDENCE: Level I, prospective randomized trial.