Liposomal bupivacaine (LB) is at least as effective as femoral nerve block (FNB) for managing pain after anterior cruciate ligament (ACL) reconstruction, researchers said here on March 1 at the 2016 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS).
Femoral nerve block is the mainstay for pain management after knee surgery, but it may cause nerve injury, delayed quadriceps activation, and residual quadriceps weakness.
Kelechi R. Okoroha, MD, Henry Ford Health System, Detroit, Michigan, and colleagues randomised 100 patients undergoing primary ACL reconstruction to receive either intraoperative local infiltration of LB (20 cc bupivacaine/10cc saline) using a standardised injection protocol or preoperative FNB.
Following surgery, patients were asked to record their pain levels (Visual Analog Scale [VAS]) and opioid consumption for 4 days. The primary endpoint of the study was postoperative pain levels
The data demonstrated a significant increase in pain in the LB group between post-operative hours 0 to 8 (mean 6.3 vs 4.8; P = .01). However, there was no significant difference between average daily pain levels in the 2 groups on each postoperative day (POD) 0 (mean 6.1 vs 5.4; P = .10), POD 1 (mean 5.5 vs 5.4; P = .97), and POD 2 (mean 4.5 vs 4.5; P = .52).
There was also no significant difference in average IV morphine equivalents consumed between the LB and FNB groups on POD 0, 1, and 2.
Patients receiving a FNB had a greater number of sleep disturbances on POD 0 (4.4 vs 3.1) and were more likely to call their doctor the following day due to pain (29% vs 8%).
There was no significant difference in satisfaction with pain management between the groups.
“The findings suggest that local infiltration anaesthesia with LB may be employed to provide similar overall pain control as FNB after ACL reconstruction without the risk of nerve irritation,” reported Dr. Okoroha.
He added that because of the significant increase in pain in the LB group between 0 to 8 hours postoperatively, patients receiving LB might benefit from a supplemental anaesthetic to cover the acute postoperative period.