Purpose: While several studies have reported improved pain control with use of femoral nerve blocks (FNB) following ACL reconstruction, there are few studies that have evaluated the effect of continuous perineural infusion on quadriceps activation and recovery of range of motion after ACL reconstruction. The purpose of this prospective randomized placebo-controlled clinical trial was to determine if the use of continuous infusion of levobupivacaine for pain control following ACL reconstruction had an adverse effect on postoperative quadriceps activation and recovery of ROM.

Method: Two-hundred-seventy patients underwent ACL reconstruction and were randomly assigned to one of three FNB groups (placebo bolus and infusion, active bolus with placebo infusion, or active bolus and continuous infusion). The patients’ ability to perform a SLR was assessed daily for the first four post-operative days. Range of motion of the knee was measured with a goniometer 1, 4, 8 and 12 weeks after surgery. Range of motion complications requiring arthroscopic debridement, manipulation under anesthesia, or application of a drop-out cast were recorded.

Results: There were no significant differences between groups in their ability to perform a SLR on postoperative day 1 through 4. There were also no differences between active and passive ROM values between groups at each follow-up period. There were 7 (3.2%) early ROM complications, but no detectable differences between groups.

Conclusion: Continuous perineural infusion of levobupivacaine (0.25% at 5mL/hr for 50 hours) following ACL reconstruction does not appear to negatively influence quadriceps activation as evidenced by the inability to perform a SLR or adversely affect recovery of range of motion in the early postoperative period after ACL reconstruction. Continuous perineural infusion can provide effective pain relief without adversely affecting post-operative recovery following ACL reconstruction.