Continuous femoral nerve block has no impact on postop ACL function

Level 1 trial finds that 48 hours of continuous infusion offered pain relief, no impact on ROM.

CALGARY — Continuous femoral nerve block may provide sustained pain relief after ACL reconstruction without hindering postoperative quadriceps function or range of motion.

In a level 1 clinical trial, investigators at University of Pittsburgh Medical Center studied 217 patients who underwent ACL reconstruction and received either saline, a single-dose of levobupivacaine (Chirocaine, AstraZeneca) or a continuous infusion of levobupivacaine for 48 hours. The study revealed no significant differences between the groups regarding the number of patients able to perform straight-leg raises during the first 4 days postop.

The investigators also found no significant differences between the groups for overall flexion and loss of extension at 1, 4, 8 and 12 weeks postoperatively. During the study, they discovered that seven patients required manipulation or arthroscopic debridement for loss of motion. But they found no significant differences in the rate of patients needing intervention between the groups.

Multidisciplinary cooperation

"We found that continuous femoral nerve block is a safe and effective method of pain control with no significant effect on quadriceps function or range of motion," Susan S. Jordan, MD, said during her presentation at the American Orthopaedic Society for Sports Medicine 2007 Annual Meeting. "It remains a standard component of our ACL practice. We would like to point out that successful incorporation of this protocol requires multidisciplinary cooperation between the team of anesthesiologists, surgeons, nurses and patients."

The team of investigators, which included Christopher D. Harner, MD, Jay Irrgang, PhD, Brian Williams, MD, Alex J. Kline, MD and Jordan, evaluated 217 patients who underwent primary ACL reconstruction using single-bundle procedures. Patients received a 48-hour course of either:

a saline bolus followed by a saline infusion (75 patients);
a 0.25% levobupivacaine bolus followed by a saline infusion (72 patients); or
a 0.25% levobupivacaine injection followed by a continuous infusion of levobupivacaine (70 patients).

The study contained patients with a mean age of 27.8 years and a mean body mass index of 26. Men comprised 57.6% of the overall study group and there were no significant differences between the groups regarding patient demographics.

No significant differences

The investigators discovered that 80% to 90% of all study patients could perform straight-leg raises during the first 4 days postop with no significant differences between the groups. Similarly, the study revealed no significant differences between the cohorts for loss of extension during follow-up.

"There were no significant differences between the groups with respect to overall flexion and there was a tendency towards increasing flexion as time progressed," Jordan said. "In terms of loss of motion that required intervention, overall, there were seven of our 217 patients or 3.2% who required intervention, which is either manipulation or arthroscopic debridement. There were no significant differences between the groups with respect to this complication."

For more information:
Susan S. Jordan, MD, can be reached at UPMC Center for Sports Medicine, 3200 South Water Street, Pittsburgh, PA 15203; 412-432-3662; e-mail: jordanss@upmc.edu. She has no direct financial interest in any products or companies mentioned in this article.
Radkowski CA, Irrgang JJ, Kline AJ, et al. Effect of femoral nerve blocks on postoperative range of motion and quadriceps function after ACL reconstruction. Presented at the American Orthopaedic Society for Sports Medicine 2007 Annual Meeting. July 12-15, 2007. Calgary.