Predicting surgical factors for unplanned overnight admission in ambulatory arthroscopic surgery of the knee: a prospective cohort in one hundred and eighty four patients

Surgeon-Performed Saphenous Nerve Block at the Medial Femoral Condyle for Arthroscopic Partial Meniscectomy and Meniscus Repair: A Randomized Control Trial

Introduction

With the rising number of arthroscopic partial meniscectomy and meniscus repair procedures performed in outpatient surgical centers, there has been significant interest in limiting postoperative pain and optimizing recovery. Postoperative pain is a common reason for admission at these surgical centers, and opioid-related mortality is becoming an increasing concern. A surgeon-performed saphenous nerve block (SNB) represents a promising adjunct treatment option for pain control. The purpose of this randomized controlled trial was to determine if an SNB would result in decreased postoperative pain and opioid usage compared to control following arthroscopic meniscus repair or partial meniscectomy.

Methods

We randomized patients between two groups: one receiving an SNB and the other without an SNB. The operating surgeon performed the SNB using a landmark-based approach at the medial femoral epicondyle/adductor hiatus with 5 mL of 1% lidocaine preoperatively and 5 mL of 0.5% ropivacaine postoperatively. Neither ultrasound nor nerve stimulator was utilized to confirm the success of the block. The visual analog scale was utilized to record pain preoperatively and in the immediate postoperative period, one day, and seven to 10 days postoperatively. The nursing staff in the post-anesthesia care unit monitored patient pain levels and provided pain medication accordingly.

Results

We enrolled 80 patients, with 40 patients in each group. There was no difference in age, sex, body mass index, or laterality between study groups. Overall, there were no differences between groups in preoperative or postoperative pain at any time. The average pain scores preoperatively were 2.78 in the experimental group and 3.05 in the control group (p=0.502). In the immediate postoperative period, pain scores were 1.57 for the experimental group and 2.66 for the control group (p=0.090). No statistically significant difference was detected in the number of patients requiring opioids postoperatively or in the morphine milligram equivalents (MME) provided to patients receiving opioids. Twelve patients in the experimental group received opioids in the immediate postoperative period while 18 patients in the control group received opioids (p=0.248). We observed no adverse events in patients from either group.

Conclusion

As a pure sensory nerve, the saphenous nerve is an excellent target for pain control without associated leg weakness. We utilized a low-resource SNB in knee arthroscopy for partial meniscectomy and meniscus repair as an adjunct therapy for postoperative pain control. This randomized controlled trial suggests that surgeon-performed blocks via a landmark-based approach are not effective in controlling pain or limiting opioid use in the immediate postoperative period. However, given our lack of confirmatory testing via ultrasound or nerve stimulation, a true nerve block may not have been achieved in all patients. We believe this adds to the external validity of this study, as these tools may not be readily available in all settings.