Reduced Opioid Use after Surgeon-Administered Genicular Nerve Block for Anterior Cruciate Ligament Reconstruction in Adults and Adolescents

Abstract

Background

Pain management after anterior cruciate ligament reconstruction (ACLR) may pose a risk of prolonged opioid use.

Questions/Purposes

The purposes of this study in ACLR were to investigate the efficacy of a surgeon-administered local–regional block of specific genicular nerves on post-operative analgesia following ACLR and to quantify the outpatient opioid consumption and duration through the complete post-operative course.

Methods

Prospectively, all patients undergoing primary ACLR by a single surgeon were studied over a 10-month period. Exclusion criteria consisted of history of pre-operative opioid use, revision surgery, multi-ligament surgery, allergy to oral opioids, and allergy to local anesthetic. ACLR was performed using autograft or allograft patellar tendon bone (PTB) graft under general anesthesia. At the conclusion of the procedure, all patients received a local anesthetic (bupivacaine 0.25%) injection by the surgeon including a unique circumferential genicular nerve and fat pad block performed based on anatomic landmarks without use of image guidance. Post-operatively, the quantity and duration of opioid use (hydrocodone 5 mg) and pain scores were recorded for 4 months prospectively. Statistical analysis was performed to evaluate risk factors for increased opioid use.

Results

A single surgeon performed 75 ACLRs. After exclusions, a total of 70 patients were enrolled and followed prospectively. None were lost to follow-up. Total opioid consumption ranged from 0 to 30 tablets. The average number of opioid tablets used over the 4-month post-operative course was 5.5 (± 6.7). After surgery, 84% of patients took between 0 and 10 tablets and 21% of patients took no opioids throughout their entire post-operative course. The average duration of consumption was 2.6 days (± 3.1). No patients were taking opioids at the 6-week or 4-month follow-up. There were no refills required. No statistically significant differences were seen in regard to graft choice of autograft PTB (n = 48) vs allograft PTB (n = 22) in total opioid consumption or duration of use. In comparing adolescent (n = 31) versus adult (n = 39), no significant difference was seen in total opioid consumption or duration of use. All patients were satisfied with the post-operative pain management protocol.

Conclusion

Opioid use was unexpectedly low among patients undergoing ACLR after a surgeon-administered circumferential genicular nerve block and fat pad infiltration. With this protocol, the graft choice and patient age did not correlate with increased opioid use. These results could be useful in guiding post-operative opioid prescribing after ACLR.