Background

Adductor canal block (ACB) and local infiltration (LI) at the surgical site and graft taken area have been both demonstrated efficacy in postoperative pain control after arthroscopic assisted anterior cruciate ligament reconstruction (ACL). LI is uncomplicated and manageable by the surgeon. However, the effectiveness is remaining unclear. The primary objective was morphine consumption within 48 hours following arthroscopic assisted ACL reconstruction with semitendinosus graft. The secondary objectives were postoperative functional outcomes, including numerical rating pain scale within 48 hours, patient satisfaction, quadriceps strength, range of knee motion after surgery, and complications.

Methods

We randomly assigned 48 patients who underwent primary arthroscopic assisted ACL reconstruction with semitendinosus graft to receive either post-operative ACB with 0.25% bupivacaine 20 ml or LI at the surgical wound, graft harvested site and intra-articular injection. The LI was a combination of morphine 3 mg plus ketorolac 30 mg and tranexamic acid 1 g. The primary efficacy outcome was postoperative morphine consumption recorded by intravenous patient-controlled analgesia device within 48 hours.

Results

A total of 48 patients (24 patients in each group) was recruited and analyzed. All patient’s baseline characteristics were comparable. The LI group showed a significant decrease in postoperative morphine consumption at 6 hours (median 0.11, IQR 0.05-0.14 mg/kg.) in ACB group compare with (median 0.04, IQR 0.01-0.06 mg/kg.) in LI group ; p=0.002, at 12 hour (median 0.16, IQR 0.13-0.21 mg/kg.) in ACB group compare with (median 0.09, IQR 0.04-0.15 mg/kg.) in LI group ; p=0.009, and 24 hours (median 0.23, IQR 0.17-0.32 mg/kg.) in the ACB and (median 0.16, IQR 0.08-0.23 mg/kg.) in the LI group; p=0.03, however, no significant decrease in cumulative morphine consumption in 48 hours (median 0.30, IQR 0.19-0.46 mg/kg.) in the ACB and (median 0.22, IQR 0.12-0.29 mg/kg.) in the LI group; p=0.066). There was no significant difference in postoperative pain score, quadriceps strength, and patient satisfaction.

Conclusion

The Local infiltration group could significantly reduce postoperative morphine consumption than in the Adductor canal block group at 6, 12, and 24 hours, but no significantly reduce postoperative morphine consumption at 48 hours postoperative pain control. However, there was no difference in postoperative pain score, quadriceps strength, and patient satisfaction.