THREE REGIONAL BLOCKING METHODS ASSESSMENT IN ARTHROSCOPIC ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

Andres BADER, Matías MEULI, Anibal VESCOVO, Gustavo GARCÍA FORNARI

Hospital Italiano de Buenos Aires, Buenos Aires, Argentina.

Background and objectives:
Arthroscopic anterior cruciate ligament reconstruction (ACLR) is associated with moderate to severe postoperative (POP) pain with opioid requirement that may lead to discharge delay. Both, femoral (FNB) and subsartorial saphenous nerve block (SNB), have shown to be effective in pain management1, with no significant differences 2,3. Furthermore, the addition of obturator nerve block to the saphenous nerve block (ONB + S) would improve its efficacy. 
This study aim is to assess the association between POP pain and three different types of regional nerve blocks (FNB, SNB, ONB + S), opioid requirement and length of stay at recovery-room.
Methods: 
Observational, analytic, retrospective study of a patient cohort undergoing ACLR, who received three types of peripheral ultrasound-guided blocks from October 2016 to November 2017 at the Hospital Italiano de Buenos Aires. Data were obtained from electronic records. 
POP pain was defined as a Verbal Rating Scale (VRS) ≥ 4. VRS was measured at three times: immediate POP period (VRS 0), one hour after surgery (VRS 1) and at discharge (VRS D). Opioid requirement was defined as the need of opioids (tramadol and morphine) in the intra- and postoperative period. To evaluate the association between the type of block and the presence of pain, a multiple logistic regression was performed, adjusting for confounders, and crude and adjusted ORs (CI95%) were expressed. Level of significance of less than 5% was considered. The data were analyzed with STATA13. 
Results:
A hundred and forty-five (ASA I-III) patients who received three types of peripheral ultrasound-guided blocks (FNB n=48, SNB n= 32, ONB + S n=65) were included. 
No significant differences regarding opioid requirement among block groups (p=0.371) were observed, as well as with length of stay (p=0.19).
Furthermore, no significant differences among the three types of blocks and VRS 0 (p>0.05) were found (FNB: OR=1 CI95% 1, SNB: OR=1.07 CI95% 0.40-2.87 p=0.88, ONB + S OR=1.27 CI95% 0.56-2.89 p=0.56). Same results were obtained for OR adjusted by confounders (sex and opioid requirement). 
Conclusions:
No association was observed between the type of block and the presence of POP pain. There were no differences in opioid requirement or recovery-room period.
References:
1- Bonet A, et al. Rev Esp Anestesiol Reanim. 2015; 62(8):428-35.
2- Rahimzadeh P, et al. Turk J Anaesthesiol Reanim. 2017; 45(4):218-224. 
3- Chisholm MF, et al. HSS J. 2014; 10(3):245-51.

08 / Three regional blocking methods assessment in arthroscopic anterior cruciate ligament reconstruction