Background and aims The choice of regional analgesia technique for anterior cruciate ligament reconstruction (ACLR) remains controversial. The nerve to vastus medialis (VMN) is very important in knee sensory innervation, but it lies outside the adductor canal (AC) and can be difficult to identify using ultrasound. In this pilot study we evaluate the effect of VMN block using neurostimulation in addition to IPACK and AC block for postoperative analgesia in ACLR.

Methods Eleven consecutive patients were submitted to general anesthesia with sevoflurane and laryngeal mask airway. IPACK block with 20–25 ml of ropivacaine 0,5% was done as described by Sinha et al. After this, the AC was identified as suggested by Wong et al. For VMN block, the needle was introduced in-plane and directed to AC, looking for this nerve superficial to vastoadductor membrane (VAM), between the sartorius and vastus medialis muscle (VMM). The correct nerve identification was confirmed by adequate response (VMM contraction) using nerve stimulation (0,5 mA). Five milliliters of anesthetic solution were injected. Then the needle was advanced until it pierced the VAM and penetrated the AC. More five milliliters were injected next to the saphenous nerve.

Results The VMN was identified in all cases. Nine patients did not need any analgesic rescue during the postoperative period, and two patients needed one rescue dose (tramadol 50 mg). All patients were able to begin the rehabilitation program next morning with minimal pain

Conclusions VMN block using neurostimulation associated with IPACK and adductor canal block seems to be a good alternative for postoperative analgesia in ACLR.