Ultrasound-guided saphenous nerve block is an effective technique for perioperative analgesia in ambulatory arthroscopic surgery of the internal knee compartment.

Objectives: Arthroscopic knee surgery is a minimally invasive technique with moderate pain during the first 24h. Our main objective was to evaluate the efficacy of ultrasound guided saphenous nerve block as a method of pain control intraoperatively and postoperatively for this surgery.

Material And Methods: A prospective and observational study. All patients received general anesthesia with laryngeal mask in the saphenous group, nerve block was performed with 10 ml ropivacaine 0.475%. Location of the surgery (external compartment group/internal compartment group), morphine consumption, VAS for pain at 5, 30, 60 and 120 min and 24 h after surgery, need for rescue medication, onset of nausea and vomiting, length of stay in PACU, delayed discharge and satisfaction were evaluated.

Results: The study included 73 patients. Of these, 46 received saphenous nerve block and 27 didn't receive it. Consumption of intraoperative, postoperative and total morphine was significantly lower in the saphenous group as well as VAS at 24h. In the subgroup of internal compartment surgery differences in VAS 24 h, morphine consume and lenght of stay in PACU were mantained.

Conclusions: The ultrasound-guided block of saphenous nerve, particularly in the internal compartment arthroscopic knee surgery, decreases analgesic requirements, obtaining more effective pain control in the first 24 h postoperatively and without any known side effects.