Study of Pain Management Techniques Following Anterior Cruciate Ligament Repair Surgery

patients enrolled in the study will receive subsartorial saphenous nerve block in all the three groups. Patients in group 1 will receive perimuscular injections around the gracilis and semi-tendinosus muscles. The needle is redirected to the fascial plane between Sartorius and gracilis muscle after the sub-sartorial canal block where 7.5 ml of 0.5% ropivacaine is injected around the muscle. The needle is further advanced to the fascial planes between semimembranosus and semitendinosus and an additional 7.5 ml of 0.5% ropivacaine will be injected around the semitendinosus muscle. Following this a sham injection of 10mL of saline for the anterior division of obturator nerve will also be performed as in group 2 to ensure blinding.

Patients in group 2 will receive anterior division of obturator nerve block along with subsartorial canal block. After ensuring aseptic precautions, the saphenous nerve block is performed similar to that as in group 1. The anterior branch of obturator nerve will be visualised in the proximal thigh medial to femoral vessels between adductor longus and adductor brevis. A 22 gauge 90 mm PNS block needle will be inserted under ultrasound guidance to reach the anterior division of obturator nerve confirmed with neurostimulation followed by injection of 10 ml of 0.5% ropivacaine around the nerve. This group will receive sham injection of 15mL of saline around semitendinosus and semimembranosus as in group 1

The patients in group 3 will form the control group. After performance of the subsartorial saphenous nerve block, patients in group 3 will receive sham injections of saline for the obturator nerve block and the hamstrings block (perimuscular injections).