Ultrasound guided genicular nerve block: Anatomy and effectiveness of postoperative analgesia in knee artroscopic anterior cruciate ligament repair surgery

Aim: Genicular nerve block is defined as infiltration of the sensory branches innervating the knee joint before they enter the knee joint capsule. The inconsistency in the terminology and origin of genicular nerves in the literature may be related to variations in anatomical descriptions. The aim of this study was to provide the dissection of the genicular nerves and to evaluate the efficacy in postoperative analgesia in arthroscopic anterior cruciate ligament (ACL) repair by USG-guided blocking of identifiable nerves. Materials and Methods: In the first phase of the study, four cadaveric knees were dissected. N.obturatorius, n.ischiadicus, n.peroneus communis and n.tibialis branches were found. The genicular nerves of the knee joint capsule were demonstrated. In the second stage, 60 patients aged 18-75 years who were planned for ACL operation were included in the study. Patients were randomly divided into two equal groups. Group G; preoperative genicular block was applied from four different injection points, while no block was applied in Group K. All patients were operated under general anesthesia. Postoperative fentanyl IV patient-controlled analgesia was administered. Postoperative VAS scores at rest and motion, analgesic drug consumption and the presence of side effects were measured at 1-6-12-24 hours. Results: Superior medial and lateral genicular branches originated from n. tibialis, inferior lateral branches originated from n. peroneus communis, inferior medial branches originated from n. tibialis and some nerve branches originated from n. saphenus and participated in sensory innervation. In our clinical study, additional analgesic requirement was observed in Group K at all times. Postoperative VAS values were lower in Group G at 1,6,12 and 24 hours. Conclusion: The knee joint capsule has a very rich nerve network. Genicular block should be considered as a good postoperative analgesia option after ACL repair surgery.