Effectiveness of Ultrasound-guided versus Anatomical Landmark-guided Genicular Nerve Block to Treat Chronic Knee Osteoarthritis: A Retrospective Cohort Study oleh Sarbhjit Singh, Sarbhan Singh, Maniventhan Nachimuthu, Ahmad Fauzey Kassim, Avreena Kaur Bhullar, Rajkumar Veerakumaran, Goh Ni Kol, Nurul Azreen Mohd Roslan