Multi-ligament knee injury, involving complex destruction of structures like the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL), presents significant challenges in treatment as well as diagnosis. This case study focuses on a 55-year-old woman who was the victim of a severe traffic accident and had an ACL and PCL avulsion fracture, a medial condyle fracture, and a medial collateral ligament rupture. Afterward, open reduction and internal fixation of the right tibial plateau surgery was performed after a delay in order to manage the pain and swelling. Her rehabilitation was greatly helped by postoperative physical therapy, which focused on pain control, early mobilization, and gradual strength development. A well-structured rehabilitation plan was found to be beneficial, as indicated by the remarkable improvements in pain reduction and functional mobility. This case highlights the value of effective physical therapy in helping patients through the difficult recovery process following multiple ligament injuries with the goal of restoring function and improving their quality of life.