The knee joint has four crucial ligaments: the anterior and posterior cruciate ligaments, and the medial and lateral collateral ligaments. They act like four pillars, firmly anchoring the knee joint in a very stable and normal position. If any of these ligaments rupture, this balance is disrupted, causing the knee to move abnormally in a certain direction, leading to increased local wear and tear or compensatory wear in other parts. Therefore, if ligament damage is not repaired, and the balance is disrupted, it can lead to many complications or sequelae. The first is traumatic arthritis. The second is patellar chondromalacia. The third is meniscus damage. The fourth is damage to other ligaments, or even rupture. The fifth is knee arthritis, also known as OA, or degenerative changes. The sixth is knee effusion and synovitis. Thus, the sequelae of knee ligament injuries are numerous and troublesome.