The knee still hurts 100 days after the fall, considering the soft tissue injury or fracture of the knee joint caused by trauma, and may also be due to fractures, ligament injuries caused by prolonged immobilization of the knee joint, traumatic arthritis and other soft tissue adhesions. 1. Soft tissue injury: for superficial soft tissue contusion, the recovery time is relatively fast, but if the meniscus injury inside the knee joint, ligament cracks, etc., the recovery is slow, which may lead to a fall 100 days of time still hurts. 2. Knee fracture: the more common patella fracture, tibial plateau fracture, etc., belongs to the sequelae of the fracture, but also does not exclude the possibility of poor fracture healing. 3. Adhesion: mainly seen after knee trauma, especially ligament tear, fracture, after surgery to give external fixation, the knee joint is fixed for a long time, resulting in soft tissue adhesion around the knee joint, the knee joint pain will occur during activities. 4. Traumatic arthritis: mainly after a fall on the knee joint, leading to degeneration of the cartilage inside the knee joint, which in turn leads to inflammation of the knee joint by wear and tear, and pain can appear 100 days after the fall. It is recommended to go to the hospital in time to improve the auxiliary examination, in order to clarify the cause of the disease, the professional physician for treatment.