The inability to straighten the leg five months after a fall on the knee may be due to meniscus or ligament injuries, etc. Keeping the leg pressed is usually not restorative and may require treatment such as surgery. There are a variety of possible reasons why the knee is still not straight five months after a fall. If the meniscus in the knee joint is torn, it leads to the knee joint in even squeezing the meniscus, resulting in severe pain can not straighten; patella fracture, soft tissue contusion inside the knee joint, cruciate ligament injury, etc., may also lead to the knee joint can not straighten. The above factors can not straighten the knee, through the leg pressure is generally not able to restore the knee to a state that can be straightened, straightening may further aggravate the knee injury, it is recommended that further examination to clarify the cause. If the meniscus is torn, surgery may be needed; cruciate ligament injury requires immobilization, ligament reconstruction, artificial ligament and other treatment methods. Knee fall five months leg can not straighten, it is recommended to go to the regular hospital in a timely manner, to identify the cause, timely treatment.