The amount of time needed to rest after an injury varies depending on the degree of cartilage damage to the knee. Knee cartilage injury mainly refers to damage to the articular cartilage and meniscus of the knee joint. In mild injuries, there is pain and mild swelling in the knee joint, but the knee joint can function normally and can bear weight, so it is recommended to reduce the weight of the knee joint and rest in bed for 1-2 months. If the cartilage tissue of the knee joint is severely damaged, or if cartilage tissue is peeled off, it is necessary to rest for at least 3 months because cartilage tissue is not renewable. During this period, patients need to pay strict attention to the rest and protection of the knee joint, if they continue to move, it will increase the weight on the knee joint and aggravate the injury, which is not conducive to the repair of the injury. In addition, patients need to keep the knee joint warm, as getting cold will also affect the repair of cartilage damage.