The knee bumped and bulged a bag may be caused by subcutaneous bleeding or tissue fluid mass, patella fracture, intra-articular ligament injury, etc., which needs to be treated according to the cause. 1. If the bag is caused by subcutaneous bleeding or tissue fluid mass, if the amount of fluid is small, follow the doctor’s instruction to apply Yunnan Baiyao and other medicines to activate blood circulation and eliminate blood stasis to promote the absorption of fluid; if the amount of fluid is large, puncture and drainage can be performed under the guidance of the doctor. 2. If the bag is caused by patellar fracture, it can follow the doctor’s instruction to apply the dehydrating agent such as mannitol, vitamin D and other drugs to promote bone healing; for serious comminuted fracture, and at the same time the existence of osteoporosis, it is feasible to cut and replace the internal fixation surgery. 3. For the bag caused by intra-articular ligament injury, if it is anterior and posterior cruciate ligament injury, reconstructive surgery can be considered; if it is a rupture of medial or lateral collateral ligament, repair surgery is feasible. It is recommended that people who have a knee bump and a bulging bag go to the regular hospital in time to clarify the cause of the disease and standardize the treatment under the guidance of the doctor.