This syndrome is also an unfamiliar name to everyone and can also cause painful discomfort in the joint that can be relieved with rest and is often confused with prepatellar fat pad entrapment syndrome. The synovial crease is a remnant of fetal birth within the eh, mainly the suprapatellar, infrapatellar and medial patellar creases, etc. 20% of normal people can have synovial creases, which generally do not cause symptoms. 1, etiology: generally does not cause symptoms, if the synovial membrane swollen hyperplasia, stuck to the joint space will cause symptoms, common causes are trauma, chronic strain, inflammation, trauma and so on. 2. Main manifestations: Most of them have a history of knee strain or trauma, and there is a disorder within the knee joint, which can occur repeatedly. The pain can be soreness of the whole knee, or pain below the front or inside of the knee, which is aggravated by strenuous activity, obvious when going up and down stairs, jumping, sometimes accompanied by a popping sound, some patients have friction sounds or friction sensation, some can also have obvious joint effusion, joint pressure pain is mainly located in the medial patella, when the joint flexion and extension from 0-90 degrees in the medial patellofemoral joint can be felt thickened synovial folds in the form of cords, activity When the elastic ringing is obvious, it should be distinguished from the elastic ringing caused by meniscal injury. 3, treatment: first of all, avoid aggravating the injury, pay attention to rest, reduce activity, try not to go up and down stairs, encourage quadriceps training, local topical medication to reduce swelling; if recurring arthroscopic surgery can be removed, of course, can also be closed treatment, but easy to recur.