“…There are two types of lipomas, true lipoma and lipoma arborescens. Basically, intra-articular true lipoma is so rare, with only dozens of cases reported in the literature up to now [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. Clinically, most of the patients with intra-articular lipoma are asymptomatic, some show as pressure symptoms caused by mass lesions, such as locking, kneeling pain, and so on.…”