Comminuted displaced fractures of the patellar which are difficult to reduce accurately and to get stable internal fixation, may lead to traumatic osteoarthritis, chondromalacia, extension lag and limited ROM of the knee joint. The authors studied thirty eight parients with patellar fractures, who were treated by operative methods and a follow up of more than six months between Jan. 1984 and Dec. 1988. Three were thirty-three male and five female. The ages ranged from 18 to 78 years, the average being 41.6 year Twenty patients were caused by traffic accidents, eleven slip down, four fall down, and three direct trauma. The pattern of fracture was comminuted fracture in twenty-one cases, transverse fracture in thirteen cases and vertical fracture in four patients. Ten patients had associated fractures or other organ injuries. Twenty five patients were treated by open reduction and internal fixation, (10 circumferential wiring, 7 oircurnferential oFiring and K-wire fixation, 6 tension hand wiring and 2 screw fixation). Thirteen patients were treated by patellectomy (11 partial and 2 total patellectomy). Of thirty-three cases except 5 cases, the average time to union following to pattern of fracture were 8 weeks in transverse fracture, 7.5 weeks in vertical fracture and 12.7 weeks in comminuted fracture. There were nine complications;3 refracture, 3 wire breakage, 2 extension lag and 1 malunion.