Here, we report three cases of infected nonunion of distal femur area with massive bone loss and extensor mechanism impairment after a series of debridement procedures and sequestrectomies among the elderly. These cases were successfully treated with arthrodesis type megaprosthesis. For providing immediate stability and better function for ambulation, we chose the mentioned megaprosthesis for definite treatment. Although the flexion- extension function of the knee was compromised in these patients, they exhibited full weight-bearing ambulation postoperatively. Arthrodesis-type megaprosthesis may be an alternative treatment option for infected nonunion of the distal femur area with massive soft tissue and bone loss after infection control in the elderly.