Relatively poor results have been reported with open reduction and internal fixation of complex fractures around the knee in elderly osteoporotic patients, and primary total knee arthroplasty (TKA) has been proposed as an alternative solution. While limiting the number of procedures, it meets two prerequisites: (1) to save the patient's life, thanks to early weight-bearing, to limit decubitus complications; and (2) to save knee function and patient autonomy, thanks to early knee mobilization. There are 3 main indications: complex articular fractures in elderly patients with symptomatic osteoarthritis prior to fracture; complex articular fractures of the tibial plateau in elderly patients whose bone quality makes internal fixation hazardous; and major destruction of the distal femur in younger patients. Although admitted in emergency, these patients require adequate preoperative management, including a multidisciplinary approach to manage comorbidities, control of anemia and pain, and assessment and management of vascular and cutaneous conditions. Preoperative planning is crucial, to order appropriate implants and materials that may be needed intraoperatively. Surgical technique is based on the basic principles of revision surgery as regards choice of implant, steps of reconstruction, bone defect management and implant fixation. For complex fractures of the distal femur, primary temporary reduction is a useful ``trick'', to determine the level of the joint line and femoral rotation. Complementary internal fixation may be required incase of diaphyseal extension of the fracture and to prevent inter-prosthetic fractures. In the literature, the results of primary TKA for fracture are encouraging and better than for secondary TKA after failure of non-operative treatment or internal fixation, with lower rates of revision and complications, earlier full weight-bearing and better functional results. Loss of autonomy is, however, frequent, and 1-year mortality is high, especially following complex femoral fractures in the elderly. (c) 2017 Elsevier Masson SAS. All rights reserved.