Simultaneous operations on the lower extremities may potentially benefit some patients. However, the only literature discussing simultaneous operations has been limited to bilateral simultaneous total hip or knee replacements. The cases of 10 patients who had combined joint arthroplasty (8 knee, 2 hip) and foot and ankle arthrodesis (6 subtalar, 4 ankle) were reviewed retrospectively. Combining the procedures allowed the patient to have autologous bone brought from the joint replacement site to the foot or ankle to assist in filling defects in the arthrodesis. The fusion rate of 100% and the good results of hip or knee replacement demonstrate that successful treatment is possible when both conditions are treated simultaneously.