We present the case of a 78-year-old rheumatoid patient with a bifocal stress fracture of the pubic rami after ipsilateral total knee arthroplasty. Many risk factors that may cause insufficiency fractures are combined in rheumatoid arthritis. These patients are used to chronic pain, and therefore the diagnosis is often made late. When a patient suffering from rheumatoid arthritis presents with recent pain in the pelvic or hip region after hip or knee arthroplasty, a stress fracture should always be suspected. A standard pelvic radiograph and skeletal scintigraphy establish the diagnosis. CT-scan may be useful in the differential diagnosis with less benign pathology. Rest and analgesic drugs are sufficient to let the fracture heal. Nonunion has never been reported for these fractures.