Fracture of the femoral adapter bolt and taper adapter in a modern rotating platform knee arthroplasty

A 58-year-old woman presented with onset of pain associated with a popping sound after a twisting motion 4 years after left total knee revision arthroplasty. She had a complex medical history, including a reported bone cement allergy, and presented to the hospital unable to bear weight. Plain radiographs revealed a broken femoral component, with the femoral metaphyseal sleeve separated from the distal articular component. During surgery, it was observed that the femoral adapter bolt and taper adapter had both fractured. Scanning electron microscopy of the fracture surfaces of the components confirmed that the implant had failed in fatigue, presumably due to high cyclic loads. Failure at this junction has not been described previously. In this type of knee design, we recommend supporting the distal articular component either with bone, augmentation, and/or bone cement to reduce the risk for this mode of failure.