Fatigue fracture of an osteosynthesis plate

The implant made of TiAl6V4 was used to screw a fracture of the femur and fractured after 12 weeks due to fatigue. Normally, a fracture should be healed after 6 weeks so that the bone can bear weight again, thus plates of this type are not designed to be to be fatigue resistant. In the present case, however, bone healing was delayed due to the patient’s advanced age. The fatigue fracture started in the first thread and occupies almost the entire cross-section to the left of the hole. On the right side, the presumed secondary fatigue fracture only traversed approximately 1/3 of the wall thickness before the ductile overload fracture occurred. Whether the mechanical damage in the area where the fracture started was caused by rough handling e.g. during installation and served as a crack initiation or was caused by subsequent hammering, could not be clarified in the end.