Secondary Subtrochanteric Fracture After Atypical Femoral Shaft Fracture Treated With Intramedullary Nail

Intramedullary (IM) nail fixation is widely used for the treatment of atypical fractures of the femoral shaft. The configuration and location of proximal interlocking screws are unique to each nailing system and maybe transverse or oblique in direction. The authors experienced two cases of incomplete secondary fractures at the subtrochanteric region after IM nail fixation for atypical femoral shaft fractures. The proximal screw fixation of the two cases was different from one another. One was fixed with a spiral blade plus transverse screw and the other was fixed using an oblique direction screw from the greater trochanter to the femoral neck base. Based on our experience, we recommend only using a proximal locking screw toward the head when using an IM nail for the treatment of atypical femoral diaphyseal fractures. An 82-year-old female patient who had been fixed with an IM nail for the treatment of atypical femoral shaft fracture 13 months ago visited the outpatient clinic with pain in the right hip joint for one month. Local hot uptake was observed at the proximal interlocking screw insertion site around the subtrochanteric region on bone scan. A simple removal of the proximal locking screw was enough to treat the incomplete fracture. A 79-year-old woman visited the emergency room for pain in the right hip joint. On the radiograph, the right femur was found to be fixed with an IM nail, and an incomplete fracture line around the lower border of the lesser trochanter was observed. This patient was treated by replacing the IM nail with a reconstruction nail. When using an IM nail for the treatment of atypical femoral shaft fractures, it is appropriate to insert only the screw toward the femoral head for proximal fixation to prevent secondary subtrochanteric fracture.