Background: To highlight the higher incidence of sub-trochanteric fracture following cannulated screws fixation for the neck of femur fracture, which may be due to surgical errors and osteoporotic bone

Method: Illustrative case report of a 78 years old demented independently mobile female patient who was admitted with an intracapsular Neck of Femur fracture, treated with cannulated screws. 2 weeks post operatively, she developed subtrochanteric undisplaced proximal femoral fracture without any trauma. She was treated with cemented hemiarthroplasty.

Conclusion: The valgus impacted neck of femur fracture, treated with cannulated screws is associated with some inherent problems. The cannulated screws can become incarcerated during initial open-reduction internal fixation and break. The incidence of subtrochanteric fracture following hip operation is greater with an entry point in the lateral cortex below the level of the most inferior edge of the lesser trochanter. Although in our case study, we placed the screw above the lesser trochanter. It has been reported that two screws in the inferior part of the femoral neck create a stress riser in the sub-trochanteric region, potentially inducing a fracture in the weakened bone, and it may be induced by a trauma. In this case study failure may be due to multiple drill holes on the lateral cortex during insertion of the guide wire [fig 2].

Subtrochanteric fracture following cannulated screws may occur without trauma. Osteoporosis may have a major role to play. We recommend one screw infe-riorioly and entry point above the lesser trochanter as reported previously.