Introduction
blood loss, fracture, traumatic, fractures, femur intramedullary nail
BLOOD LOSS, FRACTURE COMPRESSION
Hip fractures with their increasing frequency and severity have become a significant burden to the public health care systems worldwide. According to global epidemiological projections, the annual incidence of hip fractures will increase from 1.66 million on 1990 to 6.26 million by 2050 [The most common surgical treatment options for peri-trochanteric fractures are the internal fixation using the sliding hip screw system with plate and screws (SHS) and the intramedullary nail using a proximal femur intramedullary nail (IM nail). The use of the IM nails have been increasing the last two decades. The main benefits of IM nails are the less traumatic minimally invasive insertion, the shorter operative time and the reduced intra-operative blood loss. Biomechanically the IM nails have reduced lever arm and can substitute the lateral wall of the proximal part of the femur, presenting a theoretical mechanical advantage comparing to the SHS. On the other hand the application of a sliding hip screw system provides a continuous fracture compression while the patient bears weight. In many countries SHS systems have reduced cost and present comparable clinical outcomes with the IM nails [Despite the latest advances of the IM nailing systems, some technical aspects remain uncertain and require more investigation. In some nails, there is an option of applying a second (anti-rotation) lag screw into the femoral head. Biomechanically, the second lag screw provides more stability to the fixation, especially in unstable fracture patterns [