Introduction: Increasing number of osteoporotic fractures of the femur, especially upper part of the femur creates everyday problem of health services. Treatment of these fractures has been improving markedly during the past 25 years. DHS, gamma nail and some other implants are very useful in everyday surgery. However some of complications still can not be resolved like cut out. Osteoporotic fractures in subtrochanteric area represent even bigger challenging. Diaphyseal fractures are also difficult to be treated. The main problem is quality of osteoporotic bone. Plate with parallel screws doesn’t provide reliable fixation. Intramedulary nails, because of wide channel in distal femur area also don’t provide desirable fixation stability.

Material and Method: We analysed results of using of one new device: selfdynamisable internal fixator (SIF) in the series of 389 patients treated because of upper femur fractures. That device has possibilities of spontaneous dynamisation in two axes: along the femoral neck axis and along the diaphyseal axis. Spontaneous dynamisation in the diaphyseal axis is very important if diaphyseal or subrtochanteric fracture or comminuted fracture of the upper femur with subtrochanteric extension treated. For activation of axial dynamisation it not necessary to do any action from outside the body. This feature is activated spontaneously if there is no progress in fracture union within 6–8 weeks. This device provides three-dimensional fixation using clams and rod onto the lateral surface of the femur. The age of patients was from 59 to 87 years. This internal fixator is applied using minimally invasive method – by one or two small incisions.

Results: During the treatment it has been confirmed working of self-dynamisation concept. Spontaneous dynamisation in the long axis of the femur has been proven in 21% of patients with subtrochanteric and diaphyseal fractures and it has been proven radiologically that sliding happened between 1–4 mm (average 2.5 mm). Such dynamisation together with 3D configuration of screws resulted in relatively quick fracture healing. Follow up was 19 months (6–60). Altogether 97.6% fractures healed within normal healing time. There were 1 infection, 2 cut out, 1 mechanical complication, 4 delay unions and one non-union.

Conclusion: According to results obtained, it can bee concluded that new biological internal fixator is suitable for minimally invasive technique, without opening of fracture site.