Trochanteric Hip Fractures (AO A2) Treated With Sliding Hip Screw With or Without Trochanteric Stabilizing Plate - a Randomized Controlled Trial Using Radiostereometry.

Trochanteric fractures represent about half of the hip fractures (with femoral neck fractures as the other half), and are almost always treated surgically with internal fixation of the fracture. However, there is an ongoing debate on what is the appropriate implant to use. For stable fracture patterns the evidence seems to be in favour of the sliding hip screw, whereas for the unstable fractures it is unclear whether an intramedullary nail or a sliding hip screw with or without a lateral support plate should be the implant of choice. A series of studies is now planned at Oslo University Hospital in collaboration with Diakonhjemmet Hospital in hope to further clarify this debate. The use of the lateral/trochanteric support plate (TSP) is widespread in some regions (e.g. Norway, Sweden and parts of Britain), but virtually never used other places. The role of the TSP remains unclear and very little has been published on it's use, even though it is believed to be an important contributor of stability to the sliding hip screw construct.

Trochanteric fractures are mainly caused by a direct trauma, i.e mainly a fall from own height in the elderly. The fractures are most often classified using the Müller AO classification or the Evans/Jensen, but several other classification systems also exist. The ideal classification system should be easily applicable, reliable, and aid in treatment decision making.

The treatment of trochanteric fractures comprise perioperative and operative modalities. The perioperative modalities consist among others of medical optimalization preoperatively, early rehabilitation and prevention of new fractures by treating osteoporosis and preventing new falls. The main scope of the current study will, however, be the operative modalities.

Surgery for trochanteric fractures is performed mainly with fracture reduction on a traction table and internal fixation, using either an intramedullary (IM) nail or a sliding hip screw (SHS), both available in various designs from different manufacturers. The latest Cochrane review did not conclude on which implant is the superior. However, among stable fractures there are less reoperations with the SHS, mainly due to peri-implant femoral fractures after operation with an IM nail that. The more unstable fractures, namely the reverse oblique and subtrochanteric fractures, may obtain better results using an intramedullary nail, probably due to less secondary dislocations with resulting varus deformity, shaft-medialization and shortening. The evidence for this is, however, weak and the role of the TSP remains unclear.

Radiostereometry (RSA) is the most precise and accurate method to measure motion in vivo between different segments in orthopaedic research. To do so, radio-opaque tantalum markers are implanted into the bone defining different segments. Stereoradiographs are performed over time to detect movement and monitor the healing (or non healing) process. This movement can be calculated both as translations and rotations. They are ideal to describe and compare the stability of fracture systems. RSA has been used successfully in earlier studies on fracture healing. Due to the high accuracy and precision, RSA yield reliable results with relatively small study-groups. We plan to use RSA to measure fracture dislocation and time to healing in our studies.