Fracture healing in osteoporosis

Osteoporosis is a polygenetic disease, which can be strongly modified by life style and underlying diseases, Affected persons are at high risk for fragility fractures due to altered bone mass and bone strength. Major risk factors are genetics, gender, age, bone density, immobilisation and underlying diseases which may cause secondary osteoporosis. Fracture healing is a complex process, which is dependent on the regenerative capacity of local stem cell populations and on the mechanical stability of the fracture region. During enchondral bone formation fracture callus provides sufficient primary stability. The process of fracture healing is delayed in osteoporosis as can be deduced from animal models and clinical experience. Aetiological factors in terms of cell and molecular biology and also the clinical factors are not exactly characterized. Diminished bone strength and delayed callus formation negatively influences primary stability and biomechanical conditions. According to the literature the rate of implant and screw failure is between 1.0 to > 50% depending on the type of fracture and on the clinical situation, however the database is not solid. The delay of the healing process entails prolonged patient immobilisation, which in consequence leads to even more loss of bone and muscle and triggers perioperative complications. The necessity for research in this area is high. We have to identify molecular deficits of fracture healing in osteoporosis, to enhance operative procedures and to develop new multimodal therapeutic strategies. To be successful, research activities of basic scientists, engineers and biomedical scientists have to be combined, exploiting modern methods of cell and molecular biology, mouse genetics, and large animal cloning.