A new titanium nail for the femur: Concept and design

Abstract

Intramedullary nailing of the femur is an established and widely used technique in traumatologic and orthopedic surgery, with a broad spectrum of indications. It has become the preferred treatment for diaphyseal fractures due to good alignment at the fracture site, preservation of the periosteal blood supply and soft tissue, and the early restoration of function. Kuentscher's basic principles of mechanical and biological fracture healing with closed reduction, preservation of the fracture hematoma, and fixation with an intramedullary nail according to the fracture pattern, is still valid today [37]. Fixation of the original intramedullary Kuent-scher nail is based on the cylindrical reaming principle and transversal spring locking of the cloverleaf nail profile. The original idea, to obtain stability with a larger intramedullary blocked nail, was abandoned with the development of locking nails. With this remarkable development, the spectrum of indications expanded widely. However, to achieve axial and rotational stability, the new generation of intramedullary nails has to be interlocked proximally and distally [2, 9, 16, 34]. Using these technical principles, it has been demonstrated by numerous authors that intramedullary fixation of diaphyseal long bone fractures is more effective and mechanically superior to plate fixation [2, 20, 34, 52]. Conventionally, locked intramedullary nailing requires pre-reaming of the medullary canal for insertion of a larger diameter nail. Nevertheless, there are experimental and clinical data indicating that reaming may have adverse consequences of systemic embolization [55], pulmonary damage [45], hemostatic activation [27], reduction of bone strength [46] and destruction of the endosteal blood supply [50, 51]. Accordingly, the trend in nailing shaft fractures led to unreamed and limited-reamed techniques and the use of small-diameter nails. However, a high incidence of complications including implant failure, delayed unions, nonunions and malunions has been reported with the use of small-diameter nails and unreamed techniques [1, 5, 17, 26, 30, 53]. Many of the complications mentioned above are due to the poor primary stability of the osteosyntheses. Another disadvantage of unreamed nailing is the occasional appearance of distraction at the fracture site, due to endosteal resistance during the insertion process. The resulting fracture diastasis is a well-known cause of prolonged bone healing and nonunion. Clear improvement concerning the aforementioned issues has been achieved with the development of new implant materials and different locking options, as well as the development of an integrated compression mechanism. With the same nail diameter, for the appropriate fracture, better primary stability can be achieved with the compression nail compared to other intramedullary locking nails [6, 7, 21, 39]. In addition, through the compression mechanism, which allows dispensed fragment apposition, a primary fracture diastasis can be avoided [43]. © Springer Berlin Heidelberg 2006.