Intramedullary Nailing of Metaphyseal Fractures of the Lower Extremity

Intramedullary nailing is a worldwide accepted technique for stabilization of fractures of long bones. Technique, instruments and implants primarily have been developed for the fixation of short (transverse and oblique) diaphyseal fractures. First generation nails were hollow and slotted, which gave them some elasticity. When the tip of the nail passed the fracture gap, picked up the opposite fracture fragment and was driven further down, the longitudinal axis of the bone was restored and the extremity realigned. Bone length was restored by closure of the fracture gap. The tight connection between the deformable hollow nail and the inner cortex at the isthmus realized a press-fit, which achieved a very stable bone-implant construct. The nail had the function of a weight-shearing implant. Interlocked nails represent the second-generation nails. They changed the spectrum of indications for nailing considerably. Not only short middle-third shaft fractures, but shaft fractures of all types (from transverse to comminuted) and all localizations can be stabilized with an interlocked nail. Due to interlocking, length and rotation are controlled. The nail bridges the area of instability, being a weight-bearing implant. Small diameter, solid nails formed the next generation of nail implants. They were conceived for the provisional treatment of fractures with an enhanced risk of postoperative infection such as open fractures or closed fractures with severe soft tissue damage. They were increasingly used for minimal invasive treatment of closed fractures without soft tissue damage as well, as reaming was not necessary and endosteal blood supply less damaged. Nevertheless, it became clear that they were connected with a higher incidence of implant failure and revision surgery. Another development was the creation of nails with multiple and angular stable interlocking options. Major advantage is that high stability is obtained in the fracture fragment, in which multiple interlocking is used. This property gives the possibility of nailing fractures close to a joint with a short fracture segment (24). Nevertheless, intramedullary nailing of metaphyseal fractures remains controversial. Major complications to be avoided are malalignment, delayed union, nonunion and implant failure due to suboptimal fracture reduction (23).