K wires (Kirschner wires) are a type of stabilization wire/pin used in orthopedic surgery. They are pointed stainless steel wires that can be used in multiple roles during internal fixation:
- as a temporary measure before more definitive fixation
- thin wires are especially useful for smaller bones (e.g. hands, pediatrics)
- in combination with plates and screws for complex fractures
- for fixation in patients with poor bone quality (lag screws may not have much purchase)
Steinmann pins (or intramedullary pins), a slightly earlier invention, are a similar type of fixation wire/pin. In early orthopedics the terms for the wires were sometimes used synonymously. Today, a Steinmann pin usually refers to a wire thicker than the K-wire.
- "wire": 0.9-1.5 mm
- "pin": 1.5-6.5 mm
K-wires used to be only inserted with open pre-drilling (in the 1920s), but the infection rate prompted development of a percutaneous approach (now with a pistol-grip wire driver). Pin-tract infections (PTI) are much less common than they used to be.
Another disadvantage of K-wire placement is the potential for migration, which can be especially problematic if the wire/pin migrates into the thorax or the abdomen/pelvis from an adjacent fracture fixation (e.g. from a sacral fracture into the pelvis). Bending the wire or use of threaded wires are thought to decrease the likelihood of migration.
History and etymology
The original Steinmann nail was introduced by the Swiss surgeon, Dr Fritz Steinmann (1872-1932) in 1907. Although four years earlier, in 1903 an Italian surgeon, Dr Alessandro Codivilla (1861-1912) described a similar method for repairing foot deformities with a bone nail and skeletal traction. Thus its alternative name, the Steinmann-Codivilla pin . The original Kirschner wire was introduced in 1909 by the German surgeon, Dr Martin Kirschner (1879-1942) . Both wires/pins were at first used for traction and only began to be used for fixation in the 1930s.