[Technique and biomechanics of Kirschner wire osteosynthesis in children]

Safe and stable fixation of metaphyseal and epiphyseal fractures by Kirschner (K-)wire osteosynthesis. Use of various K‑wire configurations depending on the fracture morphology.

In accordance with the AO Pediatric Comprehensive Classification of Long-Bone Fractures (PCCF), all Salter-Harris (SH) and metaphyseal fractures as well as fractures of the foot and hand independent of the reduction technique, closed or open, provided that adaptation osteosynthesis allows sufficient stability. Fixation/immobilization in a plaster cast is mandatory after K‑wire osteosynthesis.

All diaphyseal fractures, if a K-wire is not used as an intramedullary nail. Fractures that can not be correctly reduced or are nonreducible fractures.

After closed or open, as anatomical reduction as possible, one, two, occasionally three K‑wires per fragment are inserted under fluoroscopic control. Care must be taken that the K‑wires optimally capture the fragment to be fixed as well as the main fragment (metaphysis). It must therefore be possible to make a strictly lateral and correct anteroposterior x‑ray by image intensifier. It is important that the C‑arm can be positioned at the appropriate level. Rotating the limb should be minimized, as prior to fixation the previously reduced fragments may shift again, resulting in poor K‑wire fixation. Depending on the morphology of the fracture, size of the fragments and location of the fracture (humerus, forearm, femur or tibia, hand or foot), the K‑wiring technique must be adapted, e.g., mono-laterally crossed, mono-laterally divergent, in an ascending or descending direction, or the most commonly used ascending crossed technique. In most cases, the K‑wires protrude through the sin and the exposed ends are bent. This allows removal without renewed anesthesia in the outpatient setting. K‑wire osteosynthesis is neither a compression osteosynthesis (OS) nor a neutralization OS, but is always an adaptation and fixation of the fragments. Therefore, K‑wire OS always needs additional immobilization using a plaster or prefabricated splint.

Immobilization in plaster cast for 4-5 weeks, depending on the age; care must be taken to avoid interference between the cast and the skin/K-wires.

With technically and optimally performed fixation and correct indication for K‑wire OS, as well as adequate posttreatment, very good to good results are achieved.