What is a K-wire used for?


What do you do with an osteosynthesis?

The human bone consists of a firm cortex (compacta) and a somewhat softer core, the cancellous bone. In the case of large bones, the interior of the marrow cavity is found in which the bone marrow lies; in old age it is increasingly replaced by fat. The bone is enveloped by the periosteum, the so-called periosteum.

Before the operation

Before the bone fracture is treated with an osteosynthesis, the bone pieces must be brought back into their correct position in relation to one another. This process is called reduction. In many cases, the reduction can be closed, i.e. without surgery. In this case, the doctor brings the fragments back to their original position by skillfully moving and pulling the broken bone. In complicated cases, the reduction is carried out during the operation.

Before applying an osteosynthesis, the surgeon disinfects the patient's skin and covers him with sterile cloths, leaving out the surgical area.

Screw fixation

In screw osteosynthesis, a distinction is made between lag screws and cancellous screws. In the Lag screw fixation The doctor drills the cortex of a piece of bone so far that a screw can slide into this hole. In the opposite fragment, the doctor drills a slightly smaller hole into which he cuts a thread for the screw with a special instrument.

If he now turns a screw into the holes, the piece of bone with the thread is pulled against the piece of bone with the sliding hole. By tightening the screw, the fragments are pressed tightly together.

The Cancellous screw has a long shaft with a short thread at the lower end. Here, too, the surgeon drills a hole in the bone in which the screw shaft can slide. Now he turns the cancellous screw into the drill hole so that the thread of the screw lies behind the break line. According to the same principle as with the lag screw, this creates a pull on the fragments, which then brings them together.

Plate fixation

With plate fixation, the surgeon first exposes the broken bone. Then he chooses a plate that fits the bone surface in its shape and size. He places this over the fracture line and fixes it with screws in the bone for all fragments. The fragments are firmly connected to one another by the plate.

Intramedullary nail osteosynthesis

The surgeon opens the medullary cavity of the bone with a wire or awl. He places a guide wire in this canal, over which a reamer is pushed into the medullary canal. The doctor uses this to expand the medullary cavity of the bone. Now he drives a long nail into the canal in the medullary canal, which clearly bridges the fracture gap. The long nail is now in the broken bone as an inner splint. All of this is done under regular x-rays to ensure that the nail and fragments are in the correct position. If necessary, the surgeon locks the nail with a cross bolt in the bone (locking nail) so that it cannot move within the medullary cavity.

Kirschner wire fixation

During osteosynthesis with the so-called Kirschner wire, the surgeon bridges the break point with one or more elastic steel wires. The wires are sunk deep into the cancellous bone through the bony cortex, but the upper end remains outside the bone. In this way, the surgeon can pull the wire out again after the fracture has healed

The Kirschner wire fixation is suitable for the treatment of fractures of smaller bones (e.g. fingers) and fractures in the area of ​​the growth plates (in young people). It is also used in the area of ​​the collarbone - usually with several wires in different puncture directions.

Since this form of osteosynthesis does not sufficiently stabilize the fracture for greater mechanical loads, a splint or a plaster cast must also be put on.

Tension band osteosynthesis

The tension belt osteosynthesis uses the tensile forces that pull the individual fragments apart and converts them into compressive forces that press the fragments together. To do this, the surgeon first inserts two wires (spike wires) into the bone so that they run parallel to each other and perpendicularly through the fracture gap. Here, too, the correct position of the wires is checked with an X-ray image.

A soft wire loop (cerclage) is now crossed on the outside around the protruding ends of the wires. A canal is now drilled into the bone on the other side of the fracture line. The wire loop is looped through this and is now taut. The doctor then bends the protruding ends of the spike wires so that they hold the soft wire loop securely.

External fixator

This form of osteosynthesis stabilizes (fixes) the bone fracture with an outer (external) frame. First, the surgeon makes small incisions in the patient's skin along the broken bone. Through this he drills holes in the bones into which he sticks long, solid metal rods, so-called pins. These are - mostly on both sides of the break - connected on the outside with a metal strut and thus stabilized.

Dynamic hip screw

This osteosynthesis is used for fractures of the femoral neck. To do this, the surgeon brings a guide wire into the part of the femoral neck near the hip joint under X-ray control. Using this, he now turns a screw with a short, thick thread into the femoral head.

He now screws a metal plate with a tubular receptacle into which the threadless part of the screw shaft can slide onto the upper outside of the thigh bone. The weight of the patient deflects the load in such a way that the fracture gap is compressed.

After the operation

After inserting the osteosynthesis, the doctor sutures muscles, connective tissue layers and skin one after the other and puts on a wound dressing. The patient can recover from the anesthesia and surgery in the recovery room.