Which tibial fractures are suitable for interlocking intramedullary nail fixation technology? What are the advantages?

Author: Wang Qiwei, attending physician at Peking University First Hospital

Reviewer: Li Jun, deputy chief physician, Peking University First Hospital

Tibial fractures are more common in the middle part of the lower leg, but some also occur near the knee and ankle joints.

Figure 1 Original copyright image, no permission to reprint

Treatments for tibial fractures include manual reduction, plaster fixation, and surgical treatment. Severe fracture displacement; involving the articular surface; partial open fracture; fracture causing damage to blood vessels and nerves may require surgical treatment, and minimally invasive surgery is the first choice.

Currently, there are three types of minimally invasive treatments for tibial fractures, namely, small incision locked intramedullary nail fixation technology, small incision or limited incision plate reduction technology, and percutaneous pinning external fixator fixation technology. The most commonly used one is the locked intramedullary nail fixation technology.

Today we are going to talk about the locking intramedullary nail fixation technique for tibial fractures.

The tibia is a long tubular bone. Anatomically, the center of the bone is called the medullary cavity. After a tibia fracture, a long metal rod is used to connect the broken bones. Usually, the intramedullary nail is placed in the center of the long tubular bone, that is, into the medullary cavity. The premise is to reset the fracture and restore the continuity and integrity of the bone. The diameter of this metal rod is 7-12 mm, so it can be called a needle, so this fixation method is called intramedullary nail fixation technology.

Why is it called a locked intramedullary nail? Because the metal rod is inserted into the long tubular bone to connect the broken bones, but it cannot effectively prevent the fracture from rotating. There are holes at the head and tail ends of the metal rod, and nails are inserted at both ends and locked with two nails, which can effectively maintain the length and prevent rotation, so this internal fixation device is called a locked intramedullary nail.

Figure 2 Original copyright image, no permission to reprint

Traditional interlocking intramedullary nail fixation technology treats mid-calf fractures, that is, tibial shaft fractures, and originally only one or two interlocking nails were placed. Now, with the development of intramedullary nail manufacturing technology and surgical instruments, multiple interlocking nails can be fixed at both ends, thus expanding the scope of interlocking intramedullary nails for tibial fracture treatment.

In addition to tibial shaft fractures, tibial fractures close to the ankle and knee joints, where the articular surface damage is not very serious, can also be treated with locking intramedullary nailing. Of course, special attention should be paid to stability, especially the implantation direction and number of locking nails, otherwise the use of intramedullary nailing to fix the epiphysis is likely to cause poor reduction and unreliable fixation.

In general, currently mid-tibial shaft fractures and epiphyseal fractures close to the joint and with little displacement can be treated with intramedullary nail fixation.

The biggest advantage of using locking intramedullary nails to fix tibial fractures is that they are minimally invasive. If traditional techniques are used to fix with steel plates, the soft tissue needs to be cut open to expose the fracture ends, and the fractures need to be assembled and repositioned like building blocks under direct vision, and then fixed with steel plates. Although it can correct fracture displacement and is relatively convenient to operate, it increases the impact on blood circulation around the fracture ends, and the blood vessels and nerves around the soft tissues are easily damaged, resulting in relatively large trauma.

Intramedullary nail fixation technology can make a very small incision far away from the fracture. The incision is generally only three or four centimeters long, and a long tubular metal can be inserted into the bone marrow cavity. The surgical incision can be made far away from the fracture to reduce interference with the blood flow at the fracture end. It can also be made far away from important blood vessels and nerves to avoid damage to blood vessels and nerves.

Therefore, the biggest advantage is that it is minimally invasive, which protects the blood supply to the fracture ends and is conducive to fracture healing.

The second advantage is stable fixation. To use a vivid metaphor, if you hold an object by hand and hold one side of it, it is easy to fall, but if you hold it in the middle of the object, it will be more stable and not easy to fall. The intramedullary nail is placed in the center of the long tubular bone to connect the two ends of the fracture. From the perspective of biomechanics, this type of fixation is called central stress sharing fixation, not an eccentric fixation. It can fix the bones very stably and at the same time transfer the force to the fixed bones to the greatest extent possible, so that the fracture is close to the load-bearing state under physiological conditions, which is conducive to promoting bone healing.

Other internal fixation methods, such as the most commonly used steel plate, are placed on one side of the tibial shaft, which is a lateral, eccentric fixation method. Compared with central stress-sharing fixation, this method has lower stability and has a certain impact on fracture healing and early weight-bearing.