Fractures, or breaks, of the tibia (shin bone) are the most common type of break in the longer bones of the human body. These fractures can be clean breaks with little or no bone movement or they can be severe breaks that also cause damage to the muscles, blood vessels, nerves, and body tissues around the broken bone.
When the tibia is broken in the bottom third of the bone (closest to the foot), after healing, there is a higher chance of the bones not lining up properly. In fact, this happens in about 84 percent of cases. The most common of these is when the farthest part of the bone moves away from the midline of the body. Unfortunately, this can be difficult to treat.
To fix this type of fracture, one type of repair the surgeons use is a special type of nail to join the broken bone parts. Part of the bone can be quite wide, however, making it difficult for the nail to be stabilized in the bone. This leads to the bones not lining up properly again. As well, because the lower leg moves every time the knee is bent (flexed) and straightened because of the tendons pulling on the bone, this also makes it harder for the bones to stay in the aligned, or straight, position.
When surgeons choose the type of nail to be used, they must take into account the shape of the nail, where and how the nail is curved, and so on. Proper choice will reduce the chances of the bone not being properly aligned.
The surgery itself will also play a role in unsuccessful bone alignment. The starting point of where to place the nail is critical and surgeons should start it as far as possible away from the break and work towards the break. If necessary, the surgeon can use fluoroscopy (x-ray with dye) to use as a guide for surgery placement.
Other techniques to improve how the bones align during healing include how the knee is positioned during surgery. In some cases, surgeons flex the knee, which reduces the amount of tension on the tendons surrounding the fractured part of the bone. However, the knee should not be bent more than 10 to 15 degrees, they suggest. There is one disadvantage to this approach though. In order to proceed, the surgeons must do an arthrotomy, make an incision in the knee joint itself.
Other surgeons use a plate to line up the bones. The pates are locked into place with screws. The surgeons do point out that using screws adds to the cost, but it also provides a stronger fix. The plate can be removed at a later date if desired.
A third choice is the use of blocking screws. These screws are used with nails but the screws block the nails from going outside of where the surgeon wants them to be. According to research done by Krettech et al, this approach increases the strength of the healed fracture by as much as 25 percent.
Finally, another option is external fixation. With external fixation, a support of clips, pins, and clamps hold together the fractured bone from outside the body, with parts of the hardware going through the skin to stabilize the bone. This procedure should be saved for situations where there is too much damage in the tissue around the fractures that would make interior fixation too difficult.
One of the risks of surgery is the risk of developing an infection. This can be difficult and tibial fractures seem to be particularly difficult to treat. In order to decrease the rate of infections, surgeons must be meticulous about debriding or removing dead or tissue that will die from around the fracture.
Infections can occur at any time after the fracture, from the acute period (up to four weeks after the fracture) to several months or even years later. Physicians have noted that certain types of injuries have more infections than others. This includes crushing types of fractures and open fractures (where the skin has been broken). As well, if there has been an open fracture, if it was exposed to dirt or contamination of any sort, the risk of infection rises dramatically. Other issues that can affect if a person develops an infection include their nutritional status, certain illnesses and health issues (such as diabetes), smoking, and drug addiction.
Once an infection has been diagnosed, treatment includes debridement to be repeated until all dead or non-viable tissue is removed. This is followed with antibiotics. If the wound cannot be closed (skin stitched up), surgeons can choose to use a vacuum-assisted closure device, which helps protect the wound while encouraging healing.
If the bone doesn’t join at all, this is called a non-union of the bone, or an aseptic non-union of the bone. This happens in about 3 percent of all tibial shaft fractures. Non-unions can be the result of a person’s health status, just like the risk of infection. As well, some medications, such as NSAIDs (nonsteroidal anti-inflammatory drugs) and bisphosphonates, medications given most often for osteoporosis, can interfere with healing.