Fractures of the long thigh bone (femur) in children can be difficult to repair and stabilize. Although there are many methods for fixation (holding the broken pieces together until the bone heals), there are also lots of advantages and disadvantages to each one.
In this study, a pediatric orthopedic specialist designed a new nail to help improve outcomes in children with femoral shaft fractures. The device, a flexible interlocking intramedullary nail (FIIN) is made of a titanium alloy and has a slight give to it.
This give (also referred to as plastic deformation) makes it possible to thread the nail into the femoral canal (down the middle of the bone) starting from the top of the femur. There’s a slight bend or curve the surgeon must pass the nail through to get to the main part of the bone shaft. Having that slight plastic give makes it possible to accomplish this. The nail is also designed to allow either a right-handed or a left-handed surgeon to use it.
The hope was that the FIIN would reduce complications, improve healing time, and restore function faster than the other fixation procedures (OFPs). One of the most common and difficult problems with treating femoral shaft fractures using OFPs is limb-length discrepancy. Malunion of the fracture, pain, infection, and refracture are other concerns with OFPs. The authors hope to reduce the incidence of these with the new FIIN.
All children included in the study were between the ages of seven and 18 with femoral shaft fractures. There were two groups matched by age, weight, and fracture patterns: those who received the FIIN and a second group who received an OFP. X-rays were used to judge the location of the fracture as well as the diameter of the canal inside the femoral shaft where the nail would be placed.
There wasn’t a standard OFP used in the children in the OFP group. Surgeons chose the method of fixation that was best for each patient. Some used titanium elastic nails, while others placed an external fixator (outside the skin with nails through the skin and bone). In some cases, a metal plate and screws were used to hold the bones together.
For those patients who received a FIIN, there were two different sizes for the surgeon to choose from. Smaller diameter FIINs (5.5 mm) were used in children who weighed up to 100 pounds. A larger diameter nail was developed and used with children who weighed more than 100 pounds. The surgical procedure was described in detail for surgeons considering using these nails.
The FIIN is inserted in a slightly different place along the side of the hip from the standard entry point for OFPs. Location of the necessary incisions are provided in the article. Techniques to make it easier to pass the nail through the skin and steer it into the bone are also described.
The surgeon uses fluoroscopy (X-rays that show what’s going on inside the body) to complete this task. This type of imaging makes it possible to avoid overbending the nail tip, rotate the nail at just the right time, and get it in the best position to line up the broken ends of the bone. Once everything is in place, the pin is locked in place. Fluoroscopy confirms it’s time to close the incision and bring the patient out of the anesthesia.
Length of hospital stay was about the same for both groups. Amount of blood lost was greater in the OFP group but this may have been because of multiple trauma and more complex injuries. Patients were allowed to put weight on the operated leg when X-rays showed signs of bone healing. Usually, this was around three weeks after the surgery with the FIIN.
Full weight bearing was possible in the FIIN group 10 to 12 weeks after surgery. This was a full month sooner than for patients in the OFP group. The difference in time to weight-bearing was even more obvious in patients with multiple trauma. They were up and going twice as fast as the OFP group.
Only minor complications were reported with the FIIN. There were no cases of pain or skin problems. This was compared with both minor and major complications with the OFPs. Of course, comminuted fractures (many tiny pieces of bone) were more difficult to treat without complications in either group. Overall, the incidence (number of complications) for FIIN versus OFP was about the same and not considered statistically significant.
Complications within the OFP group included infection, osteomyelitis (bone formation in the soft tissues around the bone), refracture, or loss of blood supply to the bone. Children who weighed less than 100 pounds in the OFP group were eight times more likely to suffer one (or more) of these complications.
The authors conclude that less blood loss, shorter recovery time, and faster return to function, along with fewer complications makes their new device (the FIIN) a good choice when surgically treating femoral shaft fractures in children. And the FIIN can be removed nine months to a year later.
The increased rate of osteomyelitis with FIIN may be caused by the way the new nail is inserted into the bone. More study is needed to understand this problem. The fact that smaller children are especially likely to have better results with the FIIN over the OFPs will be also investigated further.