Postoperative Malalignment Following Reamed Intramedullary Nailing for Distal Tibia Fractures in Adults: A Prospective Observational Study

The lower leg is a complex structure where the shinbone, or tibia, meets the ankle. When a fracture occurs near the bottom of this bone, just above the ankle joint, the injury is particularly tricky to treat. The bone in this area is thin and sits just beneath the skin, leaving little room for error. If the bone heals in a crooked position, even by a small amount, it can alter how a person walks and may lead to painful arthritis in the ankle years later. Surgeons often use a long metal rod, called an intramedullary nail, that is inserted down the center of the bone to hold the broken pieces together while they heal. However, keeping the bone perfectly straight while driving this rod into place is difficult, especially near the ankle where the bone flares out. Doctors have long known that the bone can end up angled incorrectly, but they have been searching for better ways to predict and prevent this during the surgery itself.

A team of surgeons at a major hospital in Nepal set out to understand exactly how often this misalignment happens and what factors might cause it. They focused on a specific technique where the metal rod is inserted into a hole drilled through the center of the bone. To guide the rod, they used a concept called the "distal nail target." Imagine the metal rod as a straight line extending all the way to the bottom of the bone; the point where this line would hit the ankle joint surface is the target. The researchers wanted to see if hitting the center of this target area during surgery guaranteed a straight bone, or if other factors, like the shape of the break or whether the smaller bone next to the shin was also fixed, played a bigger role.

The study followed thirty adults who had suffered fractures in the lower part of their shinbone. These patients were treated between August 2024 and May 2025. During their operations, the surgeons used a special X-ray camera to watch the metal rod as it was being placed. They carefully noted exactly where the rod ended up relative to the center of the ankle joint, both from the front and from the side. After the surgery, they measured the angles of the healed bone to see if it was straight. They defined a successful outcome as the bone healing within five degrees of its normal, natural angle. Anything outside that range was considered a misalignment.

The results showed that misalignment was a common occurrence, happening in seven of the thirty patients, which is roughly one out of every four cases. This confirms that even with modern techniques, keeping the bone perfectly straight in this difficult area remains a significant challenge. When the researchers looked closely at the seven cases where the bone was crooked, they found that the position of the metal rod did not tell the whole story. In more than half of these misaligned cases, the rod had actually been placed right in the center of the target area. This suggests that simply aiming for the center is not a foolproof guarantee of a perfect result.

The shape of the broken bone seemed to matter more than the precise spot where the rod was placed. The misalignments were most common in patients whose fractures were straight across or slanted, rather than spiraling around the bone. These simpler break patterns appeared to be less stable and more likely to shift during the healing process. Another key finding involved the smaller bone that runs alongside the shinbone, known as the fibula. In six of the patients, the surgeons also fixed this smaller bone with a plate or a nail. Only one of these six patients developed a misalignment in the main shinbone. In contrast, among the patients who did not have their fibula fixed, the rate of misalignment was higher. This suggests that stabilizing the smaller bone might act as a helpful support, keeping the main bone in the correct position while it heals.

The study also examined whether the angle of the metal rod in the front-to-back direction made a difference. While the numbers were too small to be absolutely certain, the data hinted that rods placed toward the back of the bone were more likely to be associated with misalignment than those placed in the center. However, the researchers could not prove a direct cause-and-effect link between the rod's position and the final angle of the bone. The study did find that the average angles of the healed bones were very close to normal, indicating that for most patients, the surgery was successful despite the challenges.

Ultimately, this research highlights that treating fractures near the ankle is a delicate balancing act. While placing the metal rod in the center is a good starting point, it does not ensure a perfect outcome on its own. The type of fracture and whether the supporting fibula is fixed appear to be just as important. The surgeons concluded that paying close attention to these factors could help reduce the number of crooked healings. They noted that their study was relatively small and that more research with larger groups of patients is needed to confirm these findings and to develop even better strategies for ensuring that patients walk away with straight, functional legs.