It can be difficult to advise parents or caretakers of children with traumatic fractures of the talus because this type of fracture is rare. We know how these fractures develop (the mechanism of injury). But other information on talus fractures in children is limited. Who gets these (risk factors), what's going to happen (natural history), and what can go wrong (complications)?
The talus is located just above the calcaneus (heel bone). The talus has a bit of an odd shape with a main square-shaped body and a small extension of bone coming off the body called the talar neck. It is sandwiched between the calcaneus and the bones you feel on the top of your foot where the end of the tibia (lower leg) meets the foot. The talus is an important bone in ankle motion because it helps create the rocking motion needed for front-to-back and side-to-side movement of the ankle/foot complex. It is the link between the other major joints in the ankle.
In this study from Children's Hospital in Boston, the records of all children who had a talus fracture over a 10-year period were reviewed. Data was gathered on age of the child at the time of injury, how the injury happened, and the exact type of fracture.
Any injuries to the surrounding soft tissues or other bones were also recorded. X-rays and treatment administered were reviewed. The final piece of important information (and really what the surgeons wanted to know) was the number and type of complications that occurred after treatment.
It turns out that many of the injuries occurred during high-impact sports. The ankle/foot was in a position of dorsiflexion (foot flat on the ground, tibia forward over the foot). Other talar fractures were caused by a fall landing on the heels/foot or as a result of a car accident. A force down through the leg too great for the strength of the bone resulted in a fracture.
Children of all ages (from one up to 18) experienced talar fractures. The most common place for a talar fracture was the talar neck. There were fractures of the talus body as well. But there were some children who had more than one area of the talus broken (neck and body). High-energy injuries were more likely to result in damage to other areas of the foot and ankle.
Treatment was with open reduction and internal fixation (ORIF) for about a third of the group. In this procedure, the surgeon makes an open incision and uses hardware such as screws or pins to hold the broken bones together until healing takes place. The majority of the children were treated with immobilization in a cast without additional surgery. Most kids were back up on their feet and engaged in all activities on an average of nine weeks. Displaced fractures (bones separated) took longer to heal than nondisplaced breaks.
What kinds of problems developed after treatment? This is the real focus of the study. Post-traumatic arthritis was the most common complication affecting 17 per cent of the group. Second to arthritis were nerve injuries and avascular necrosis (loss of blood to the bone causing death of bone tissue). Most of the nerve injuries were temporary and healed. Only one patient had residual loss of sensation.
The authors were particularly interested in the low rate of avascular necrosis because this is much more common among adults. They thought perhaps the children had fewer displaced fractures the number of cases of necrosis was lower. Perhaps the thicker periosteum (outer layer of bone) offers some protection. And, of course, supportive cartilage in and around the joint in children is more flexible allowing for more give and bend during trauma.
There were no cases of infection or problems with wound healing and only one fracture that failed to heal. A couple of children/teens needed another surgery to help stabilize the joint. A closer look at those who developed joint problems later showed that these patients had high-energy injuries and a displaced fracture. Likewise the one nonunion and all cases requiring additional surgery were displaced fractures.
In summary, talar fractures in patients under the age of 18 are more common in teens who are involved in sports or driving cars. Younger children are less likely to fracture this bone. When younger children experience a talus fracture, it is often less severe and less involved than in older children and teens. The data from this study does not point to avascular necrosis as a likely complication following treatment in this age group.
Although this is the largest study published on the topic of talus fractures, there were only 29 cases over a 10-year period of time. There is some suspicion that more of these fractures will be seen in the future as more and more children participate in high-impact sports. Having some knowledge of what to expect will help surgeons plan for, evaluate, and treat these injuries when they do occur.
Reference: Jeremy T. Smith, MD, et al. Complications of Talus Fractures in Children. In Journal of Pediatric Orthopaedics. December 2010. Vol. 30. No. 8. Pp. 779-784.