The clavicle, or collar bone, is the most commonly broken bone among children up to the age of 18 years and representing between 10 percent to 15 percent of bone injuries in children under the age of 10 years. The clavicle can be broken by a direct hit to the bone, but it is a fracture that is most often the result of an indirect injury – when someone falls on their shoulder or on an outstretched hand, intended to break a fall. Some children are born with broken clavicles too.
Although it is important for all broken bones to heal properly, the clavicle needs to be strong enough and functioning well enough to support the arm and to help it be as mobile as possible. Usual treatment for a broken clavicle is applying a sling that keeps the affected arm still, allowing the clavicle to set. Surgery is not a common option, as doctors feel that slings are the way to go. But, although it is strongly believed that this type of treatment is enough and that slings just about always result in a healed, joined bone, there hasn’t been a lot of research on it. Seeing as bones grow and change throughout childhood, it is possible that this could affect clavicle healing. As a result, the authors of this study wanted to look at the postnatal (since birth) growth pattern of the collar bone.
To do the study, researchers examined chest x-rays of 961 patients who were 18 years old or younger and who had been diagnosed with a fractured clavicle. The researchers divided the patients into 19 groups: newborn to 11 months and then one group for each year of age. Each of these groups was divided again by male/female lines.
Evaluating the clavicle involved measuring the length in millimeters by three researchers to ensure consistency in the measurements. Throughout the study, some people were measured in different groups, as they grew older: although 850 were measured only once, 94 were measured twice, 12 three times, three four times, and two five times.
The findings showed that among 18 years olds, the average length of the clavicle was 149 mm, give or take 12 mm for girls, but in boys it was 161 mm, give or take 11 mm. The researchers noticed that both boys and girls had a steady growth rate after the age of 12 years, but slower for the girls (2.9 mm per year) than the boys (5.4 mm per year).
Looking at the younger ages, the researchers determined that among girls, the majority of the clavicle growth (80 percent) was done by the time they were nine years old. In boys, the majority (80 percent) was by the age of 12 years. This finding shows that the healing of a fractured clavicle may not be as easy in older children as it is in younger children – there is not as much bone formation going on in the older children years. In this case, other treatments may be a more viable option.