Girls and boys tend to fracture their forearms for different reasons

Girls and boys tend to fracture their forearms for different reasons

What are forearm fractures?

Forearm is the part of the arm between the wrist and the elbow and consists of two bones: the radius and the ulna. Distal forearm fractures occur near wrist in one or both of these bones and are the most common of all paediatric fractures accounting up to 30% of all fractures. The incidence of these fractures has risen by one third over the past three decades boys showing predominance over girls.

Why do kids get forearm fractures?

Kids typically fracture their forearms after falling from standing height or less. Forearm fractures peak in early to mid-puberty around the ages of 12-14 years. So why do kids fracture so frequently during this age span? It has been suggested that bone strength can’t keep up with rapid growth spurt at puberty. Because of this, the bone structure alters leading to temporary increase in the risk of fracture.

During our study we noted key differences between how boys and girls fractured their forearms.

The difference between forearm fractures in girls and boys

Our findings suggest that forearm fractures during growth are indeed sex-specific. For girls, we found that fractures were associated with weaker bone strength, influenced by deficits in both cortical and trabecular bone.

In boys, we found that bone outcomes didn’t differ between cases and controls. It may be that modifiable factors such as body composition, balance, and physical activity play an important role in determining fracture risk in boys.

Girls more commonly experienced fractures during playground activities, while boys tended to experience fracture while playing in team sports. Other common reasons for fractures in both boys and girls were accidents while bicycling, skiing and snowboarding, skateboarding, riding a scooter, and rollerblading.

Will they get more fractures? What can you do to prevent more fractures in the future?

There is compelling evidence that children and youth who fracture at a young age are more likely to have a subsequent fracture later in life. Therefore, after a bone fracture, it is important to review the lifestyle related risk factors that can easily be modified. For example, is the child getting enough physical activity to guarantee the optimal bone growth? Are they getting sufficient vitamin D and calcium intake? Childhood and youth is when the majority of bone mass is accrued. Building stronger bones during childhood gives a solid foundation for a fracture-free adulthood.

This study helps us to characterize those factors at the different stages of growth and therefore to implement effective interventions to prevent fractures—at every age.

How we did our research at CHHM?

CHHM houses one of only a few available high-resolution peripheral quantitative computed tomography scanners (HR-pQCT, Scanco Medical). HR-pQCT is a state-of-the-art tool that can be used to measure bone microstructure in the growing skeleton non-invasively and is able to characterize the hierarchical structure of both bone compartments—trabecular and cortical—at high resolution and with excellent precision. Furthermore, bone strength—the “bottom line” in fracture prevention—can be estimated with finite element method that uses HR-pQCT scans.

This study measured and interviewed 173 children and youth between 8 and 15 years who had recently sustained a distal radius fracture and 146 similar age fracture-free children and youth to study the risk factors causing forearm fractures.

Cross-section of a non-fractured forearm (on left) and fractured forearm (radius fracture, on right) scanned using HR-pQCT (XtremeCT, Scanco Medical). 

Note thicker and more dense cortical bone shielding the spongy interior of the bone (Trabecular bone) on the left scan compared to the scan on the right. This indicates that the cortex is thinner and less dense.